Potable rainwater harvesting in climate zone 5a
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We are looking to design a rainwater harvesting system to provide potable water for a cabin in zone 5a. We are not finding professionals with much experience in this area. Any recommendations for where to turn for advice?
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Hi Daniel,
You might want to reach out to Brad Lancaster. He's had several books published, as well as posting several helpful videos on the topic.
https://www.harvestingrainwater.com/offerings/
Have you started shopping for cisterns/tanks yet? There are any number of suppliers online: https://www.tank-depot.com/p-130/underground-water-storage-cistern-tanks
You could also reach out to this builder/homeowner who has an above ground tank in his yard here in Illinois:
https://www.greenbuilthometour.org/project/net-zero-passive-country-house-5644-s-iowa-dr-pembroke-township-il-60694/
Neil can be reached at: https://snpeck.com/about
If you get your system installed and up and running, please report back here with some of the details. I know that I'd find it interesting, so I assume others on GBA would as well.
Thanks Eric, for these resources! I am following up with them.
Daniel
Daniel,
For quick idea of what's available and required, you may find this useful. I have used them on several jobs: https://www.vanislewater.com/we-are-rainwater-harvesting-experts
Thank you, Malcolm. Looks like a great supplier.
I'd done a fair amount of research into this subject.
There are three key things to consider:
1) Scaling - you have to understand collection vs consumption; I had created a spreadsheet to manage draw-down and re-fill rates, but not sure where I put it (I'd put it together for an off-grid build I was intending; I later used it as a backup plan in case the well where I'm currently at wasn't salvagable- it was, which also gives me knowledge in managing wells!); not sure where 5a is, but what is key is frequency of rainfall as well as amounts- this is why calculating draw-down and recharge is necessary, as this determines the sizing of your tank(s): I did calcs for a location that averaged 21" of precip a year, a fair amount of snow (which is a bit harder to collect water from!), as well as 100"+ where I'm at now (dry during brief summer months, totally wet otherwise). NOTE: consider tank maintenance; if possible having a second tank to switch to for maintenance of the first (or if it manages to fail) is a nice feature to have.
2) Collection surfaces - although most anything can be filtered/treated for it's best to obtain the best water that you can to start with; I'd spec'd my habitats to heat with firewood which meant that I had to consider particulates from the stove being in my water mix (also considered setting up a standalone water collection surface).
3) Water treatment - NO water is pure! Water from the sky can either bring down crap from the air that could be shed off of various things (airplanes, birds etc.) or stuff that's just plain blown onto the surface; I'd always recommend having bacteriological treatment in addition to standard sediment treatment. Rainwater can be quite variable; only thing more difficult IMO would be river water (or wells near a river).
There is, of course, all the delivery aspects, but those are fairly easy in the bigger picture.
You bring up some good points. Thank you!