Hey, JF, can cisterns be used in regions subject to frost?
A well is on my list, and we have 220 gals of rain barrels on hand, but not in the winter. I'll keep 'em inside this winter and treat for storage, rotate if need be, but a cistern seems like time and money well-spent.
And the tunnels may hafta' wait till after the big to-do and responsible people are in charge.
Bury it below the frost line.Temp 6/8 feet down stabilizes at about 55 degrees.
But is you have a well and a power source(generator) the cistern would be a back up to that or use it to catch rainwater for irrigation and drinking if need be with the proper sanitation steps taken.
