Express Water ROALK10DCG 10-Stage Reverse Osmosis System Review

Express Water ROALK10DCG



If you want an RO system that produces mineral alkaline water, we recommend the Express Water ROALK10DCG 10-stage reverse osmosis filtration system.

You might be a bit skeptical about a ’10-stage’ RO system. I was too. Does it have ten filters?

The ’10-stage’ label is true though it’s also a bit of marketing speak. In reality, the Express Water system has five filters that do actual water filtration.

The other five stages are for remineralization.

No other RO system has such a comprehensive remineralization process, which is why the Express Water ROALK10DCG is the best choice for those who prefer drinking mineral alkaline water.

Read on for our full review.

If you are looking for a more basic RO system without all the extras, get the best recommendations in our reverse osmosis water filter buying guide.



Product Specifications


Filtration System Design

RO5DX 5 stage mineralization

The Express Water 10-stage system has two distinct sections.

The first is the main filtration section consisting of 5 filters. These include three pre-filters, the RO membrane, and the post-filter.

The second is remineralization section consisting of 5 stages. As water passes through each of these stages, a specific mineral is added to replace the ones stripped out by the membrane.

That’s where the ’10-stage’ label comes from – 5 for filtration and 5 for remineralization.

Here’s a closer look at the different filters.


There are three pre-filters the water passes through before it reaches the RO membrane.

The pre-filters remove contaminants that can damage or clog the membrane.

The first pre-filter is for sediment. It targets the larger particles that you can see, such as silt, dust, and sand. These impurities are the major causes of water discoloration.

If you use well water, your water is going to have particularly high levels of sediment. The sediment filter ensures all that dirt doesn’t clog the carbon filters and RO membrane.

The next two pre-filters are both carbon filters. But they are not similar.

One is a granular activated carbon (GAC) filter. It absorbs chemicals like chlorine and filters out fine sediment that may have passed through the sediment filter.

The other one is a carbon block filter that removes chloramine, pesticides, hormones, VOCs, and other organic chemicals.

These two carbon filters not only remove harmful impurities from the water; they also filter out contaminants like chlorine and hydrogen sulfide that affect the taste and smell of water.

RO Membrane

With large particles and potentially damaging chemicals removed in the pre-filtration stage, the semi-permeable membrane focuses on the hardest-to-remove filters. This improves its performance and lengthens its lifespan. 

The membrane filters out over 98% of most impurities, including lead, iron, chromium, fluoride, arsenic, and radium.

It also removes dissolved salts (which is why RO water is mineral-free) and biologicals such as bacteria and viruses.

Alkaline Filter

The next stop for the purified water is the alkaline filter, which has five stages. As water passes through each stage, small amounts of various minerals including calcium and magnesium, are added to the water.

This replaces minerals that were stripped out by the RO membrane.

The water at the other end of the alkaline filter, now full of minerals, has a more natural taste and a higher pH.

Most customers say that they got a pH reading of 8 or more, which is in the alkaline zone.

But depending on the original pH of your water, you might get pH neutral RO water. In some cases, it might still be slightly acidic.

So it’s not a guarantee that you’ll get alkaline water. If you want a machine that reliably puts out alkaline water, get a water ionizer

What the Express Water system guarantees are healthy and tasty mineral-filled water.


The final carbon filter is located just before the faucet. It gives the water a final polish to get rid of any remnant smells and tastes.

Filtering Performance

Express water

The Express Water ROALK10DCG is at par with other top RO water filtration systems.

Its 5-stage filtration process is highly effective at removing virtually all contaminants from drinking water.

Also, it features a better alkaline filter than that of most RO systems.

Most RO filters add only one mineral, usually calcium or magnesium, to the water. The Express Water filter adds five, resulting in tastier and healthier water.

The ROALK10DCG also trumps other pricier systems when it comes to production capacity. In optimal conditions, it can produce up to 100 gallons per day.

The typical production for most RO filters is 75GPD.

If you have a large family or use RO water for more than just drinking, the Express Water ROALK10DCG is ideal.

Water flow rate is also not too bad.

With a flow rate of 0.8 GPM, it takes a little over 6 minutes to fill a 5-gallon bottle. That’s better than most RO filters in this price range.

To increase the flow rate, you can install a booster pump that will increase water pressure (do not exceed the max operating pressure of 80 PSI).


express water undersink water filter

The Express Water ROALK10DCG is one of the more wasteful RO filters in the market.

It has a water efficiency ratio of 3:1, meaning it drains away 3 gallons of water for every gallon of purified water that you draw from the faucet.

You can tap the wastewater and use it for gardening.

Alternatively, install a booster or permeate pump. It will significantly reduce water wastage to 1 or 1.5 gallons for every gallon of pure water.

Installation and Maintenance

reverse osmosis system reviews


Don’t let the 10-stage name scare you. There aren’t ten filters that you need to link together.

The five filtration stages are all within one cartridge that comes already mounted to the filter frame along with the RO membrane.

The system comes 50% pre-assembled, making installation easier and faster.

The installation kit comes with all the parts you need including color-coded tubes, a feed water adapter for ½” and 3/8” outlets, a filter housing wrench and a fast flow faucet.

Because the filter uses push-to-connect fittings, you don’t need any tools to connect the tubes to valves and connectors.

The only tool you need is a power drill to make a hole for the faucet and another for the drain line.

Overall, it takes about 1-2 hours to set up the system under your sink.

It takes up a fair amount of space but should fit most under-sink spaces with space to spare for a few other things. If it doesn’t fit in yours, you can also install it in the basement.


Like most other RO filters, the Express Water ROALK10DCG is easy to maintain. Your work is mostly to monitor it for leaks and replace the filters as necessary.

Our only complaint is the relatively short filter life.

The pre-filters are good for just six months, which is half the lifespan of other RO filters in this price range. The usual lifespan is 12 months.

The RO membrane also has a short than usual lifespan: 1 year compared to the 2-3 year lifespan of typical RO membranes.

In other words, expect to spend a bit more money on maintenance.

What We Like the Most About the Express Water 10-Stage RO System

Express Water RO system

What We Don’t Like

Clean filtered water

The Express Water 10-Stage RO Filter Is Perfect For You If...

Express Water alkaline RO System

You are looking for a high-performance and affordable reverse osmosis system that produces alkaline mineral water.

Our Bottom Line

Express Water ROALK10DCG

The ’10-stage’ term is not just a marketing gimmick. The five stages of remineralization make a difference in the taste and quality of water.

The Express Water ROALK10DCG is nowhere as good as a water ionizer in making alkaline water, but it is far better than most RO systems, even those with an alkaline filter.

If you want to make your drinking water healthier and tastier, we highly recommend the Express Water 10-stage reverse osmosis filtration system.

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