Are you looking to create a completely off-grid rainwater harvesting system? Want to eliminate the need for an electric pump?
If you answered "yes" to both of those questions, then an elevated above-ground tank may be the solution you are looking for. Elevating a water tank increases the available water pressure and lessens (or eliminates) the need for pumping. For every foot of elevation of your water, you increase your water pressure by a factor of 0.43 PSI -- the higher you elevate, then, the more water pressure you get.
Our experience has shown us that you don't have to have a backyard water tower to create a usable rain system. Quite the contrary: Even elevating the tank a few feet drastically increases the functionality of your rain system.
Years ago, we developed a design for a platform for elevating an 1,100-gallon rainwater tank for a Mennonite Church here in Columbus, Ohio.
Above is an image of the platform post construction. The 2x4s leaning on the platform are used to roll the tank onto the platform once the groundwork has been completed.
We have now decided to release our design for educational purposes only. You are welcome to reference it, but please consult a structural engineer before constructing a platform for your tank. To view our design, click here.