Reverse Osmosis Water Tastes Bad After Changing Filter

Reverse Osmosis Water Tastes Bad After Changing Filter

Reverse Osmosis (RO) systems have become increasingly popular in the last decade or so, both for commercial, residential, and industrial applications. RO filters produce the cleanest water possible as long as the system is well maintained. Maintenance includes sanitizing the system and replacing filters on time. However, sometimes, after changing filters, the RO water can taste bad. Why is that?

Reverse osmosis water can taste bad because newly fitted filters are coated in a protective element, as well as small carbon particles and debris from the manufacturing process. Depending on where the filters were stored, small particles such as dust, plastic, and fumes could have made their way on to them. The grease from fittings also settles on the filters. All of the above can give RO water a bad taste after a filter replacement.

In this article, we are going to learn how to avoid the bad taste in RO water every time we change filters, and discuss other common problems faced by users. Let’s get started.

Read my comprehensive article about reverse osmosis.

Why Does RO Water Taste Bad After Changing Filters?

A new filter is not free from its own share of contaminants. It collects plenty of debris from manufacturing, fumes during storage, and grease at the time of fitting. While these are the top reasons why reverse osmosis water tastes bad after a filter replacement, they aren’t the only ones. A bad taste and smell in the water right after a filter replacement could also be an indication of some other issues.

Preserved water in the system

If the RO system hasn’t been used in a long time, then the water will not only taste bad but will also have an unpleasant smell to it. In that case, the new filter is not to be blamed. The first flow of water that comes out of the reverse osmosis system, after a long time of non-usage, is from the stored water. This stagnant water has been in the system for weeks, months, or years and has been contaminated.

Low-quality filter

Although rare, there is some possibility that your new filter is of inferior quality and doesn’t purify water as well as it should. In that case, the drinking water you receive is full of contaminants and sediments, and therefore tastes bad.

How to Prevent RO Water from Tasting Bad After Filter Replacement

If your water tastes bad every time you replace your RO filters, here are some foolproof solutions that will solve the problem.

Cause Solution
Manufacturing Debris and Grease from Fitting ➔   Turn on the faucet and let the water run for about 15 minutes or until the filter is rinsed
Preserved Water in the System ➔   Most system manufacturers recommend sanitizing the system when changing filters. This would clear any stored water in the system and other sources of contamination.

➔    If your RO system hasn’t been used for more than a month, there could be mold and bacteria growth in it. In that case, turn on the backwash function to reverse the flow of water and clean the system thoroughly.

Low-Quality Filter ➔   Do your research before purchasing filters. Branded filters are better quality than non-branded ones. If possible, purchase from the same manufacturers as that of your RO system.


Generally, make a habit of dumping two to three complete tanks of water after every filter replacement to avoid the bad taste in your drinking water.

Other Types of Common Problems with RO Systems & Their Solutions

Bad taste in the water after filter replacement isn’t the only issue faced by consumers. Here are some other common problems reverse osmosis users struggle with on a daily basis:

Bad taste & nasty odor

If you are noticing the bad taste and nasty odor in your RO treated water, it’s a clear indication that the filters need to be replaced. Even if your last filter replacement was only a few months ago, the amount of water or the quality of water can create a biofilm of contaminants on the filter a lot sooner, rendering the filters useless. What’s more, the layer of organic and inorganic compounds on the filter will make the water even more contaminated.

Poor water flow

Slow water flow from the RO system can be due to low water pressure in your plumbing. An RO system requires a water pressure of 40 to 60 PSI to operate properly and push the water through all the filters. If the problem is recent, there could be a leakage in the pipes.

Loud noises

RO units are fitted with pumps to ensure the right amount of pressure is present in the system. These pumps vibrate at supersonic speed to maintain the water pressure and tend to become loud and noisy over time. These pumps might need a replacement when they become too noisy and are struggling to function.


Q) What happens to the impurities removed from the water in the RO system?

Once the RO membrane separates the impurities, the purified water is pushed through the membrane, into the permeate tube, and towards the faucet. The rejected water flushes downstream, dumping the impurities into the drain and cleaning the membrane in the process.

Q) How often should we change RO filters?

RO filters must be replaced every 12 months. This will make sure that your RO unit stays in optimal condition and lasts a long time. Not replacing filters once a year will result in contaminated water even with the RO unit in place.

Q) Do reverse osmosis systems need electricity?

No. Reverse osmosis systems need water pressure to function. In case of a power outage, your RO system will continue to work and give you access to clean, purified water.

Final Thoughts

Water tastes bad after a filter replacement because the filter itself contains fumes, grease, and debris. By running the water for a few minutes, the impurities present in the filter will be rinsed or flushed out removing any and all contaminants that could give water a bad taste.

Sanitizing the system regularly and investing in high-quality filters will also ensure no bad taste. Taking these steps extends the life of your system and results in clean amazing tasting water.

Boch Richard

Richard Boch is a chemical engineer responsible for designing water filtration systems for industrial and residential customers. He has more than 20 years of experience with ion exchange, activated carbon, and reverse osmosis. Richard's expertise has made him a go-to source for municipalities and businesses looking to improve their water quality. When he's not working, Richard enjoys spending time with his wife and two young children.

Recent Posts