How to Clean Water Filters

Our step-by-step guide on how to clean water filters and make maintenance easy.

As with any other product, not maintaining your water filter will cause it to deteriorate. Irregular maintenance affects the quality and purity of your water. If your filters aren’t clean, they won’t freshen your water, and so become redundant.

We’re here to explain all you need to know; like when, how often, and how to clean your water filter.

How Do Water Filters Work?

There are many types of water purifiers, from industrial-scale reverse osmosis machines to residential pitchers. No matter the kind, size, build or function, all water filters serve the same purpose. They remove impurities from your supply so that it’s healthier to drink and use.

Most water filters work by pushing water through a mesh, one that only water molecules can fit through. Other molecules, be they contaminants or even minerals like salt, can’t breach this barrier.

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The amount — and kind —of maintenance required depends on what kind of filter you use. Some, like UV purifiers and distillers, don’t use filters, so maintenance is limited to servicing the entire unit when necessary.

With smaller purifiers, especially carbon filters, collected pollution has nowhere to go, and with time, the residue will build up on the filter itself (1). In this case, the filter will absorb some of the contaminants it’s meant to get rid of. The quality and efficiency of the filter will begin to deteriorate until it stops working altogether.

Other purifiers, like certain reverse osmosis machines, automatically dispose of the waste that’s left behind. Even so, these will still need sanitizing to clear away build-up on the interior.

It may be slightly problematic if you have a whole-house water filtration system installed. These units are larger and more complex, so professional installation and maintenance is recommended.

Why Should You Clean Your Water Filters?

Just like your toothbrush needs replacing after a few months to maintain its effectiveness and prevent bacteria from building up, so does a water filter. Since their job is to keep your water fresh and free of contaminants, the cleaner they are, the better they work.

The following are some examples of what happens if you don’t maintain your water filters regularly:

1. Microbes Make Their Way Into Your Water

A popular reason to filter is to remove pathogens from your water. Water is treated by your municipality before it reaches your household, but many people feel that this extra step is necessary.

By neglecting your water filter, you are increasing the risk of these pathogens making their way into your supply (2).

2. Harder Water

The difference between hard and soft water is in mineral content. Hard water has higher levels of calcium and magnesium, while soft water has higher levels of sodium.

Hard water is healthier to drink, but it is harmful to your home, appliances, and even skin. Soft water is preferred in households because it’s gentler on your body, clothes, and plumbing.

If you use a water filter to soften your water, it will lose its effect if you don’t maintain it. Calcium and magnesium will build up on your filter, rendering it useless.

3. Toxins Break Through

Not all filters are effective against harmful toxins, so it’s important to choose the right one. Aim for filters that prevent heavy metals and other poisons — like lead, mercury, fluoride, and chlorine — from entering your drinking water.

These chemicals can have a massive negative impact on your health. The heavy metals we listed are all considered neurotoxins, while chlorine has been linked to many illnesses (3).

Every time you use your filter, you wear it out. With time, it will become ineffective at isolating these harmful molecules, and they’ll contaminate your supply.

4. Toxins Remain

On a less grim note, not changing your filters might affect the taste of your water. Hard water is said to have a more earthy or metallic taste, while soft water has a hint of salt to it. Likewise, chlorine can alter both the taste and odor of your drinking water (4).

Using a filter to optimize the taste of your drinking supply is a valid reason on its own, let alone factoring in the other reasons above. Over time, minerals and toxins will eventually break through your filter and affect your drinking experience.

How to Clean a Water Filter

Now that you know when and why you should clean your water filters, it’s time to get your hands dirty. These methods use little effort and are cost-effective solutions to maintaining your filtration systems. Since carbon filters and reverse osmosis systems are the most prominent, we’ll focus on them.

Reverse Osmosis Filters

Reverse osmosis systems work on two levels. The first is the reverse osmosis membrane filter, which is where most of the system’s efficiency lies. The second is in the pre-filters, which are most commonly made with or incorporate activated carbon.

Before you get to cleaning these out, wash your hands or wear clean rubber or medical gloves. Remember to cut the water supply to the filtration system before you service it.

  1. Drain: First, the water needs draining from the filtration system and tank. Close the faucet attached to the system, too.
  2. Detach: Remove both the pre-filter and reverse osmosis membrane from the system. You might need a wrench to open its casing.
  3. Clean: Use chemical cleaners to sanitize your system. Your manufacturer should have a recommendation of which one to use. If you don’t know which to get, you can use two or three tablespoons of unscented bleach instead.
  4. Remove build-up: You can do this by adding your cleaning solution directly to your pre-filter housing. You then fully open the bypass faucet and let the water run freely to rinse.
  5. Wash the membrane: Wash or wipe your membrane with the solution, too. If you prefer, you can use dishwashing liquid for this instead. Take care to rinse it off well to remove traces of the chemical product.
  6. Reassemble: Once everything has been cleaned and rinsed, you can reassemble and restart your system.

It’s recommended that you flush your system and clean or replace the membrane at least once every year.

Activated Carbon/Charcoal Filters

Cleaning carbon filters isn’t too different from cleaning reverse osmosis ones, but you do need to be more careful with them. You’ll be working with chemicals, so only do this in a well-ventilated area.

Wear gloves, and follow the instructions of the chemicals exactly. It’s best to cover your skin and wear goggles or a mask.

  1. Prep: Fill one bucket with half a gallon of clean water at room temperature.
  2. Add muriatic acid: Slowly add two cups of muriatic acid, taking care to stir it consistently and continuously. Use a plastic stirrer for this.
  3. Rinse the filter: If your filter has obvious build-up or debris on it, rinse it off with a hose. Once it’s clear, place it inside the solution and let it sink.
  4. Wait: The filter will have to stay in this solution for at least five days to remove all contaminants. Ensure the solution remains at room temperature during this period.
  5. Resoak: Once you’ve returned to your filter, let it soak in clean water for five minutes.
  6. Rinse and reinstall: Rinse the filter off with a hose. Once it’s cleaned, reinstall it.

If you’re not feeling up to the wait, you can simply rinse your carbon filters instead. However, this won’t remove toxins or build-up from them completely.


It’s important to slowly add the acid to the water in this order. If you add drops of water to your acid first, it could cause toxic fumes or even explosions. Be careful.

Frequently Asked Questions

How Often Should I Clean My Water Filter?

The manufacturer-recommended replacement time varies quite considerably, with many suggesting every six months. But, this depends on the volume of water going through your filter, as well as other factors.

If your water is hard or sediment-heavy, or if you use a lot of water in your home, consider cleaning them every month. Some experts recommend routinely changing your filters every two weeks, but this is aimed at industrial water usage.

If at any point you taste, see or smell a difference in your water, it’s a clear sign that your filters need maintenance. If all else fails, follow the specific maintenance instructions.

Is Cleaning Better Than Replacing?

It’s inevitable that you will have to replace your filter eventually, especially if it’s an activated carbon filter, which has a limited lifespan.

Cleaning isn’t better than replacing your filters, but can extend their run. Regular maintenance will preserve their quality and efficiency. You could save money on fewer replacements if you take good care of the filter you have.

How Can I Dispose of Old Water Filters?

If cleaning your filters has run its course and you have to replace the entire thing, environmental impact may be a concern. Some manufacturers have a system by which you can return used filters to them for recycling (5).

If that’s not the case, you will have to dispose of your filters as you would any other household waste.

Happy Hydrating

It’s important to clean your water filters so that they can properly clean your drinking water. Though cleaning carbon filters is slightly complex, it’s worth it if you want to save money on replacements while resetting your filter’s efficiency.

With both carbon filters and reverse osmosis membranes, don’t forget to clean your filtration unit, too. Wipe it down or rinse it’s components, so it looks clean and fresh.

Let us know how you managed cleaning your water filter. Drop us a comment in the section below, and good luck!

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About the Author

Peter Gray

Peter has been a homeowner for 35+ years and has always done his own repair and improvement tasks. As a retired plumber, Peter now spends his time teaching others how they can fix leaks, replace faucets, and make home improvements on a budget.