Sanitizing the rain tank

Barb LeeContributor - September 28, 2021

Mr. Dogpatch drew the rain tank down for the first time since installation this last week.  Our guide to installation said to leave the tank alone to allow the biofilter to develop, but we thought it was time.  So he dumped a gallon of bleach in, let it set for a day, then opened the valve.  It got a thorough pressure washing and some of the intake plumbing was taken down and cleaned.  No sooner did he get finished than this fabulous two day rainstorm hit, delivering over 600 gallons of fresh rainwater (so far). 

The tank has saved us a few times when the power went out and we couldn’t pump the deep well (hopefully the new generator will alleviate that problem).  We bring the water into the house in five gallons jugs, treat with a tablespoon of bleach, then run through a sediment filter and a Berkey tabletop filter.  The horses drink it straight! 

We were both very nervous, pouring that resource onto the ground to clean the tank!

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I was looking into the best strategies and how to properly collect rain water and was surprised to learn how beneficial that biofilm is. Even on an asphalt roof, the toxins were absorbed into and stuck to the biofilm on the sides while the water in the center had extremely low levels. 

That being said, I would do what you did and do the occasional bleach wash.

 

Interesting!  Husband did all the research on this project so I didn’t know the particulars. We used to use the filtered rainwater for our tropical fish and it seems the water was beginning to sludge up our Berkey cartridges too quickly.  We now run the water through a sediment filter first, but it still seemed like the tank was due for a good cleaning.  Cheaper than buying new Berkey cartridges! I’m sure the biofilm will reform quickly.

 

That’s just what I heard the author of the book Essential Rainwater Harvesting Rob Avis say in a YouTube video a while ago. I still have to read his book sometime.

What does your sediment filter look like? Good to know that I may have to run it through that before going through the Berkey filter. Those aren’t cheap like you say.

 

Jay, I think we have that book.  He also downloaded reams of information from a university, but that’s all gone and I don’t remember which…he says Virginia.

The sediment filter is just a little Camco RV unit with quick connect hose fittings, nothing fancy.  The tank is plumbed so that the water enters from the bottom, but is drawn off of the top 4″, so there’s typically very little sediment, but I think that the accelerated clogging of the cartridges was a signal that the tank needed service.  We have a small 120V Harbor Freight pump on the tank that does a great job of delivering the water.