What If There’s Mold In My Sawyer Water Filter?


Think about how you handle your water filter. Most of us just toss our filter into storage after getting home and don’t think about it until our next trip. Sawyer filters take weeks to dry so putting them in dark storage can definitely lead to mold growth. What if there’s mold in my sawyer water filter?

You will need to clean your Sawyer Filter if there’s mold in it. Backflush the filter with water and force a bleach solution through the filter media. Give your filter time to sit with the bleach solution and repeat the process.

Honestly, mold growth is almost impossible to prevent completely. After months/years of using your filter you will eventually slip up and need to deep clean your filter. Luckily cleaning your filter is easy so keep reading to find out how.

Getting Mold Out of A Sawyer Water Filter

Anything that’s placed into storage before it’s fully dry will eventually grow mold. There’s really no way to get around that! Your Sawyer water filter can take weeks to dry so it will eventually grow mold. What can I do if there’s mold in my Sawyer Water Filter?

You need to clean out the filter using a water and bleach solution. Use the backflush plunger filled with your bleach solution and force it through the filter. Give the bleach a few minutes to work and flush it out with clean water. I’ll go into a detailed cleaning guide below so keep reading for more info.

How Do I Know If There’s Mold?

You will definitely know if there’s mold in your water filter. Trust Me! It will start to get a funky smell and taste. You’ve definitely had that mold taste at some point. It’s like a weird earthy taste with a musty smell. Once it gets really bad you’ll notice mold growing around the mouthpiece and end piece.

So my Sawyer Mini Filter tastes nasty and definitely has mold. What can I do about that?

Cleaning and Backwashing Your Sawyer Water Filter

Cleaning out your Sawyer filter is really easy. All you need is water and a little bit of bleach to sanitize the filter and kill internal mold. Your filter should have came with a backflush plunger to force water through it. I prefer the cleaning coupling that screws onto my water bottle to force water through.

You should be backwashing with clean water after every use. There’s really no excuse not to backwash since it’s so easy.
Follow the same process with a bleach solution if you start to notice mold. I deep clean my filter with bleach at the beginning of every season and after long periods of inactivity. It only takes like 2 extra minutes so I run bleach through mine every 2-3 months.

  1. Backflush With Filtered Water: Start off by backflushing the filter with distilled water. Fill up your Sawyer cleaning plunger with clean water and force it in the opposite direction(against the flow arrow). Close the plunger and force the clean water through the filtered fibers. Repeat the process several times until the water comes out clean and easily. The key to a successful backwashing is to be forceful. A good backwash should be able to restore over 98% of the filters original flow rate.
  2. Make A Bleach Solution: You need to make a bleach solution if you notice mold growth in your filter. I usually fill a coffee cup 2/3 full with water and add a splash of bleach. All you need is like a tablespoon of bleach. Mix the solution together.
  3. Backflush With Bleach: Follow the backflush step above using the bleach solution. I usually run the bleach through the filter and right back in my coffee mug. Keep running it through 3-4 times and give the filter a few minutes to soak up the bleach.
  4. Backflush Again With Water (wait 10-15 minutes): After waiting about 10-15 minutes you’ll want to repeat the backwash process. You want to pay special attention to the water color and pressure. You’re good to go once the waters clear and it’s easy to suck fluids through. Make sure you’ve ran a bunch of water through the filter before trying to drink out of it.
  5. Repeat If Needed: Keep repeating the process and you should eventually have a clean filter. Watch the instructional video below for more information.
  6. Soak It In Filter Water: If a standard backwash doesn’t get your filter flowing again, I recommend soaking your filter in hot water. Don’t let the water get too hot (140 Degrees Fahrenheit). Keep it on the stove and let it sit for 2 hours. If that doesn’t work, soak the filter in vinegar for 30 minutes and afterwards force clean water through it. This should break up all the grown in dirt/mold so you can repeat the cleaning process.

It May Be Time To Buy a New Filter

The Sawyer Mini and Squeeze filters are easily one of the most popular backpacking water filters on the market. You really can’t beat them for the price. I recommend thinking about the price of your filter before going through a deep cleaning process.

There’s a point where you should probably just replace the filter once it gets really nasty. I once cut open a Sawyer Mini that I had been using for a few years that had started to smell. It was extremely gross inside and completely covered in black mold. I would have replaced that thing a year earlier had I known how nasty it was.

At like $20 I tend to treat my Sawyer filters like a disposable item. It might be rated to 100,000 gallons of water, but it’s time to replace your filter after 1-2 years of use. Regularly backwashing the filter with clean water and giving it time to dry will extend the filter life.

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