We live off rain water. What I mean is that our water supply comes from the rain. We do not have a well. I have no city water supply, and I don’t buy water or haul it up these mountains. Instead I constructed a DIY rain water catchment system.
We built a rain catchment system. Basically my rain gutters on the shop roof drain into big giant holding tanks. Then we drink it. Yum!
We pump that rain water out of the tanks, through some filters, and into the house for consumption.
I have not taken it anywhere official for quality testing yet, but I bet its the purest water known to man.
How To Build A DIY Rain Water Catchment System
A lot of people express surprise when I tell them I don’t have a water well. So many people comment about it that it inspired me to make this post.
Up where we live in the mountains, there are a bunch of people that truck in water in those white square tanks with wire mesh around them. Not everyone has a well. Few people even. Personally I know 2 people up this way that have bad wells – their water stinks and has a bad taste.
A bunch of people buy water and haul it in. A couple of lucky families have water on their property, like a natural creek. Or maybe a stock pond to draw from. But creeks run dry and stock ponds evaporate sometimes, so even those water supplies could benefit from catchment.
Building a DIY rain water catchment system is cheaper overall in cost when comparing to drilling a well. It’s easier maintenance and less cost than having a stock tank too. If you have a building with a roof that you can run gutters on, you can make a rain catchment system.
First you need a bunch of gutter. It does not matter if its metal or plastic or wood gutter material. Whatever is wife-approved and looks nice on your building is perfect. Hang your gutters as usual, with about 1/4″ of drop per 10′ of run to get a good flow of water going.
The Magic First Flush Diverter…
Next, your gutters will need some downspouts. You also need to rig up a first flush diverter onto the end of the spout. This is where the magic happens. You can build diverters yourself or buy fancy ones for money. They get real elaborate with floats and traps and flaps, but a simple PVC tee and some pipe will get it done. But what are they?
The function of a first flush diverter, in theroy, is that the first rain off your roof will trap in the diverter area. This rain will, in theroy, contain all the dirt, bird poop, bugs, leaves, and whatever else was on the roof when it started raining.
Once the diverter fills up, clean water will tee off away towards the catchment tanks. The diverter will keep the dirty water and heavy particles down in the diverter tube.
I used 3″ PVC as the diverter downtube, with a cap on the end that we can remove for clean outs. The tee is a 3x3x2 turned sideways. A flex drain tube is attached to the gutter downspout.
From the tee, a 2″ PVC pipe carries the water along the building side and back to the rear where the tanks are.
This section is just 2″ PVC pipe coupled together and hung slightly downhill with 2″ pipe clamps.
Rounding The Corner
I use 2″ PVC elbows and wrap tight around the corners of the building with the pipe runs. From there, using more elbows, run the pipes down to the storage tanks.
The water storage tanks in this setup are 1000 gallon tanks, for a total of 4,000 gallons of storage.
The incoming water from the gutter pipes enters into the top of either sides outermost tanks. At the bottom of each tank there is another tee fitting. Those tees connect all the tanks together via 1″ PVC and a series of ball valves along the line.
The ball valves allow me to isolate or shut off a tank from the others.
Those tees all join together at the middle of the pipe and run in between the tanks and into the shop.
I added a water spigot here with the idea I could draw from a garden hose. However there are some kind of physics going on that makes it not so great.
If I pull water here it does not flow out easily, and it makes my pump not see the low pressure kick-on point. When that happens it does not refill the pressure tank when its supposed to, and I run out of water pressure.
I have to cycle the pump on manually one time and it corrects. I think it may introduce an air bubble pocket, or some kind of pressure effect happens in the line.
Get A Big Pressure Tank…And A Big Pump. And PEX.
While I have constructed DIY rain water catchment systems previously (this is my 3rd build so far) I had never done one with full-time 40 p.s.i. pressure like what you expect in civilization.
My previous builds were a gravity fed water supply for an outhouse, and then a 12 volt DC pump solar powered on-demand or as-needed supply for an RV.
So I had some homestead learning to do about tank crosses, well pumps, and water pressure tanks. And Pex…
Pex tubing is the stuff you need. Its better than using PVC for two main reasons – flexibility, and freeze resistance. When pex freezes it does not break like PVC pipe.
The main drawbacks are that you need a special pex crimp and tool to finish them, and the cost of pex fittings are expensive. So there is some investment up front if you do not have a crimper yet.
My next upgrade will be changing all the PVC pipe to pex wherever possible. I thought PVC would be OK but the climate is just too cold here. I had no idea when I first moved up here and built this.
The water pressure tank, tank cross, and well pump are all typical off the shelf supplies.
The path of the water pipe comes into the shop from outside through the wall and up to the pump.
The water immediately travels through a “first filter” which is just a single stage particulate barrier to get dirt and pollen and whatever out.
Proceeding the first filter, the water pumps into the pressure holding tank via the tank cross. Next, from the cross, outbound water goes through an Express Water 3-stage whole house sediment heavy metal filter and is pex piped underground to the house.
Four Tanks Of Water Is Heavy
When I started this build I had no way to create a flat spot for the water tanks. So I had the big idea of building a platform in which to place the tanks on. Using treated fence plank and cinder blocks, I constructed a level platform on unlevel ground. Using fence panel was way not enough support structually. When the tanks got some good water in them it bowed the wood big time.
I have since come in underneath with more concrete blocks and 4×4 wood posts laying horiontal, trying to support everything.
Build your platform extra thick if you must have one.
Building a DIY rain water catchment system is fun, and worth the savings over the cost and maintenance of a drilled well by a long way.