Brita, PUR & Co. – How to Clean a Water Filter and Reuse It

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In theory, cleaning and reusing your old water filter is a better alternative to replacing it with a new cartridge every month or so. The latter is not only more expensive, it’s also a burden on the environment.

However, if you want to be able to fully enjoy the benefits of home water filtration – and that is pure water – cleaning a used filter isn’t always that simple and effective. What you can and what you shouldn’t do you are going to learn in this post.

Key Takeaways

Cleaning sediment filters:

  1. Rinse off/scrub
  2. Optional: Soak in muriatic/oxalic acid solution for 15-20 minutes and rinse again

Cleaning carbon (charcoal) filters:

  1. Cut netting close to top/bottom and remove
  2. Cut through paper layer underneath but leave a small strip attached
  3. Peel back outside paper layer
  4. Rinse off all rough dirt from paper and charcoal core
  5. Scrub paper layer using a brush and bleach solution
  6. Rinse thoroughly
  7. Roll up paper layer tightly and secure with nylon ties

How to Clean a Water Filter

First of all, if and how you can clean your water filter depends on what type you are using. While some such as synthetic fiber-pleated sediment filters can be cleaned well to restore filtration speed and effectiveness, others like most paper models are less suited for this.

Also, you should consider if the whole cleaning process is really worth your time, opposed to simply making annual or biannual replacements that are going to cost you $40 in total.

What’s more, through cleaning you won’t be able to remove all the trapped contaminants so replacing your old filter with a new one will eventually need to happen. And although bleach does a great job at disinfection, there is no guarantee that bacteria, mold, mildew or any other harmful germs will not accumulate inside your filter without you noticing.

In other words: Especially if you are going to use the water for drinking you want to make sure that the filtration is up to standards and can compete with a brand-new cartridge.

Cleaning Sponge with Foam Heart

Sediment Filters

If you are on a private well with high iron content or excess hardness, or your city supply contains high amounts of impurities, cleaning your sediment (pre-)filter on a regular basis is a great way to extend its lifespan. Here’s what you need to do (does not work for all filter types):

  1. First, you will require some type of acid. Muriatic acid and oxalic acid work great for this. If you prefer oxalic acid, mix about 2 oz of oxalic acid powder (available on Amazon) with 1 gallon of plain water. Muriatic acid can be bought as a pre-mixed solution.
  2. Remove the filter housing and take out the cartridge.
  3. Put the O-ring aside.
  4. Rinse the housing to get all heavy particles out.
  5. Thoroughly rinse off the filter. The more you get off through mechanical cleaning now, the more effective your acid mixture is going to be.
  6. Soak the housing with the cartridge inside of it in the acid solution for 15 to 20 minutes (depending on the level of contamination). No scrubbing whatsoever is required here.
  7. Thoroughly rinse both components with plain water. You want to make sure that there remain no acid leftovers.
  8. Put everything back together.

On a side note: You can neutralize the acid with regular baking soda – a couple of tablespoons should be enough – so that you don’t have to worry about pouring it down your drain.

Carbon (Charcoal) Cartridges

Most carbon block filters consist of 3 layers. In their inside there is the solid carbon block obviously. Wrapped around it is a paper-type layer. The paper removes impurities from your water that the carbon could not trap. At its outside, a carbon filter usually has a plastic mesh netting that holds the paper in place. To clean the filter, you will need to remove that netting:

  1. You can use a knife to cut twice around the entire perimeter as close to the top/bottom of the cartridge as possible. Remove the netting.
  2. Then cut through the paper layer underneath but leave a small strip, maybe a half inch, attached to the inner carbon block. This way the paper stays on and is easy to roll back up.
  3. Peel back the outside paper layer.
  4. Use your garden hose to rinse off all the rough dirt from the paper as well as the charcoal core.
  5. Use warm water with one or two spoonful of bleach to scrub off the paper layer with a brush from both sides.
  6. Optional: Clean the filter housing if need be.
  7. Thoroughly rinse everything with clear water.
  8. Roll up the paper layer really tight.
  9. Secure it with a nylon tie at the very top. Trim off the excess end. Add 3 to 4 more nylon ties this way.
  10. Now it’s time to put everything back together.

Following this procedure, you will notice a huge improvement in water taste and pressure. And what’s great is that you can do this several times before replacement is required.

In case your carbon filter does not have a paper layer that you can peel off, use a scrub pad or iron sponge to brush off its outside. This will help to improve water flow and aesthetics a great deal.

Reactivating Activated Carbon

In a forum we read that you could boil an activated carbon block in water for about 15 minutes in order to recharge it. The longer the boiling, the more contaminants will presumably be released.

Not having tried this ourselves, we cannot say if it really works or not.


Brita filter pitchers and dispensers are easy to use and give you access to somewhat cleaner drinking water. And although you save quite a lot of money compared to buying bottled water, costs for replacement cartridges can start to add up quickly.

However, for less than a dollar you can refill your Brita cartridge with fresh granular activated carbon so you won’t have to buy a new one each month.

Granular Activated Carbon

Activated carbon (or charcoal) is the main filtration component that Brita filters use. It traps chemical impurities such as chlorine in its pores. But as more and more pores become occupied as time goes by, the filtration becomes less effective until at some point it finally stops.

This is when we have to replace it. By the way, activated carbon is available at your local Walmart for instance and can be bought in bulk at a low price. You can also order online. Either way, you will save a ton of money in the long run.

How does the actual replacement work?

  1. Drill or cut a hole in the middle of the cartridge head. About ½” should do.
  2. Optional: Consider adding a couple of air vents to the top of the casing to increase water flow a.k.a. filtration speed. You can use a sharp knife for this, but be careful not to cut yourself!
  3. Pour the old charcoal out of the hole.
  4. Thoroughly rinse the empty housing with clear water to flush out any remaining filter media.
  5. You might also want to sanitize the housing with household bleach at this point. If you do, rinse thoroughly afterwards.
  6. Fill in the new carbon. Using a funnel makes this a lot easier. The more carbon you add, the longer the cartridge will last.
  7. Carefully knock the filter on your counter so the media can settle inside the cartridge.
  8. Use a cork or rubber piece to seal the hole.
  9. Install the cartridge in your pitcher/dispenser.
  10. Flush the carbon media.

Thanks to this simple modification you can now use your cartridge time and time again which is much more environmentally friendly than throwing another one into the trash every single month.

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Modular Filters (e.g. Refrigerator)

For modular filters that your refrigerator uses all you can do is flush with plain water from both sides. Meanwhile, use a screwdriver to tap on the filter to loosen any larger debris.

Some experts also recommend soaking modular filters in warm water with a gentle cleanser – think vinegar or dish soap. Let the filter soak between 10 and 30 minutes. Thoroughly rinse afterwards until the water comes out all clear. Finally, let the filter air-dry before popping it back inside your refrigerator.

How to Unclog a PUR Water Filter

It’s no secret that PUR’s pitcher filters are prone to clogging. After just a couple of days use, you might see a drop in flow rate that makes the whole filtration process painfully slow.

There are two possible explanations for this:

  • According to PUR, bubbles or air pockets have become trapped inside the filter. You can test this by putting it in a bowl full of water and see if it floats.
  • Small Styrofoam balls that are mixed into the activated carbon media have obstructed the holes of the pleated filtering element at the bottom where water is supposed to flow out.

The solution for 1.) is to shake the cartridge for 5 to 6 seconds holding it upside down at a slight angle. Can you hear the carbon moving inside? If that doesn’t help, tap it against a hard surface a couple of times. Put the cartridge back in the water to see if it still floats. If it sinks, pop it back into your pitcher or dispenser. The flow rate should be way better now. If the cartridge continues to float, repeat the shaking and tapping.

If you struggle with Styrofoam balls plugging the holes of the pleated element, force water through each of the small slots at the bottom of the filter. You can use a faucet sprayer for this. This should dislodge whatever is stuck in there.

Clean Only If It Makes Sense

All in all, you should only clean your used water filter if it makes sense, meaning that you can save money doing so, it’s not too much of a time commitment, it’s more ecological than simple replacement and filtration performance will not be compromised – the latter is key!

If that is the case, you now know how to clean a water filter the right way. Happy cleaning.

If you have any questions about how to clean water filters please don’t hesitate to leave a comment below!

About the Author Gene Fitzgerald

Gene Fitzgerald is one of the founders of BOS and currently head of content creation. She has 8+ years of experience as a water treatment specialist under her belt making her our senior scientist. Outside of BOS, Gene loves reading books on philosophy & social issues, making music, and hiking.
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