A couple of years ago, I started constructing a ferro-cement tank for water storage in the shed/garage near our current home. I planned the tank to hold about 5,000 gallons, collecting water off of the roof of the building. The idea was to run a water line down the hill to the new house from this cistern. The drop in elevation between the cistern and the house would provide about 25 pounds of water pressure. We also wanted to have a cistern for collecting water off of the roof of the new house at some point.
The ferro-cement tank is only partially constructed, and time to devote to its construction hasn’t been readily available. In order to facilitate an earlier move into the new house, we decided to go ahead and put in a cistern near it. I considered options for water storage, including buying a poly tank (or more than one), building a ferro-cement tank, etc. We finally decided that buying some concrete septic tanks would not be much more expensive than building a ferr0-cement tank and about half the price of a poly tank or any other commonly available water storage tank. It also would involve a lot less time than building a cistern.
I hired a guy to dig into the hill in front of the house to create a place to set three 1,500 gallon septic tanks. We decided on three of them in order to have enough capacity to survive without rain for two to three months. July and August have been fairly dry months since we’ve lived here. So, it seemed like a good idea to plan for enough water storage capacity to not run out during dry months.
This week, after getting the insulation taken care of, I leveled out the bottom of the excavation site in order to get it ready for the tanks. I hauled in 6 tons of rock to put in the bottom for the tanks to sit on. The intention is for them to have a solid base that won’t settle and cause any of them to crack and end up leaking.
After getting the site prepared on the fourth day of the week, I called to schedule delivery of the tanks yesterday morning. We got all three tanks set in place yesterday (and then baled the second cutting of hay).
The plan now is to drill a 2” hole near the bottom of each tank in order to plumb them all together with shut-off valves for each tank. Also, the water line from the tanks into the house will come from this location. I’ll use one of the existing outlets for an overflow when the tanks are full. I’ll also construct some type of filtration system for the incoming water, which will be harvested off of the roof.
One other task I’d like to complete with the tanks is to coat the inside of them to ensure they won’t leak (they aren’t supposed to, anyway) and to prevent the water from taking on the smell and taste of concrete. I’ll be completing these tasks along with many others during the next couple of weeks.