remineralize reverse osmosis

Best Reverse Osmosis System 2022: Top Picks, Reviews & FAQ

Looking for the Best Reverse Osmosis System / Water Filter for Your Home?

You’ve come to the right place.

Reverse osmosis (RO) filter systems remove more impurities from home water systems than any other type of water filter.

Most RO filters can remove particles larger than 0.001 microns – which eliminates bacteria, viruses, and cysts as well as harmful chemicals, tiny dirt particles, and dissolved solids.

RO systems are so good at cleaning tap and well water that they are often used in industries with extremely high standards of water quality such as pharmaceuticals and bottled water.

A residential RO system is the best choice if your goal is to provide the cleanest and safest purified water for drinking, cooking, pets, and other uses.

What's in This Buying Guide

Table of Contents

In this in-depth buying guide, we compare and review the best reverse osmosis water filter systems, most of which can be bought online. 

We also discuss everything you need to know about RO systems, including how they work, how to select the best RO filter for your needs, as well as the basics of RO filter installation and maintenance

This guide will take you 10 minutes to read – or maybe 2 minutes, if you just want our take on top picks.

Best Reverse Osmosis Water Systems: Comparison Table

RO System
Best For
Water Production
Home Master TMAFC-ERP

Home Master TMAFC-ERP
Best overall
$$$12 x 16 x 20 inches
7-stage with non-electric permeate pump
75 GPD
Home Master TMHP HydroPerfection
Home Master TMHP HydroPerfection
Best protection
16 x 8 x 5 inches
9-stage with UV protection and a permeate pump
75 GPD
iSpring RCC7AK
iSpring RCC7AK

Link goes to Amazon

Best price
$$14.5 x 5.2 x 18.5 inches
6-stage with alkaline filter
75 GPD

Link goes to Amazon

Best capacity
$$16 x 5.2 x 17.5 inches
5-stage with long-lasting filters
90 GPD
iSpring RCC7
iSpring RCC7

Link goes to Amazon

Best value
$14.5 x 5.2 x 17.5 inches
5-stage with double carbon filters
75 GPD
Express Water RO5DX
Express Water RO5DX

Link goes to Amazon

Best budget
$16.2 x 18.8 x 18.1 inches
5-stage with leak-stop valve to prevent flooding
50 GPD
iSpring RCC7AK-UV
iSpring RCC7AK-UV

Link goes to Amazon

Best features
14.5 x 5.2 x 19.5 inches
7-stage with alkaline and UV filters
75 GPD

Link goes to Amazon

Best remineralization
16 x 5.2 x 17.5 inches
6-stage with calcium remineralization
75 GPD
Express Water ROALK10DCG
Express Water ROALK10DCG

Link goes to Amazon

Best alkaline water
15 x 14 x 5 inches
10-stage with a 5-stage alkaline filter
100 GPD

Link goes to Amazon

Best for temporary use
15.5 x 6.5 x 6.5 inches
4-stage portable countertop RO filter
90 GPD
Whirlpool WHER25
Whirlpool WHER25

Link goes to Amazon

Best space saver
13.5 x 14.5 x 15.5 inches
3-stage with compact design
18 GPD
Brondell RO Circle
Brondell RO Circle

Link goes to Amazon

Best water saver
13.8 x 9.2 x 16.5 inches
4-stage with a smart valve and modern design
50 GPD
iSpring RCS5T
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Link goes to Amazon

Best overall$$$$
14 x 11 x 18 inches
5-stage with electric booster pump
500 GPD

Best Reverse Osmosis Water Systems: Reviews

We believe the Home Master TMAFC-ERP Artesian RO System is the best choice for most homes.

It filters up to 98% of chemicals and contaminants out of the water, is extremely reliable (comes with a 5-year warranty) and it produces great tasting water thanks to a double remineralization process.

The price is reasonable, too – considering the full feature set, flow rate performance, and 2,000-gallon capacity.




1. Multi-stage Filtration Removes 98% of Contaminants

A multi-stage filtration system increases the efficiency of the system and increases the lifespan of the RO membrane at the core of the filter.

Sediment and carbon pre-filters filter out silt, sand, chemicals, and chlorine before the water gets to the RO membrane. These contaminants can overload the membrane and even damage it.

Most RO systems use standard activated carbon filters to remove chlorine and chemicals.

The Home Master RO system uses catalytic carbon instead.

Does it matter?

Yes, it does. Catalytic carbon has better filtration performance, especially against chloramine, a chlorine-alternative disinfectant, that is used in some cities.

Ordinary activated carbon is not very good at removing chloramine.

Once the pre-filters remove chemicals and suspended particles, the water passes through the RO membrane where the tiniest and toughest impurities are removed.

These include microorganisms, total dissolved solids including heavy metals, and any remaining chemicals.

Overall, the Home Master RO system removes up to 98% of impurities from your drinking water.

2. Double Remineralization for Great Tasting Water

Not all the stages in the Home Master RO system are for filtering. Two of the stages are specifically there to improve the taste of the water.

Purified RO water tends to be slightly acidic, which affects the taste of water. That’s because the RO membrane strips out dissolved minerals.

The Home Master adds back the healthy minerals at two points: only before the water goes into the storage tank and just before the water comes out of the faucet.

The result is neutral or slightly alkaline water that tastes great. Most customers compare it to the taste of premium bottled mineral water.

3. Integrated Permeate Pump Reduces Water Waste

This is one feature you won’t find in most RO systems.

The integrated permeate pump does two things:

  1. Increases the flow rate out of the faucet. 
  2. Reduces the amount of wastewater.

While most RO systems have wastewater to pure water ratio of 4:1, the Home Master TMAFC-ERP Artesian RO System only flushes 1 gallon of water for every gallon of purified water produced – a FAR more efficient 1:1 ratio.

4. Wider Fittings = Increased Flow Rate

Another design feature that helps maintain a high flow rate from the faucet is the use of wider 3/8” fittings instead of the standard 1/4″ fittings.

5. Low Maintenance

The Home Master TMAFC-ERP RO filters about 2,000 gallons of water before it requires filter changes. For most families, that’s a whole year’s worth of water.

Bottom-line: You only need to change the filter once a year.

Filter changes are easy, and you won’t need tools – not even a wrench.

This Home Master system uses a modular design where the filter and filter housing are one unit. So, you remove the entire filter and put in a new one – easy and quick without having to touch a messy cartridge.

This modular design has another significant advantage: Longevity.

With most RO systems, you can go for years without changing the filter housing. Most people replace the cartridges and don’t get new houses even when the manufacturer-recommended lifespan (usually five years) expires.

This causes leaks and can even create a flood when the housing eventually breaks completely.

Home Master’s design is easier and cheaper to maintain and guarantees a longer lifespan.


1. Installation Takes Time

You’ll encounter this issue with all under-counter water treatment systems. It’s not unique to the Home Master RO filter.

Installation typically takes 2-4 hours. If you don’t have an entire afternoon to set it up, consider having a pro do it for you.

2. It’s Big

The Home Master RO system will take up half or more of the space under your counter. Some customers had to do a bit of retrofitting to get the system to fit correctly under the sink.

3. Slight Noise

You may notice the sound of water draining or entering the tank if you are in the same room.

In time, this becomes more of background noise and is less noticeable.



For families looking for a high-performance under-sink RO system that’s not too expensive, we highly recommend the Home Master TMAFC-ERP filter.

Home Master has a knack for creating high quality and high-performance water treatment products.

Their TMAFC-ERP Artesian RO System above is the best overall for most families.

But if you need more protection from water contaminants to upgrade to the Home Master TMHP HydroPerfection Undersink RO water filter.

In addition to the carbon filters and RO membrane used in the TMAFC-ERP system, the TMHP HydroPerfection system also includes a UV filter that provides extra protection from germs.

A double remineralization process produces the same great tasting water as the TMAFC-ERP filter.




water osmosis systems
1. Five-Stage Filtration With UV Filter

The HydroPerfection system consists of two pre-filters.

A fine sediment filter captures suspended particles such as sand and silt. This eliminates water turbidity and prevents these impurities from overloading the RO membrane.

A catalytic carbon filter removes chlorine, chloramine, and various other chemicals, including pharmaceuticals and pesticides.

It matters that the carbon filter is catalytic, not the standard activated carbon filter.

A catalytic filter is the only one that can efficiently remove chloramine, which some cities use instead of chlorine to disinfect water.

At the core of the system is the RO membrane that removes heavy metals, dissolved total solids, and microorganisms.

The UV lamp complements the RO membrane, neutralizing any remnant bacteria and viruses to ensure your drinking water is entirely safe.

An activated carbon filter gives the water a final polish just before it comes out of the faucet to get rid of any remaining smells and tastes.

2. Double Remineralization Improves Water Taste

In addition to the five filters, the HydroPerfection system also features two points of remineralization.

Just before the water goes into the storage tank and just before it pours out of the faucet, small amounts of calcium and magnesium are added to the water.

This restores the ‘natural’ taste of the water and slightly raises its pH.

Unlike the water from other RO systems that has a certain acidic tang to its taste, the RO water from the HydroPerfection filter tastes just as good as bottled mineral water.

3. Integrated Permeate Pump and Larger Fittings Increase Flow Rate

The integrated permeate pump and wider fittings increase the flow rate out of the faucet, making it easier to fill large water bottles and pitchers.

The permeate pump also reduces the amount of water wasted by the system, resulting in a highly efficient 1:1 ratio.

4. Low-maintenance Modular Filter Design

You just have to replace the filters only once in a year. Thanks to the system’s high 2,000-gallon capacity –you don’t have to struggle with a wrench or touch a messy wet cartridge.

Home Master uses a modular design where the filter cartridge and filter housing are integrated into one unit.

This has two big advantages: it makes maintenance easier and increases the longevity of the entire system, since the filter housing never gets a chance to get all rusted and leaky.


1. Installation Takes Time

Similar to other under-counter RO water filters, it will take you a full afternoon to set up the system. Consider hiring a pro if you are too busy.

2. The Filter Takes Up a Lot of Space and Requires an Outlet

The system will occupy half or more of your under-sink space. It will be a tight fit if you don’t have much space under your sink.

The addition of a UV filter adds another complication – you need a nearby outlet to provide power to the UV lamp.

If you don’t have one under the sink, you’ll have to get one installed by an electrician.

3. A Bit Pricey

For the extra UV protection, you have to spend more on the HydroPerfection RO filter compared to the Home Master TMAFC-ERP and other RO systems without UV.

But we think it’s worth it for peace of mind that your water is germ-free.


If you are very concerned about the quality of your city or well water, the Home Master TMHP HydroPerfection Undersink RO water filter provides the best protection.

If you want to save money on a new under-sink RO system, we recommend the iSpring RCC7AK RO filter. It is cheaper than most RO filters but provides the same level of filtration performance.

A 5-stage filtration process removes over 1,000 contaminants, including dissolved solids, chemicals, and microorganisms.

The RCC7AK filter also includes a remineralization stage that enhances the taste of the purified water.

The only thing missing is a permeate or booster pump. So expect a somewhat low water flow rate.




RCC7AK features
1. 5-Stage Filtration

Five filters remove virtually all the dangerous contaminants in water from large particles of floating sediment to the tiniest germs.

Even chemicals like pesticides, pharmaceuticals, and VOCs are not spared. Heavy metals and dissolved salts are removed as well.

Three pre-filters– a sediment filter, a carbon KDF filter, and a carbon block filter – remove sediment, sand, chlorine, chloramine and other chemicals from the water before it reaches the RO membrane.

You may have noticed that the iSpring RCC7AK has two carbon pre-filters while most RO systems use just one carbon pre-filter.

Having the two carbon filters increases filtration performance.

The first carbon KDF filter does a great job removing large impurities and certain microorganisms. The second carbon CTO block excels at removing the smaller impurities that often affect the taste, odor, and appearance of water.

After the pre-filters, water passes through the 0.0001-micron RO membrane, where germs, heavy metals, and total dissolved solids are removed from the water.

An in-line carbon filter gives the water a final polish just before it comes out of the faucet.

2. Remineralization Stage

Because the purified water can taste a bit acidic, the iSpring RCC7AK RO system has a new stage that adds back stripped minerals to raise the water’s pH.

This results in water that tastes as fresh and natural as premium bottled water.

3. Easy DIY Installation

As with most under-sink RO systems, installing the RCC7AK is a 2-3-hour endeavor. But it’s not hard.

The system is designed for easy DIY installation with things like color-coded tubes to help you know which tube goes where and push to connect fittings to ease installation.

Everything you need is included in the package. It comes ready to install.


1. No Booster Pump

The iSpring RCC7AK RO system does not come with a booster or permeates pump.

So, the water pressure out of the faucet may be a bit low, meaning it will take longer to fill large water bottles.

The flow rate will be even lower if your home water pressure is already low. If that’s the case, consider buying a booster pump.

Another downside of not having an integrated pump is increased water wastage.

The RCC7AK drains about 3 gallons of water for every one gallon of purified water.



Although it’s a little bit slow to fill a water bottle or pitcher, the iSpring RCC7AK is still a great choice for families who are looking for an affordable but high-performance under-sink reverse osmosis filter.


Most RO systems in the APEC RO-90’s price range come with 6-month filters, meaning you need to replace the filters twice a year.

The RO-90 comes with 1-year filters, making maintenance easier and cheaper.

The high capacity is also handy for large families.




APEC RO-90 5 stage filtration
1. 5 Filters

Filtration begins with three pre-filters.

A sediment filter removes suspended particles, including dust, sediment, and rust.

Two carbon block filters follow, removing chlorine, chloramine, VOCs, pharmaceuticals, and other chemicals that affect the taste and smell of water.

This is the same double carbon filter setup in the iSpring RCC7AK system. But unlike the iSpring filter, the RO-90 uses similar carbon filters.

The result is the same – highly filtered water without a hint of chlorine or any other chemical taste or smell.

Next, the water passes through a 90 GPD FILMTEC RO membrane.

The membrane deals with the smallest and toughest contaminants, including bacteria, viruses, arsenic, fluoride, lead, and other dangerous impurities.

It also removes hardness minerals that cause scale.

An in-line carbon filter eliminates remnant odors and tastes just before the water comes out of the faucet.

2. High Capacity

The APEC RO-90 uses high-capacity filters that you don’t need to replace as often. Instead of the usual 6-month replacement frequency, the RO-90 pre-filters last for 12 months.

The RO membrane lasts even longer – around 2-3 years.

It’s a great choice for families that drink a lot of purified water. The RO-90 can handle the increased demand without requiring frequent maintenance.

3. Easy DIY Installation

It takes about 2-3 hours to install the APEC RO-90 RO system.

But at least you don’t have to hire a pro. The system is designed for DIY installation using the necessary tools.

Everything you need, including the filters, faucet, housing wrenches, and fittings is included.

The only extra tool you’ll need is a drill to make a new hole in the sink for the dedicated faucet.


1. No Booster Pump

The water flows out of the faucet is decent but not great. If you frequently fill large water bottles, it will take a while.

That’s because the RO-90 doesn’t come with a booster or permeate pump.

This also results in a higher water wastage to pure water ratio – around 3:1 compared to a 1:1 ratio for systems with an integrated pump.

The good news is that you can easily buy and install a booster pump later to increase water flow.

2. No Remineralization

This is not a major issue as it does not affect the safety and quality of the water – it’s just a matter of taste.

As I’ve already mentioned, purified RO water tends to be acidic, which can affect how it tastes. Some RO systems add the stripped minerals back to the water to restore that natural taste.

The APEC RO-90 lacks this remineralization stage.



We highly recommend the APEC RO-90 for large families and anyone looking for an affordable and low-maintenance reverse osmosis system.

If you are looking for the best deal, the iSpring RCC7 is an excellent choice.

It is one of the cheapest RO systems among our picks and yet it provides the same level of filtration performance as other pricier systems.

Of course, there are a couple of sacrifices you have to make.

There’s no booster pump, meaning the water flow rate is relatively low, and the system wastes more water.

The system also lacks a remineralization stage.




iSpring features
1. 5 Filters (with Dual Carbon Filters)

The filter setup in the RCC7 is pretty much the same as in the pricier RCC7AK. The only difference is the lack of a 6thremineralization stage.

But that’s not all that important anyway. The main filters are the ones that matter.

The RCC7 has the same dual carbon filters as the RCC7AK.

They include a carbon KDF filter that removes larger contaminants and a finer-micron carbon CTO block filter that targets impurities with smaller molecules such as chlorine and pharmaceuticals.

Together, the two carbon pre-filters remove dozens of chemicals and impurities that affect the taste, smell, and appearance of water.

There’s also a sediment pre-filter that removes suspended particles like rust, silt, and dust.

2. Easy DIY Installation

Color-coordinated tubings and push fittings make installation easier and quicker, though it still takes a good 2-3 hours to install the system under the counter and install a new faucet on the sink.

The instructions are very clear, and there are a few helpful videos on the manufacturer’s official website.

All the parts are included in the package. You don’t need to buy any extra fittings or parts.

3. High Quality Components

A lot of care and thought went into designing the RCC7 filter.

All components, including filters, tubing, and tank, are made from high-quality materials to guarantee performance and longevity.

The RCC7 filter has a WQA Gold Seal Certification, meaning it has achieved the highest industry standards.

One aspect we love about the filter’s design is the clear first stage housing, the part where sediment is captured.

You can see how much dirt has collected. This will give you an idea of how dirty your incoming water is and how long the filters are likely to last.

If the housing is almost full of sediment, then it’s probably time to replace the filters.


1. No Booster Pumps

If your home’s city water comes in at low pressure, I highly recommend buying a booster pump and integrating it into the filter.

Otherwise, the water flow is going to be too low.

But even in homes with good water pressure, the water flow is still not great since the filter lacks a booster or permeate pump.

The water wastage ratio is also reasonably high – 3 gallons of wastewater to 1 gallon of pure water.

But you can easily collect the drain water and use it for gardening.

2. No remineralization

If you love the taste of mineral water, get the RCC7AK RO filter instead. That’s the one with a remineralization stage.

The RCC7 system produces pure water with all minerals, even the good ones, stripped out.

It’s still healthy and safe for drinking but may taste a bit differently from bottled water.



If you love a good bargain, the iSpring RCC7 is hard to pass up. You won’t find a better deal at this price range.

Reverse osmosis filters have gotten pretty cheap in recent years. The Express Water RO5DX, 5 Stage RO system, is one of the most competitive available in the market.

If you are on a tight budget, it is the right choice.

It doesn’t sacrifice filtration performance – it’s still as good as other RO systems. It just lacks some extra features like remineralization and a booster pump.

The daily production rate is also relatively low – 50 gallons compared to 75 gallons from most RO systems.

But that’s still plenty of drinking water even for a big family.




Express Water RO5DX
1. 5-stage Filtration

Despite costing less than just about every other RO system in the market, the Express Water RO5DX provides the same high filtering performance.

The system consists of five filters, including three pre-filters, the RO membrane, and the post-filter.

First in line is the sediment pre-filter, which reduces water turbidity by removing dust, sediment, and any other suspended particles.

Then two carbon filters follow – a carbon CTO block filter and a granular GAC carbon filter.

This double carbon filter set up ensures that anything affecting the taste and odor of water is removed. This includes chlorine, chloramine, VOCs, and pesticides.

The RO membrane focuses on the hard-to-remove contaminants like fluoride, arsenic, lead, radium, and total dissolved solids.

The membrane also removes most of the microorganisms, including bacteria, viruses, and cysts.

Finally, an inline post carbon filter removes remnant tastes and odors that may have developed in the storage tank.

The post filter is located just before water comes out of the faucet so that you get fresh-tasting water.

2. 50GPD Capacity

Most under-sink RO systems have a daily capacity of 75 gallons with some going as high as 90 gallons.

The 50 GPD capacity of the Express Water RO5DX may seem low, but it’s still plenty for most families.

Adults drink about a gallon of water a day. So even for a large family, 50 gallons is more than enough for drinking as well as other uses like cooking and pets.

3. Leak Stop Valve Prevents Flooding

Because RO systems are typically installed under the sink, it’s easy for a leak to get worse without you knowing it.

You only discover it when it has grown into a flood.

The Express Water RO5DX comes with a mechanism to prevent this. If a fabric disk detects moisture on the floor under the sink, it automatically closes a valve to shut off the water.

4. Easy DIY Installation

It will take you quite a bit of time to install the Express Water RO5DX RO system, but it’s easy to work.

The part that takes up the most time is installing the new faucet on the sink. You have to drill a new hole if there isn’t already one on the sink.

The rest of the installation process is easy.

Tubes and parts are color-coded to let you know where everything goes. The fittings use a convenient push-to-fit installation system.


1. Frequent Filter Replacements

You have to replace the pre-filters every six months and the other filters every year.

In contrast, pricier RO systems require yearly replacements for the pre-filters and 2-3-year replacements for the membrane and post filter.

But this is a small sacrifice. And anyway, the filters are cheap and replacing them is quick and easy.

2. No Remineralization

The water comes out with a slightly unusual taste. That’s because all minerals have been stripped out.

Unlike some RO systems, the Express Water RO5DX doesn’t have a stage where some of those minerals are added back.

But most users don’t mind the taste, and they get used to it very quickly.



Just because it is cheaper than most doesn’t mean the Express Water RO5DX RO system is low quality.

It delivers the same high-quality purified water as other RO filters.

If you want pure RO water in your kitchen without spending hundreds of dollars, we highly recommend the Express Water RO5DX 5-stage RO filter.

If you are looking for an affordable RO system with a UV filter and a remineralization stage, we recommend the iSpring RCC7AK-UV.

The UV sterilizer adds extra protection against waterborne microorganisms, while the remineralization stage enhances the taste of purified water.




iSpring UV filter
1. 5 Primary Filters

The filter set up is pretty much the same as other RO systems: 3 pre-filters, a RO membrane, and a polishing post filter.

The pre-filters include a sediment filter, a granular KDF carbon filter, and a carbon CTO block filter.

The dual carbon filter increases filtration performance to ensure cleaner and better-tasting water.

The GAC filter deals with larger impurities while the CTO block removes chlorine, chloramines and other hard-to-remove chemicals.

The pre-filter not only clean up the water, but they also ensure sediment and chemicals don’t reach the RO membrane.

If they did, it would overload the membrane while chemicals like chlorine can damage it.

2. 11W UV Sterilizer

The 11W UV filter neutralizes any germs that pass through the RO membrane.

The UV lamp’s higher wattage (11W compared to 6W of most UV filters) makes it more potent against bacteria and viruses.

Unlike other UV lamps in RO systems, that remain on all the time, the UV filter in the iSpring RCC7AK-UV has an integrated flow sensor switch.  

The switch detects when there are water flowing and switches on the lamp.

Because the lamp comes on only when necessary, it uses less power and lasts longer.

3. Remineralization Stage

This stage restores the water’s natural alkalinity (pure RO water tends to be a bit acidic) and taste.

Red mineral stone adds back little amounts of calcium, magnesium, and other minerals to the pure water to restore its natural taste.

Calcite increases the water’s pH to make it alkaline.

The result is healthier and more natural tasting water.

4. Easy DIY Installation

Color-coded tubes and push tubing make installation easy, though not necessarily fast. It still takes at least two hours to install the system under your sink.

Everything you need is in the package including a brass adaptor for either 3/8” or 1/2″ outlets and a brass faucet.

The instruction manual is well written and is easy to follow. If you need more help, there are several installation videos on the manufacturer’s website.

You can also contact iSpring’s customer support. Their customer service is excellent.


1. No Booster Pumps

The water flows out of the faucet is decent but not strong. If you have low water in your home, the flow rate from the RO system will be even lower, and there will be more water wasted.

Like most RO systems, the iSpring RCC7AK-UV doesn’t come with an integrated booster pump. Consider buying one and installing it if the purified water comes out in a trickle.



The iSpring RCC7AK-UV provides a couple of extra important features at a surprisingly affordable price tag.

You can enjoy great tasting alkaline water without having to spend a lot of money on a high-end RO system.



If you love the taste of mineral water, the APEC ROES-PH75 is the best choice. In addition to filtering water, it adds calcium to the water to raise the water’s pH and replace lost minerals.

The resulting purified water is slightly alkaline – which is healthier for you – and tastes better than non-mineralized RO water.




1. 5 Filters with Dual Carbon Stages

There are five primary filters plus the alkaline filter.

The primary filters include three pre-filters, a RO membrane, and a post filter.

Water first passes through the pre-filters where a sediment filter removes large suspended particles like silt, and double carbon filters remove chemicals that cause unusual odors, tastes, and cloudiness in water.

These include chlorine, VOCs, pesticides, and pharmaceuticals.

At the heart of the system is a high rejection that removes 99% of total dissolved solids, including arsenic, lead, radium, fluoride, bacteria, and viruses.

After passing through the RO membrane, the water goes into the reserve tank. By the time you turn on the faucet, the water may have absorbed new smells and tastes from the tank.

A coconut shell refining carbon filter located inline just before the faucet removes these remnant odors and tastes to make sure you get fresh tasting water every time.

2. Alkaline Filter

The sixth stage of the ROES-PH75 system is the alkaline filter containing high-quality USA-made calcite.

This filter adds calcium carbonate to the water, restoring the natural mineral taste the RO membrane stripped out.

It also increases the water’s alkalinity. Alkaline water has been shown to have some health benefits.

Now, don’t expect a drastic change in your water’s pH. The ROES-PH75 is not an alkaline water machine. It only increases alkalinity slightly.

Most of the people who tested the water from the faucet got a figure in the high sevens, which is as good as it gets.

Depending on the original pH of your water, you might even get a pH result below 7.

If you want guaranteed alkaline water, we recommend the Express Water ROALK10DCG 10-stage RO system that we’ve reviewed below.

But even it does not come close to what you’d get from an alkaline water machine.

3. Ideal for Large Families

The APEC ROES-PH75 RO filter can produce up to 75 gallons of purified water per day.

That’s plenty of water for most families. If you use pure RO water for more than just drinking – e.g., cooking, beverages, pets, etc. – the ROES-PH75 produces more than enough for your needs.


1. Plastic Connectors

Our main gripe with the ROES-PH75 is the plastic connectors it comes with. They don’t feel flimsy, but they are still not as durable as metal connectors.

Some buyers decided to buy their metal connectors.

If you decide to use the provided plastic connectors, be careful when fitting them. Do not overtighten as that could weaken or break them.



If you are looking for a RO system to replace your bottled water purchases, the APEC ROES-PH75 is an excellent choice.

The water tastes just as good, if not better than bottled water.

As a bonus, you don’t have to worry about adding more plastic waste to the environment.



The Express Water ROALK10DCG 10-stage RO system is ideal for those looking for an affordable RO system that produces mineral alkaline water.

Reviews are mixed as to how much the system raises water alkalinity with some customers reporting a big difference in taste and pH, and others only a slight change.

This is probably due to differences in the original pH of the water. It can affect the final pH and alkalinity.

What most customers agreed on is that the system produces ultra-clear and great tasting water.




Express Water RO system
1. 5-Stage Filtration

The ‘10-stage’ product description can be a bit misleading. In reality, there are only five filters. The other five stages are within the alkaline filter.

These primary five stages are the ones that matter most as this is where contaminants are removed.

The sediment pre-filter removes dust, rust, and silt. Two carbon filters (CTO carbon block and granular activated carbon) remove chemicals such as chlorine, chloramines, and VOCs.

Then a RO membrane removes total dissolved solids such as fluoride, hardness minerals, lead, and arsenic.

The final stage, the post-carbon filter, comes after the alkaline filter. It refines the water, removing any remnant tastes and odors just before it comes out of the faucet.

2. 5-Stage Alkaline Filter

No other RO system has a more elaborate remineralization stage as the Express Water ROALK10DCG 10-stage filter.

Water passes through 5levels of remineralization, with each level adding an active mineral to the water.

This mimics how spring water picks up minerals from the rocks.

The resulting water has a higher pH and alkalinity. It has a sweeter more natural taste compared to non-mineralized RO water.

The actual final pH will vary depending on your water chemistry.

Some users got a pH as high as 8.5 while others measured a pH just above 7.

Note: If you are using a TDS meter, you’ll get a higher reading compared to other RO systems because of the added minerals.

3. High Daily Production Capacity Provides More than Enough Water for Large Families

The Express Water ROALK10DCG has the highest daily production capacity of any RO system we have reviewed.

It can produce up to 100 gallons per day.

It’s a great choice for large families.


1. Takes Time to Install

While the Express Water ROALK10DCG is designed for easy DIY installation, but it takes time to set up, at least 2 hours, and sometimes more if you have not used such DIY projects before.

But the color matching system helps speed things up. You can tell at a glance where a part goes.



If you’d like to start taking alkaline water but find alkaline water machines to be too expensive, the Express Water ROALK10DCG 10-stage RO system is a cheaper alternative.

It’s not as good as a dedicated alkaline water machine, but it produces healthier and better-tasting alkaline water compared to most RO system

If you want a temporary RO system or an RO filter you can take with you when traveling, we recommend the APEC RO-CTOP-C.

It is a compact portable RO filter that sits on the countertop, rather than under the sink as most RO systems do.

It installs in standard faucets in minutes, making it ideal for use in hotels, Airbnb rentals or a friend’s house.

It’s also a great choice for places like apartments, motor homes, dorm rooms, and retirement homes where installing an under-sink RO system might not be possible.

Despite the filter’s size, it filters water just as well as bigger systems and has an impressive 90 GPD production capacity.




1. 4-Stage Filtration

Here are the four filters water passes through.

Sediment filter: Removes dust, sand, rust, and other suspended particles.

Activated carbon filter: Removes various chemicals, including chlorine, VOCs, and certain pesticides.

RO membrane: Removes microorganisms, heavy metals, fluoride, and other dissolved contaminants.

Post carbon filter: Removes any remnant odors and tastes before the water comes out of the faucet.

2. Easy Countertop Installation

This is one of the easiest RO filters to install.

You don’t have to crawl under the counter or drill a hole in your sink for a new faucet. It takes just a few minutes to attach to the existing faucet.

The system is compatible with most standard faucets. It comes with several adaptors for different faucet types and sizes.

If one adaptor doesn’t fit, try another.

Note that the RO-CTOP-C filter is not compatible with pull-out, sprayer, or custom size designer faucets.

3. Ideal for On-the-Go Use

If you spend a lot of time in hotels or vacation rentals, this is the perfect filter to ensure you have access to clean, safe water wherever you are.

The RO-CTOP-C comes with a case for easy carrying and takes a few minutes to set up in a hotel room.


1. Low Water Flow Rate

The RO-CTOP-C is convenient in so many ways – it’s super easy to set up, no plumbing is needed for its installation, and you can carry it when you go on vacation.

But it can be frustrating to use. The purified water comes out in a trickle. It could easily take more than an hour to fill a 5-gallon bottle.

The reason for the low flow rate is that the RO-CTOP-C has no reserve tank. Without a holding tank, you get water directly from the filters when you turn it on.

Because water passes slowly through the different sets of filters, it also comes out slowly.

If you are using the filter at home or in an RV, the trick is to fill large bottles for future use. That way, you can quickly access drinking water whenever you need it.



For those who don’t look forward to the hassle of installing an under-sink RO system or don’t have the space to do so, the APEC RO-CTOP-C provides an easy and affordable solution.

You’ll also love it if you own an RV, boat or spend many of your days in hotel rooms.

If you have limited space under the sink but don’t want to get a low-flow countertop RO filter, consider getting the Whirlpool WHER25 RO system.

The system uses a 3-stage filtration process that reduces the number of filter canisters you need to fit under the sink.

But the space-savings come at a cost.

The daily water capacity of this filter is much lower than most RO systems (just 18 gallons a day), and the filter life is not as long as other RO filters especially for homes that receive water with a higher level of contaminants.

But in terms of filtering performance, which is what matters most, the Whirlpool WHER25 is just as good as other RO filters. It removes the same dangerous contaminants as any other RO system.




Whirlpool RO System
1. 3-stage Filtration

Most RO systems have at least five stages of filtration. The Whirlpool WHER25 has only three.

Sediment pre-filter: This filter catches the large particles suspended in water, including sand, rust, and silt. This clears up the water and prevents these particles from clogging up the RO membrane.

RO-membrane: Removes lead, arsenic, nitrates, cysts, chromium, and other contaminants.

Activated carbon post-filter: Removes odors and tastes to make sure you get fresh water.

The main difference between the Whirlpool WHER25 and other RO systems is the lack of a carbon pre-filter before the RO membrane.

While this does not affect filtering performance by much, it reduces filter lifespan since the filters have to deal with a higher contaminant load.

2. Filter Replacement Indicator

The faucet has a battery-operated filter replacement reminder indicator. It will come on when it’s time to replace the sediment and carbon filters.

However, many users found it better to buy a TDS meter and monitor the water themselves.

The faucet tracks time, not the number of gallons or the TDS levels.

Depending on your water quality, you might replace the filters too early, and throw away perfectly good filters, or too late, which could damage the semi-permeable membrane.

3. Easy Filter Replacement

The filters in the Whirlpool WHER25 are some of the easiest to replace.

They have the same modular design as Home Master RO systems. You replace the filter and the filter housing at a go.

It takes just a few seconds to unscrew the old filters and put new ones back in.

There’s no need to touch wet, dirty filters or sanitize the filter housings.


1. Frequent Filter Changes

At their best, the sediment pre-filter and the carbon post-filter last only six months. If you use well water or lower quality municipal water, the filters can last as little as three months.

The RO membrane normally lasts two years, but you might need to replace it months earlier if your water quality is not very good.

Many users say they spend over $100 a year on filter replacements. That’s relatively expensive maintenance.

The main problem is the 3-stage filtration system. Because each filter has to handle more contaminants, they last for a shorter period.

The RO membrane is especially at risk of damage from chlorine and other chemicals that are generally caught by a carbon pre-filter.

2. Low Daily Water Capacity

At its optimal performance, the Whirlpool WHER25 only manages 18 gallons a day.

Most budget RO systems can produce at least 50 GPD. The Whirlpool WHER25’s capacity is underwhelming, making it only ideal for small and average size families. 



While it does come with a few sacrifices, the Whirlpool WHER25 3-stage RO system is still a solid choice for homes that don’t have space for a large 5-stage system.

But we only recommend it if you receive high-quality municipal water. Do not use it with well water to avoid high maintenance costs.

If you can, also consider installing a whole-house carbon filter to reduce the contaminant load on the RO system.

One of the main downsides of reverse osmosis systems is that they waste water, sometimes a whole lot of it.

The least efficient filters drain 4 gallons of water to every gallon of purified water.

Those that are more efficient require a permeate or booster pump. You usually have to buy it separately since most RO systems don’t come with one.

The Brondell RO Circle RO filter wastes only 2 gallons of water for every gallon of purified water. It does this without requiring a booster pump.

Instead, it uses a special valve to reduce back pressure on the RO membrane, which is what causes high wastage in other systems.




portable ro water filter
1. 4 Filters

The Circle RO system uses a set of four filters to remove a wide range of contaminants, including heavy metals, hardness minerals, cysts, and chemicals.

Similar to most RO systems, the Circle starts with a sediment pre-filter for dust and silt and a carbon pre-filter for chlorine, VOCs and other soluble chemicals.

The two pre-filters remove a large portion of impurities from water, which protects the semipermeable membrane from clogging or getting damaged.

The RO membrane, at the core of the system, filters out the hard-to-remove impurities like heavy metals, microorganisms, and dissolved minerals.

Finally, a carbon post-filter removes any remnant smells and tastes before the water flows out of the faucet.

2. Water-saving Design
flexible reserve tank

Brondell has made two critical changes to the standard RO system design to reduce water waste.

The first is a patented Smart Valve.

It reduces back pressure from the reserve tank on the RO membrane, thus allowing more water to come in and less to go down the drain.

The second is a flexible reserve tank.

Water is held in something that looks like a balloon that expands and contracts to depend on the amount of water it’s holding.

Since back pressure is created when the reverse tank is partially filled, So, Brondell has designed the flexible reservoir that will contract and thus remain full, when you draw water from the faucet. 

This reduces back pressure.

As more water comes in, it expands to its maximum capacity.

These two changes also increase the water flow rate.

The faucet fills up your water bottles faster than most RO systems.

3. Stylish Modern Design

It’s not just the internal components that are different; the entire design of the Brondell Circle is unique.

Instead of having the reserve tank and filter cylinders separate, everything is contained in a stylish modern box.

The manufacturer claims that it’s a space saving design, but only if you consider the horizontal space.

Vertically, it’s fairly high. It’s a tight fit under most sinks. Some users had to leave it on its side as that’s the only way it could fit.

4. Easy Maintenance

Filter replacement is super easy, and there’s even an LED reminder in case you forget to replace the filters.

But we strongly recommend getting a TDS monitor. The reminder measures time. It will alert you to change the pre-filter and post-filter every six months.

But because water quality differs from home to home, you might change your filters too early or too late.

With a TDS monitor, you can check when TDS levels begin to go up and replace the filters.


1. Expensive Filters

Maintaining the Circle RO system will cost you quite a bit.

A set of replacement filters costs about $60, and you need two sets every year.



The Brondell Circle RO system stands out not only for its unique – and stylishly modern – design but also for its water-saving technology.

It’s a great choice if you are looking for a reverse osmosis system that wastes less water without using a booster pump.


Best Whole House Reverse Osmosis System

Most of the RO systems in the market are designed for under-sink installation. If you want to supply RO water to your entire home, you’ll have a harder time finding a whole house reverse osmosis system. 

In fact, our whole house RO system recommendation – the iSpring RCS5T – isn’t actually a whole house system. It’s a light industrial/commercial reverse osmosis system. 

But with the addition of a holding tank and pump, it can supply water to your entire home. 




1. 5-Stage Filtration

The iSpring RCS5T has the same 5-stage filtration process as the smaller under-sink iSpring RO systems. They include a sediment filter, two carbon filters, a reverse osmosis membrane and a carbon post-filter. 

The RO membrane has a unique dual flow design that draws water from both sides. This allows the membrane to process a bigger volume of water, which increases overall flow rate. If you’ve connected the system to a holding tank, it’ll fill up pretty quickly. 

2. High Daily Capacity

Considering the average household uses about 300 gallons of water a day, the 500 GPD capacity of the iSpring RCS5T should easily meet the needs of most families. 

That said, we don’t recommend connecting the system to your home’s entire plumbing. The RO membrane has a capacity of just 2,600 gallons. You don’t want to waste it on toilet water or showering. 

RO water is best for drinking and cooking. Ask your plumber to set it up such that it supplies water only to sink faucets, the refrigerator, and other appliances such as an icemaker. 

3. Booster Pump

The iSpring RCS5T is designed to work primarily as a tankless system. You turn on a faucet and the system purifies the water immediately and it comes out of the faucet. 

The iSpring RCS5T is able to provide purified water on demand because it has an electric booster pump that increases water flow rate through the filters. The dual flow design of the RO membrane also helps.

Note that the on-demand supply of RO water works only when you are using the iSpring RCS5T as a point-of-use RO system. That is, you connect it only to the included faucet. 

If you plan to connect it to multiple faucets and appliances, you’ll need to buy a holding tank. 


1. Additional Components Needed

To have the iSpring RCS5T supply RO water to several parts of the house, you’ll need to buy a non-pressurized holding tank and a pump. 

The tank holds purified water so you can get it whenever you want without waiting. The pump ensures water from the tank reaches all faucets with adequate pressure. 

Note: If you want a ready-to-use whole house reverse osmosis system, we recommend the Crystal Quest 7,000 GPD whole house RO system. It costs thousands of dollars, but comes as a full package complete with a tank and booster pump. There’s also a cheaper 1500 GPD whole-house system

2. Short Filter Life

For a RO system designed for use in large homes, hotels and businesses, the iSpring RCS5T has a limited filter life. 

The RO membrane lasts only 2,600 gallons. Depending on how much RO water you use at home, you may find you need a new set of filters every month. That’s why we recommend connecting the system to certain faucets only, not the entire house.



The iSpring RCS5T RO system is a great choice if you want a high-capacity reverse osmosis system that can supply purified water to several points of use in your home. 


Why Do You Need a Reverse Osmosis Water Filter?

Express Water alkaline RO System

Standard active carbon filters do a great job removing chlorine, chloramines and other chemicals from water.

But they don’t provide complete protection since they do not filter out most heavy metals, dissolved solids, and harmful microorganisms.

A carbon filter is okay for washing or cooking water. But for drinking water, a reverse osmosis filter is the best.

It removes almost all contaminants from water, resulting in clean and safe drinking water.

Even if you have a whole home water filtration system in place, it’s still a good idea to have a point-of-use RO system to filter drinking water.

We also recommend a RO filter for homes that receive treated city water.

That’s because the water, though treated, may still contain some germs as well as heavy metals, chemicals, and other impurities.

If you use well water, a RO filter is even more important.

It will remove microorganisms, dissolved impurities, and hardness minerals.

What are the Benefits and Risks of Drinking RO Water?

The advantages of drinking RO water are obvious – the water is safe and healthy. Reverse osmosis does a great job removing the most dangerous water impurities including germs, chemicals and heavy metals. 

A RO system also removes hardness minerals from water, which reduces scale formation in your appliances. That’s why it’s a good idea to hook up your icemaker to the RO system. Not only will you get better quality ice, your ice maker will also last longer. 

You can also use RO water in your coffee maker, water heater and other small appliances to extend their lifespan. 

The main concern some people have with reverse osmosis water is the lack of healthy minerals. The semi-permeable membrane strips the water of all minerals, including healthy ones like calcium, magnesium, iron, and potassium. 

However, most people in the US don’t get most of their essential minerals from drinking water. If you are eating a healthy balanced diet, you are already getting all the minerals your body needs. 

So, unless you are malnourished, the lack of minerals in RO water shouldn’t be a problem. 

In any case, drinking water with harmful impurities like microbes and arsenic carries more risks for your health compared to the absence of a few minerals that you can easily get from other sources.  

If you are still concerned, get a RO system with a re-mineralization filter. This filter is positioned as the last stage in the system. It adds healthy minerals back into the water. 

A RO filter with a re-mineralization stage also solves another common concern with RO systems – the taste of water.  

Some people say RO water has a flat taste. Others describe a sour or metallic taste. You’ll especially notice the change in taste if you’ve been drinking tap water or bottled mineral water. 

The taste of RO water is because of the lack of minerals and reduced pH. If your RO water tastes metallic, that’s a sign it is slightly acidic. 

A re-mineralization filter improves the taste of water – making it sweater and earthier – and raises its pH. Alkaline water not only tastes better, it’s also better for your health. 

Note: If your RO system doesn’t have a mineral filter, you can buy one and connect it to the system. Alternatively, buy liquid minerals and add them to your drinking water. 


Reverse Osmosis System Buying Guide

Though all RO water filters work using a similar mechanism, there are significant differences between different brands and models.

Certain RO systems excel at removing particular contaminants. Some are ideal for larger families, while others are perfect for RV and boat owners. 

You also have to consider things like water flow rate, waster waste ratio, maintenance requirements, and remineralization.

So, choosing the right RO filter is not quite as simple as finding the cheapest or most popular.

Here’s what to consider to ensure you buy the right reverse osmosis system for your needs.

1. Water Output

Water output is provided in GPD or gallons per day.

For most homes, a 50 GPD RO system is enough for their drinking water needs. If you have a larger family or want a high-output system, look for a 90 or 100 GPD RO unit.

Note that the daily water output will be affected by factors like water temperature, quality, and pressure.

Typically, your system’s GPD will be lower than the stated one.

2. Number of Stages

The number of stages indicates a system’s performance and capability. The best RO units will have 5-7 stages, with some of those stages being for remineralization.

Cheaper RO systems have 3-4 stages. They are good at filtration but lack remineralization.

3. Permeate or booster pump

A built-in permeate pump reduces back pressure, which increases the flow rate and reduces water wastage.

Most RO filters don’t come with a permeate pump. But you can buy an electric booster pump separately and connect it to the system.

It’s especially helpful for homes with low water pressure.

4. Filter Lifespan

Most RO filters last 6-12 months.

12-month filters such as those used in APEC and Home Master systems generally tend to be of better quality and perform better at removing contaminants.

They are usually pricier, but this is canceled out by the extended replacement period.

6-month filters are also good quality, but you have to be careful to replace them at the right time. Otherwise, you could damage or clog the sensitive semi-permeable membrane.

They may be cheaper, but you have to buy two packs a year.

Note that the 6-12-month lifespan is just for the pre-filters and the carbon post-filter.

The semi-permeable membrane in most RO systems lasts 2-3 years.

5. Remineralization stage

If you love the taste of mineral water, look for an RO system with a remineralization filter. It adds backs some of the stripped minerals, usually calcium and magnesium.

A remineralization filter also raises the water’s pH, making it neutral or slightly alkaline.

If you are concerned about drinking acidic water, make sure the RO system has a remineralization filter.

6. Water Efficiency

You’ll come across rations like this when comparing RO systems –4:1, 2:1, 1:1, and so on.

What do these ratios mean?

It’s wastewater to pure water ratio that indicates the efficiency or wastefulness of the system.

A 4:1 ratio means four gallons of water are drained for every one gallon of pure water that you get from the faucet.

The most efficient RO systems, usually those with a permeate pump, have a 1:1 ratio. The most wasteful ones have a 4:1 ratio.

Note: That water doesn’t have to be wasted. You can collect it and use it for gardening.

7. Reserve Tank Size

Most RO systems come with a standard 4-gallon reserve tank, of which 3.2 gallons are usable.

But you can upgrade to a larger reserve tank to meet your needs. Keep in mind, however, that a larger tank will take up more space and may not fit under the sink. 

8. Water Flow Rate

Most RO systems produce a weak stream of water from the faucet.

If you’d like a unit with a higher flow rate, look for one with an integrated permeate pump. Alternatively, buy one without the pump and get a booster pump separately.

The Brondell RO Circle RO system is also the right choice. It doesn’t have a permeate pump but still has a decent flow rate.

It uses a special valve and reserve tank design to increase the flow rate and reduce waste wastage.

How Do Reverse Osmosis Systems Work?

reverse osmosis filter

RO systems consist of two crucial elements: a set of filters and a pressurized reserve tank. 

The filters remove impurities from the water while the tank stores the purified water until you need it. 

Of course, there are additional smaller components such as fittings, tubes, a drain saddle, and a faucet. You can also add other components yourself such as a booster pump, a UV filter, and so on.  

Below is a more detailed explanation of the different filtration stages in an RO system. 

Reverse Osmosis Water Filter Stages Explained

For the best filtration performance and to increase the lifespan of the RO semi-permeable membrane, RO systems consist of multiple filters or stages. As water passes through each stage, specific impurities are removed. 

Here are the 5 stages of a standard reverse osmosis system. 

1st Stage: Sediment Filter

Water first passes through a sediment filter that traps large particulates like sediment, rust, sand, algae and dust. A sediment filter is especially important if you use well water, as it tends to contain a higher level of particulates. 

Most RO systems use a see-through sediment filter cartridge, so you can see when filter media gets clogged and dirty and needs replacing. You typically have to replace the sediment filter every 6 to 12 months depending on how much RO water you use and how dirty your water is. 

2nd and 3rd Stages: Carbon Filters

After the sediment filter, two carbon filters remove chemicals in the water. These include chlorine and chloramines, as well as more harmful chemicals like pesticides, VOCs and pharmaceuticals. 

Removing these chemicals not only eliminates unpleasant tastes and odors in the water, it also protects the semi-permeable membrane. Chlorine is especially damaging to the RO membrane and can reduce its lifespan. 

The reason most RO systems use two carbon filters is to ensure as many chemicals and impurities as possible are removed before the water reaches the RO membrane. Some systems combine a GAC (granular activated carbon) filter and a carbon block filter  

GAC filters have lower filtration efficiency but have high water flow rates. Carbon block filters have a slower flow rate, but they do a better job removing contaminants. 

The typical replacement period for the second and third filters in a RO system is 6-12 months. 

4th Stage: RO Membrane 

At the heart of any reverse osmosis system is a semi-permeable membrane that blocks almost everything except water molecules. 

At this stage, all impurities that have made it past the sediment and carbon filters – these include minerals, salts, microbes and heavy metals – are trapped by the RO membrane. 

After the RO membrane, the now-pure water goes into the pressurized reserve tank.

5th Stage: Carbon Post-filter

The final stage is usually an inline carbon filter located between the reserve tank and the faucet. When you turn on the faucet, water passes through this filter. 

The post filter eliminates any tastes and odors the water may have gotten while sitting in the tank.  

Additional Stages

Not every reverse osmosis system has five filtration stages. Pricier systems come with 6 or 7 stages. 

Some include a re-mineralization or alkaline filter that adds back healthy minerals to the water to make it taste better and increase pH. 

Some RO systems also have a UV lamp that kills any microbes that pass through the RO membrane.  

Optional Accessories & Upgrades For RO Systems

Reverse Osmosis filters

A RO system will come with everything you need to set it up and get purified water.

But you can make upgrades to improve water flow, increase water storage, help with maintenance, and enhance overall performance. Here are the best upgrades to consider

Accessories to Improve Water Quality

TDS Meter

Handheld TDS Meter

The filter replacement period provided by the manufacturer is just an estimate based on specific conditions.

Depending on your water quality, you may need to replace your filters sooner or let them last a couple of months longer.

The best indicator of water quality is the level of total dissolved solids (TDS).

With a handheld TDS meter, it’s easy to monitor your water quality and determine the best time to replace the filters.

Get a reading immediately after you install the RO system. Then take a reading once a month after.

If TDS levels start to rise, it’s time to get new filters.

Water Test Kit

If you are concerned about levels of a certain impurity like lead, iron, chlorine or scale, get a water test kit that tests for that specific contaminant.

Take a measurement right after installation and get regular readings afterward.

UV Filter

A UV filter provides extra protection against microorganisms. It works by directing high-intensity UV radiation towards germs.

This damages their DNA, preventing the microorganisms from reproducing or causing any harm in the body.

If your RO system comes with a built-in UV filter, you don’t need this upgrade.

Accessories to Increase Efficiency

Permeate or Booster Pump

Most RO systems have a weak flow rate, making it tedious to fill a large water bottle or pitcher.

Adding a permeate or booster pump can increase water pressure. It’s especially helpful if your home already suffers from low water pressure.

A booster pump also reduces the amount of water wasted by reducing the effect of back pressure.

If your RO system already has an integrated permeate pump, you don’t need this upgrade.

A Bigger Storage Tank

A typical RO system comes with a 4-gallon reserve tank with a usable capacity of 3.2 gallons.

If you have a large family or use purified water for more than just drinking, consider upgrading to a bigger tank.

APEC, one of the best-known manufacturers of RO filters, sells a 14-gallon tank (10 gallons usable) that is perfect or large homes and offices. 

Shutoff Valve

The main reason why many RO filters send a lot of water down the drain is back pressure.

When the pressurized reserve tank gets close to filling up, water has to work harder to get into the tank, leading to more water getting wasted.

A shutoff valve turns off the water flow into the tank when tank pressure matches the pressure of the incoming water.

This reduces the amount of water wasted.

Functional Upgrades

Ice Maker Kit

Purified water produces better quality ice compared to normal tap water.

An ice maker kit allows you to direct purified water directly from your RO system to the refrigerator or ice maker.

The kit consists of tubing, quick-connect fittings, and a shut-off valve.

Connectors and Adaptors

If you don’t like the plastic fittings included with the RO filter, you can upgrade to brass connectors and adaptors that are guaranteed to last longer.

You can also buy quick-connect fittings if your RO system doesn’t come with them. They make installation and maintenance so much easier.

Drain Adapter

Instead of drilling a hole in your drain line for the drain saddle, you can use a drain adapter. The adapter connects to the dishwasher drain inlet.

Style Upgrades

Designer Faucet

If the standard chrome faucet looks out of place in your kitchen, most RO manufacturers sell designer faucets in different finishes such as brushed nickel, oil rub bronze and brushed stainless.

You can also swap the standard faucet for an air gap faucet if your plumbing needs one.

What Do Reverse Osmosis Systems Remove?

Express Water alkaline RO System

The following are the impurities removed by the semi-permeable membrane.

In addition to these contaminants, sediment and carbon pre-filters remove turbidity (sediment, rust, and dust), chlorine, pesticides, VOCs and various chemicals.

RO Terms You Need To Know

RO system

Stages: These refer to the filters in the RO system, including the remineralization filter if there’s one. A 7-stage RO system has seven filters that water passes through.

Storage tank: The reserve tank that stores purified water for on-demand use.

Water output: The amount of water the RO system can produce in 24 hours. This ranges between 40 gallons and 100 gallons for different RO systems. Under regular use, most RO systems provide less water than the stated output.

Wasted water: The water that’s wasted by the RO system. This is the water used to flush the semi-permeable membrane. It goes down the drain.

pH (acidic or alkaline): The acidity or alkalinity of purified water. Pure RO water tends to be slightly acidic because it is stripped of minerals. Look for a RO system with a remineralization stage if you want alkaline or neutral pH mineral water.

TDS: The concentration of substances dissolved in water. TDS includes salts and minerals such as calcium, magnesium, nitrates, sulfates, and chlorides. TDS levels are a good measure of water quality and pure RO water has a low level of TDS.

Air gap faucet: A faucet that prevents the drained water from flowing back into the RO system. 

Most RO systems come with a standard faucet, which is easier to install and works well enough.

Reverse Osmosis System Installation

apec top tier 5-stage

Under-sink RO systems take 2-3 hours to install.

Installation involves connecting it to your cold-water feed, directing the wastewater to the drain line and installing the new faucet on the sink.

Before you begin the installation, check what kind of faucet the RO system comes with.

If it’s an air gap faucet, you’ll need to drill a 1½-inch hole in the sink. If it’s a standard faucet, which is what almost all RO systems use, you’ll need to drill a hole ½” to 5/8” wide.

Make sure you have the right drill for the job. Also, have on hand some Teflon tape and a pair of scissors to cut the tubing.

Check that all the parts are there, including fittings and filters.

Here’s how to install a reverse osmosis system, step by step.

  1. Turn off the cold-water line and turn on the cold-water faucet to drain it. Then disconnect the cold-water feed line.
  2. Attach the T connector to the cold-water feed pipe. Connect the cold-water line and the RO tube to the T connector.
  3. Install the drain saddle. This will require drilling a hole on a section of the drain line and then mounting the drain saddle over it. Alternatively, you can use a drain adaptor if you don’t want to drill a hole in your drain line.
  4. With the water inlet and drain set up, it’s time to mount the filters. If the filters are not yet assembled, do so before mounting them on the side of the wall or the back wall. Some filters don’t need to be mounted – you can place them on the floor.
  5. Position the reserve tank on the floor under the sink. If you don’t have enough vertical space, you can place it on its side.
  6. Drill a hole for the faucet on the sink and install the faucet if there’s already an extra hole on your sink, no need to drill a new one.
  7. Connect all the tubing. Most RO systems use color-coded tubes, so you know exactly where each goes.
  8. If your system has a UV filter, plug it in.
  9. Turn on the cold water and check for leaks.

Before you can drink the water, let the reserve tank fill up 3-4 times, emptying it every time. You can then drink the water.

Reverse Osmosis System Maintenance

ro installation

RO systems don’t require much in terms of maintenance. You need to regularly check for leaks and replace the filters at the right time.

Filter life ranges from 6-12-months though some units can have a filter life as short as three months.

To make sure you replace the filters at the right time, get a TDS meter to monitor water quality.

As soon as you notice TDS levels going up, get new filters.

The RO membrane lasts for 2-3 years.

Frequently Asked Questions About RO Systems

reverse osmosis system reviews

Is it okay to drink reverse osmosis water?

Reverse osmosis water is clean, safe, and devoid of most impurities, including waterborne bacteria and viruses.

It’s the best water for drinking.

Some people worry that it is unsafe because it is mineral-free. However, mineral-free water is not harmful to your body. You get most of your essential minerals from food, not water.

If you are still concerned, consider buying an RO system with a remineralization filter.

How does reverse osmosis work?

A reverse osmosis system works by forcing water through a semi-permeable membrane. The membrane blocks virtually everything but water molecules.

The RO membrane and pre-filters remove a wide range of contaminants, including microorganisms, chemicals, and total dissolved solids.

What is not removed by reverse osmosis?

An RO membrane does not remove certain chemicals with molecules smaller than those of water. These include some pesticides and herbicides. It may also let some chlorine through.

That’s why all RO systems have carbon pre-filters that are much more effective at filtering out these chemicals.

How much water is wasted with reverse osmosis?

It depends on the efficiency of the system. The least efficient RO systems waste 4 gallons of water for every 1 gallon of purified water.

The most efficient filters waste only 1 gallon for every gallon of drinking water.

RO Water vs. distilled water: which one is better?

Reverse osmosis water is better than distilled water. That’s because distillation does not remove all chemicals, including chlorine and chloramines.

Reverse osmosis removes almost all kinds of contaminants.

How do I connect my RO system to my fridge or ice maker?

You’ll need to buy a refrigerator or ice maker kit, which most RO manufacturers sell separately. You can then run a tube carrying purified water from the RO system to the ice maker.


water osmosis systems

Reverse osmosis is the best and most reliable method of filtering drinking water. It protects from almost all kinds of impurities.

The Home Master TMAFC-ERP Artesian RO System is our top recommendation.

It has everything you need in a high-quality RO system plus some extras like the permeate pump and the remineralization stages.

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