How To Change A Reverse Osmosis Filter in Easy Steps?

reverse osmosis filter change

Changing the filter and the filters of your reverse osmosis system regularly is vital if you would like excellent tasting drinking water that’s clean and healthy.

And the good news is that the medium Joe may achieve it with no plumbing experience. All you want are a few necessary supplies and a little bit of patience.

How to Change Reverse Osmosis Filters

So, how can you change the filters of your RO system?

Although every model is somewhat different, here are a few necessary actions that apply to most RO units:

  1. Begin by washing your hands — you do not want to contaminate your new filters.
  2. Turn off the water supply.
  3. Close the storage tank valve.
  4. Open the RO tap to depressurize the system and drain any remaining water. When the dripping ends, close the tap.
  5. Put a bowl under the system.
  6. Remove this pre-filter(s) housing, which you need to replace by turning clockwise. You might require a filter wrench or strap wrench for this. Additionally, it makes sense to have a towel at the ready in case of spilling water. A bucket is useful to place the previous filters in.
  7. Wash the home’s interior (s) with warm water if need be. If you would like to disinfect your system, use odourless household bleach or another good sanitizer. Rinse thoroughly afterwards.
  8. Install the new pre-filter(s). To prevent leaks, be sure that all black rubber O-rings are in position and stable shape before rewinding the housing(s)– substitute lubricate by silicone grease if requirement be. Don’t hesitate to use a wrench to tighten the housings, but take care not to overtighten!
  9. To change the post-filter, push and hold down the collet from the quick connect fitting to pull the tubing. Repeat on the other end. Remove the cartridge and put in replacement (check arrow for flow management). Reconnect the filter by merely pushing the tubing to the fitting on each side. Pull back on the tube to ensure a safe connection.
  10. Turn on the water supply again.
  11. Take out the RO tank valve.
  12. Start the filtered water dispenser and allow the system to flush for a few minutes.
  13. Check for leaks.
  14. Close the drain and allow the tank to fill.
  15. If you have changed the post-filter, you need to discard 1 or 2 full water tanks. Discoloured water may come from the faucet in the beginning. That is nothing to worry about. Only the carbon fines are being flushed out and ought to clear out after the first or second flush.

Finally, write down the date of this filter replacement as advice for the next. Moreover, if your RO faucet includes a filter change indicator, remember to charge the battery.


Replacing Modular System Filters

Replacing modular filters is far more convenient. There’s no need to switch off the feed water to release pressure. Just place a bowl beneath the machine, twist off the old filters, and install the new. Do not forget to check for leaks! That’s all.

Frequency: How Frequently to Change

We get it, you don’t wish to replace filters too frequently and waste money, but you also don’t want to leave them for too long, putting your health at risk.

What’s most essential is that you change regularly. It is the only way to ensure consistent water quality. How frequently primarily depends on two factors:


The state of your feed water — elevated levels of sediment or hardness minerals, as an instance, will reduce pre-filter lifespans significantly.

Just how much water you have — the more water you use for cooking and drinking, the earlier the filters will reach their capacity limitation.


That being said, regular carbon and sediment pre-filters should last between 6 and 12 months. A carbon post-filter is generally excellent for 12 months, though some can last up to 2 decades.

Please consider these as general guidelines. Especially inexpensive aftermarket filters may require more frequent replacements.

By the way, if you’re going to purchase from another source to make sure the quality is up to standards — believe NSF certificates.

Change Reverse Osmosis Filters

Failing to Change Filters In A Timely Fashion Will

  • Reduce the overall purity of the permeate water.
  • Favour the accumulation and expansion of waterborne pathogens (fouling) from the filtration system, which could influence your health and add an offensive taste and odour to your water.
  • Result in a drop in output water flow and pressure.
  • Cause increased wastewater generation, which finally contributes to a higher water bill.

All four are indicators a filter replacement is probably overdue.


Sediment Pre-Filters

Sediment Pre-filters are located in stage 1, occasionally stage 1 + 2, of just about all RO under sink filter units on the market. They trap dirt, rust, silt, and other debris to protect the delicate reverse osmosis system at the system’s centre from premature greying.

Carbon Pre-Filters

Carbon Pre-filters are located in stage 2 (and 3). The capsules contain triggered or catalytic carbon in granular or block form. The filters effectively eliminate chemicals, including chlorine and its disinfection byproducts and VOCs, which would otherwise destroy the RO membrane. They’re also great for getting rid of tastes and odours.

Carbon Post-Filter

Carbon post-filters become involved in filter stage 4 or 5 and give your water a finishing touch. They are primarily used to eliminate residual tastes and odours, which may have leached into the water while at the storage tank.

RO Membrane Replacement

Lead, Fluoride, bacteria — a reverse osmosis system that’s in good shape removes up to 99 per cent of water contaminants.

The way to keep a membrane in great shape? First of all, through routine cleaning and appropriate pre-treatment of the feed water.

However, despite the most thorough cleaning process and the ideal pre-treatment setup, every RO membrane needs to be replaced eventually…

How To Replace

Before you start, you need to inspect the product manual. It probably includes detailed instructions describing how to alter the membrane on your particular system.

  1. Again, begin by washing your hands.
  2. Turn off the water supply.
  3. Close the storage tank valve.
  4. Open the RO tap to depressurize the system and drain any remaining water. When the dripping stops, close the faucet.
  5. Take out the water line from the membrane covering the cap. Push in and hold down the co toilet against the quick connect fitting to pull the tubing. You may also have to remove a plastic clip.
  6. Remove the cap by turning clockwise. You might require a filter wrench or strap wrench for this. Additionally, it makes sense to have a towel at the ready in case of spilling water.
  7. Take out the old membrane. If it does not move, use needle-nose pliers.
  8. Clean the interior of the membrane covering with warm water if requirement be. Odourless household bleach or other pleasant sanitiser are used for disinfection. Rinse thoroughly afterwards.
  9. Push the new membrane into the home in until it is sealed tight. The end with the two black O-rings goes in first. Hint: Try to avoid touching the membrane with your bare hands to stop contamination.

       10.Double-check the  black rubber O-ring remains tight and is in good                shape before screwing the home cap back — replace or grease with              silicone grease if required be. Don’t hesitate to use a wrench to                      tighten the cap, but take care not to overtighten!

  1. Rejoin the membrane by driving the tube into the cap fitting. Drag back on the line to ensure a safe connection.
  2. Turn on the water supply again.
  3. Take out the RO tank valve.
  4. Start the filtered water dispenser and allow the system to flush for a few minutes.
  5. Check for leaks.
  6. Close the tap and allow the tank to fill.
  7. Discard one or two full tanks of water. This is to flush out the preservative within the membrane. If the water has a humorous taste/smell to it after two rounds, then keep flushing.

As with the filter replacement, it’s helpful to write down today’s date as advice for changing the membrane next. 


RO Membrane Replacement

When To Replace

The safest and easiest method to determine if your membrane needs changing is by measuring water TDS (Total Dissolved Solids). This can be achieved with a TDS meter.

First, check the TDS of the untreated tap water. After that, test the purified RO water.

You can determine the TDS rejection rate by using the following formula:

Rejection Rate in percent = (untreated tap water TDS — purified RO water TDS) / untreated tap water TDS x to00

If the rejection rate drops below 80%, it is time for a replacement.

Another index for a worn-out membrane is decreased water flow from the faucet.


How Long Does An RO Filter Last?

According to the program, state-of-the-art reverse osmosis membranes typically last for 3 to 5 years, so long as you replace pre-filters. If you’re on well water and the contamination is terrible, the new membrane may be required each year or another year.

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