Cistern hooked up

Last summer, we buried three 1,500 gallon septic tanks (new ones) in front of the house to serve as a cistern for rain water collected off of the roof of the house. I also contracted with a local company to install 6-inch seamless gutters on the house. However, it took them a year before they came and completed the job. Thankfully, I wasn’t in a hurry. I patiently waited for them to do the job, calling them occasionally to find out when it would happen (it was almost always, “the first of next week unless the weather is bad”). Yeah, I could have hired someone else to install gutters, but the quote I got from this company was $700 cheaper than the quote I got from another company, and it cost less than what it would cost for me to install gutters.

Anyway, they showed up in late June this summer and installed the gutters. It took me until the last part of August to finally plumb our water collection system from the downspouts to the cistern. It wasn’t difficult. Basically, I ran 4-inch Schedule 35 sewer pipe from each of the four downspouts to the cistern. I installed a roof washer on the east side and on the west side of the house.

The roof washers purpose is to divert away from the cistern the first 100 gallons of water that come off of the roof in a rain storm. This allows dirt, bird droppings, and other contaminants that may have accumulated on the roof to be washed off with the beginning rain and not end up in our household water.

I contemplated upon how to design the roof washer system for the house. The design I settled on uses a 55-gallon barrel for each one. As water flows from the two downspouts on either side of the house, it flows into the barrel on that respective side. I used 2-inch PVC to connect to the barrel with a home-made floating ball valve in the line. The initial rain off of the roof will not generally be more than the 2-inch pipe can handle. The water flows around a ball contained in the space inside two 4-inch to 2-inch reducers. When the barrel is full, the ball floats upward and closes off the entrance for the water into the barrel. This is to help insure that nothing in the barrel can be washed out and back into the line to the cistern.

For the floating ball valve to work, the barrel must be sealed. The water and little bit of air left in it when full keeps the ball from sinking, effectively closing the inlet to the roof washer. I laid the barrels on their side so that water flows in through the top bung into which a regular 2-inch threaded PVC connector threads (2-inch NPT). The other bung which has different threads (very course) can be opened to drain the water out of the roof washer barrel after a rain shower. This system collects about 50 gallons on each side of the house before the water proceeds to the cistern.

We’ve had nearly 3 inches of rain during the last two weekends. I previously calculated that it would take about 2.5 inches of rain to fill the cisterns. My calculation was very close. The cistern was full and overflowing somewhere around 2.6 inches of rain. The overflow runs from the cisterns to the pond through a 100-foot section of 4-inch corrugated drain pipe.

The last thing I did to ready the system for water collection was to install 1/2-inch hardware cloth over the gutters. I bought 3-foot by 10-foot rolls of galvanized hardware cloth and cut it into 8-inch widths with a metal cutting blade. I inserted one edge two inches under the roof metal and attached it to the top of the outside edge of the gutters with self-drilling machine screws ever couple of feet. This keeps most of the leaves out of the gutters and out of the cistern. A few leaves that get through will end up in the roof washers. The rest of them are screened out before the water enters the cistern (it’s run through window screen). Before we use the water in the house, it will run through an inline screen filter, and all drinking water will be filtered with a ceramic filter or a reverse osmosis filtration system.

Tanks for the water: part two

Although the cisterns are not collecting rain water, they are mostly ready to do so. We don’t have gutters on the house, yet – I’m waiting on the installers. Based on the bid I received for seamless gutters, it’s actually cheaper for me to let them install them than to buy and put up gutters myself. So, as soon as they schedule their crew to come do the job, we’ll have the house guttered. In the photo, you can see that I painted the fascia. This is the color that the whole house will be painted eventually.

I’ll detail later the construction of roof washers and screen filter that I’ll construct. The roof washers will divert the first several gallons of water coming off of the roof whenever it rains. The intention is to let the first bit of rain wash dirt and debris off of the roof so that it won’t end up in the cistern. The water will run through a screen before entering the cistern in order to keep leaves and things that get past the roof washers from being in the harvested water. The water should be clean enough for general household use, bathing, washing dishes, and laundry. All cooking and drinking water will be run through a ceramic filter first.

After we had the three tanks set in place, I rented a drill with a 3” concrete bore bit. With my dad’s help, I drilled a hole about two and half inches off of the bottom of each tank. The septic tanks are only set up with inlets and outlets near the top of the end walls. With the holes lower, I was able to connect the tanks to one another so that they will fill and empty as one tank rather than three individual tanks.

The three inch hole was a little over 1/2 inch larger than the exterior diameter of 2 inch PVC. So, I used some 1/4 inch Plexiglas and silicone caulk to seal these outlets. I used an 8 inch piece of 2 inch PVC (actually electrical conduit, but it’s the same thing as used for water, only a different color) threaded on both ends. The threaded fittings on each end tightened against the Plexiglas and sealed the holes around the pipe.

When I plumbed the tanks together, I put in ball valves on each tank so that I can isolate each tank separately for cleaning whenever deemed necessary in the future. I also plumbed in a drain line. I put all of these valves next to one another so that I will be able to access them easily. The tanks are in the hillside in front of the house, and there will be dirt completely covering them. On the down hill side, I will terrace the slope with beds for flowers or whatever so that it won’t be too steep. In one of the terraces I will have an access to the valves, about 36” deep inside a plastic barrel I cut the ends out of for this purpose.

I took the two inch line from the tank outlets and ran it into the crawl space of the house. I also teed off of it for a 3/4 inch line which I also ran into the house. The 3/4 inch line will supply the water to the pressure pump and the 2 inch line will be for installing a pitcher pump in the house and to provide the opportunity for additional pitcher pumps later on if necessary.

Since I was concerned that if we received a heavy rain during which water might flow into the cisterns faster than the 2 inch line connecting them together could keep up with (leading the first tank to reach full and need to overflow before the other two tanks), I connected the tanks together with 4 inch pipes at the level of the inlets on the side near the house. This ties the tanks together at that level and then serves as the overflow which will be run to the pond.

I used my loader tractor to push dirt around and onto the cisterns once I had them plumbed together. I still have to manually move some of the dirt since I don’t want to take the tractor on top of the tanks. In order to get them covered properly, I’m going to need some more dirt, which I have on the east side of the house. I’ll have to relocate a few things that are in the way before I can begin to move that dirt in order to finalize the landscaping around the cistern and generally in front of the house.

After more research, I decided not to put a coating on the inside of the tanks. It could potentially lead to more problems than plain concrete would. I cleaned the interior walls as well as I could, and I think they’re ready for water.

Tanks for the water

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.