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This week, we had an unusual thing happen at our house – we discovered mold in our water filter! It was gross and disgusting, and I had to find a way to get rid of it.

Let’s start at the beginning.

A year or so ago, I got a Berkey Light water filter. My daughter had one, and I’d read great things about them, so it was one of the first things from eFoods Direct that I got. I was so excited when it arrived, and soon we had the top container full of water and filtered drinking water. I love having clean, filtered water in my kitchen, and actually, I consider it a small part of being prepared. At any moment, if my water supply were to be cut off, I would still have a few gallons of clean water in my water filter, as well as a way to filter more water as needed.

A few days ago, my son came in and said, “there’s yellowy-green stuff in the water filter.” What? Eww! Gross! Of course, I went right in and looked, and, sure enough, there was mold growing inside the bottom container, in with the filtered water.  It hadn’t even occurred to me that it was possible.

I started doing some research on the Berkey water filter site to see if this is an anomaly or something to be aware of, and decided I should pass along what I found out.

From the Berkey site, I learned that mold inside a Berkey Unit (or on the Purifier elements) is usually caused by the unit being placed in a heated environment, such as near a window where there is sunlight, or near a clothes dryer that is run frequently. The heated dark damp environment can encourage the growth of mold. They recommend moving the Berkey to a place away from a heat source. (Also, they specify that while mold can grow on the outside of the Purifier elements, it cannot grow inside the elements. It should be cleaned off the Purifier elements with a ScotchBrite pad, and use white vinegar or soap and hot wipe down the unit chambers.)

My filter sits on a table in my kitchen, near a window. The blinds on the window stay closed most of the time, but it didn’t occur to me that the water was still heating up a bit. I’d never noticed the water being warm – but then, in the summer I prefer ice in my water anyway.

So here’s what I did: I emptied as much of the water as I could through the spigot. I watered my houseplants with that water. Then I took the top section off (the section that holds the filters). Fortunately, the top section was already almost empty. It pulls off easily, though it did drip a bit from the wet filters, of course. That left me with the open bottom section. I lifted it up and carried it around to water more plants. I washed out the bottom section thoroughly with soap and water. Then I decided to swish around some bleach and water solution to be sure the mold was killed and gone. After I reassembled my Berkey, it started filtering again, and I felt much better about drinking the water.

How can I avoid mold in my Berkey in the future? The Berkey website suggests “wash lower chamber once per month with soapy dishwater.” That is definitely worth doing – I just need to remember to do it at a time when the water level is down low already.

The bottom line is, the problem of mold in my Berkey Light water filter was easily solved by thoroughly cleaning out the filter and reassembling it. The Berkey website was helpful in providing answers, and didn’t take nearly as long to remedy as I worried it would.

I also learned about how to keep my filters working well and how to know when it’s time to replace them. I will talk about those issues in an upcoming post.

For more information on Berkey water filters, check the Berkey Filtration site at, and enjoy your Berkey!


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