Taking your rain water collection barrel one step further. Build your own urban or suburban guerilla water tower.
I made a couple rain water collection barrels for my vegetable garden. They were working out good, but I thought I could take it one step further. I wanted to come up with something a little more useful. What If I wanted to wash the car or do some other activity that requires water pressure. I fooled around with a 12 volt utility pump and it worked out, but I was still using energy to get the job done. I wanted to make it greener and I wanted to make it as simple as possible by using gravity.
I was cleaning out the attic and came across our old water bed. I was about to list it on freecycle when the lightbulb went off. What if I could put this on the roof and fill it with rain water. I worried about the weight on the roof, but this past winter we had 3 feet of wet snow on the roof and it held the weight. I’m no engineer, but the waterbed can’t be as bad as all that snow.
I have a three story house with a one story addition on the front. I placed the bladder on the roof of the addition and use the second floor gutter to fill it. I wanted to use some sort of filter to prevent debris from entering the bladder. I didn’t want any thing to clog a hose nozzle or sprinkler. Adding a filter means that I need some head pressure to push the water through the filter. I cut a length of 3 inch pvc pipe as tall as I could and still have it fit under the gutter. I capped the bottom end. I drilled and tapped a fitting near the bottom to attach a whole house water filter. At the top of the 3 inch pipe I added a tee and a 90 degree fitting to allow the overflow to escape during a heavy rain fall or when the bladder is full.
As the rain begins to fall the 3″ pipe fills creating some pressure on the filter to allow the water to pass. I believe you get about .5 psi for every foot of head. If the 3″ pipe fills the runoff passes through the tee and off of the roof. The rest is pushed through the filter and stored in the bladder. My filter is just some left over window screen wound into a cylinder. I don’t need to make purified drinking water, I just want to keep out debris. Washable stainless elements are available for some filter housing.
I added a tee and a shut off valve after the filter. The tee allows a garden hose (or plumbing of your choice) to connect your bladder to your garden. The valve allows me to service the system without draining the bladder. If I notice that the bladder is nearly empty I stop using it. I need to keep some weight in it so a strong storm won’t blow it off the roof as it’s not mounted in any way. I did have some concern about how well it will hold up to uv light, but time will tell. If it does break down it’s not much loss. After all I was going to get rid of it anyway. If it works out I can come up with a protective cover next year.
The low profile of the bladder makes this pretty stealthy, but you could build the same thing with a couple plastic barrels from your local car wash. I have city water where I live so I can’t plumb this into the house, but if you live off grid or have a well this system can provide water for washing or flushing toilets with out the cost of running your well pump. Of course you don’t need to copy my system exactly. Just use it as a guide, make some adjustments and call it your own.
Use caution, do not overload your roof. Water is about 7 or 8 pounds per gallon and it can add up quick. The barrels or bladder doesn’t need to be on your roof. They can be supported off the ground with a wooden or steel frame. They can still be filled by plumbing them into your gutters. In a camping situation an elevated barrel could be filled by stringing a tarp between some trees, poles, vehicles etc. Drain the tarp into the barrel and you have a rain collection system.
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