Letter Re: Seeking Advice on Rainwater Catchment and Filtration

Mr. Rawles:
When constructing a rain-catch such as this one, which the good folks at Lowe’s [–a major hardware store chain in the US–] suggest for economically watering your garden, is there any instance where it would be okay to use this as a backup for drinking water?

Obviously, one would be foolish to drink directly from containers that are not food-grade or if the water has been sitting for too long a time. But, my question is does that change if you plan on running the water through a purifying process such as through a Berky or this economically priced alternative.

It looks like these filters might not last as long as the Berky filters, but are quite a bit cheaper and have a higher flow rate (this is what I was told – YMMV). A representative of the manufacturer claims to train the “second largest disaster relief organization in the world” who “use this filter exclusively” and that it is used by missionaries in 38 countries around the globe. I was also told that it was nominated for a World Health Humanitarian Award for 2008. Also, it supposedly outperformed the Berky in a trial run by Johns Hopkins University, but I have been unable to verify that claim. I can verify that Johns Hopkins University did give it a passing grade; as did the National Sanitation Foundation (NSF) under Standards 42 and 53, AEL Laboratories, Analytical Food Laboratories, British 5750 Quality Standard, and England’s Water Research Council standard.

So, my two questions are:

1.) Is it safe to drink rainwater caught in a non food-grade vessel, provided you filter it through a sub-micron apparatus first?

2.) What are your thoughts on the aforementioned filter? Thanks, – J.S.C.

JWR Replies: In answer to your questions: Rainwater catchment for domestic water is very popular in Hawaii. There, most families do little more than use a sediment filter and bulk chlorination. You should of course never re-use something like a fuel tank or a toxic chemical tank for a water barrel. As I explained previously in SurvivalBlog, the issue with “non-food grade” HDPE plastic buckets and barrels is that some of them are manufactured using toxic injection molding release compounds. Whether or not a ceramic water filter would remove any such trace chemicals goes beyond my expertise. Perhaps a chemist or a water quality specialist amongst the SurvivalBlog readership could enlighten us.

We have a Big Berky here at the ranch, and love it. The two-bucket ceramic filter that you mentioned is remarkably similar to the improvised Berky clone that I detailed in a SurvivalBlog post back in May. Both their design and mine have similar cost, similar do-it-yourself labor requirements, and they will process a comparable volume of water. This isn’t like comparing “apples to oranges”. It is more like comparing Bartlett Pears to D’Anjou Pears.