underground cistern setup + solar pump

Hey folks,

I am setting up an underground cistern in Wisconsin zone 4 and have some questions for those who have previously set up a similar system in a cold weather climate. After reading through the literature and pricing out options, I'm leaning toward h a 1700 gal poly Infiltrator tank which is reinforced with fiberglass. Less leaks than concrete, longer lasting, can be re-used if it ever fails as a chicken coop or other shelter, easy installation. I plant to have this cistern gravity feed to the house, although I'll only get about 15 psi max. Not the end of the world, we can install a pump if needed. I plan to have a slow solar well pump installed, which is going to be expensive- for both the deep well drilling and the solar pump, but I am also planning that this tank can be filled with rainwater from a nearby building or water trucked in.

My questions are general- who has experience with an underground cistern in a cold climate? I don't know anyone who does out of all the permaculture or regenerative homesteads I know of. I've done internet research, have read Essential Rainwater Harvesting and there are some nice details in there, but I'm kind of lost as to how to setup the specific ins and outs of the tank, shutoff valves, lay piping, etc. Does anyone have any links or suggestions on who do I talk to? What kind of expert is this? Did you add insulation on top of the tank, etc? Thanks y'all!

-Courtney

Talk to the sellers of the tanks and try to connect with their customers. Lotsa work, but maybe find interesting people and _maybe_ find actual installations.  Find out if there is permitting involved with tank installs and if so, start scouring county permit records. More work.


Regards,
Rufus

Things that will help
Always being full, with equal pressure inside and outside (water&earth)
Being Spherical to evenly displace forces
Being below the frost line so the water doesn't freeze.
Possible insulating the top and sides.
Put the tank in your basement.

You can connect 3 of these for about the same cost and storage capacity
https://www.plastic-mart.com/product/1533/550-gallon-underground-water-cistern-storage-tank-40856

S Bengi wrote:Things that will help
Always being full, with equal pressure inside and outside (water&earth)
Being Spherical to evenly displace forces
Being below the frost line so the water doesn't freeze.
Possible insulating the top and sides.
Put the tank in your basement.

You can connect 3 of these for about the same cost and storage capacity
https://www.plastic-mart.com/product/1533/550-gallon-underground-water-cistern-storage-tank-40856

Hey S Benji, thank you for your input! Those look pretty near but my concern would be having so many connections which would be weak links. Also we don’t want to use a pump so we might make an uphill underground room into the hillside, or bury it uphill. Round/even pressure seems to be right if buried, but of course we can’t guarantee they will always be full as we will have a slow fill solar pump. The one I was looking at is shaped like almost like a cylinder on its side, sort of like a long john. No seams on top. I see the disadvantage pressure wise of an upright cylinder.

I dont really have any advice just experience. Growing up dad had a 8 foot deep pit dug and a normal vertically round tank 1250 gal I think was placed in this pit. We put a plywood roof over top of it. Eventually the sides caved in and left only the top exposed. At first we had it hooked up conventionally to the outlet on the bottom but eventually went with a submersible pump that sat right inside the tank. The submersible pumps are a lot more expensive than the jet pumps he was using but way out lasted them. The tank is still there after about 20 years with just a roof overhead and this is even further north that you are.

Before I could get a permit for electric, I was required to install a septic system.  So, at the same time, I had a concrete cistern installed on the high side of the house, the top of it at ground level.

Trying to figure out the details, I found this guy's pictures and explanations extremely helpful:
http://brainright.com/OurHouse/Construction/RainwaterHarvesting/

I haven't completed inside pump and plumbing yet, but the tank is full.  It's such a pain to look inside, I don't know if there is winter freeze at the surface, but it shouldn't matter.  You want your intake filter to float at mid-level, not the surface.

I've got a small collection of pdf docs I pulled from the internet, from Texas, Virginia, Australia and Alaska state entities, as well as a few from manufacturers.  
I could send them to you by email.  If you want, PM your address.

Marc Dube wrote:I dont really have any advice just experience. Growing up dad had a 8 foot deep pit dug and a normal vertically round tank 1250 gal I think was placed in this pit. We put a plywood roof over top of it. Eventually the sides caved in and left only the top exposed. At first we had it hooked up conventionally to the outlet on the bottom but eventually went with a submersible pump that sat right inside the tank. The submersible pumps are a lot more expensive than the jet pumps he was using but way out lasted them. The tank is still there after about 20 years with just a roof overhead and this is even further north that you are.

Hey Marc, thanks for the info! When you say “hooked up conventionally,” were you using a pump on the outflow side? I plan to have it gravity fed, hopefully no pump needed.

Yes that is what I ment, a pump hooked up to the outlet.