Most small-scale, residential rainwater harvesting systems we’ve seen rely on using an existing roof and downspout to collect water that would otherwise be diverted out into the environment. These are accessible for most homeowners since almost all of the infrastructure needed for it is already in place. [SuburbanBiology] already built one of these systems to take care of his potable water, though, and despite its 30,000 gallon capacity it’s not even close to big enough to also water his garden. But with some clever grading around his yard and a special rainwater system that harvests rain from the street instead of his roof, he’s capable of maintaining a lush food forest despite living through a drought in Texas.
For this build there are actually two systems demonstrated, one which is gravity-fed from the road and relies on one’s entire property sloping away from the street, and a slightly more complex one that’s more independent of elevation. Both start with cutting through a section of sidewalk to pass a 4″ PVC pipe through to the street where the stormwater runoff can be collected. The gravity-fed system simply diverts this into a series of trenches around the property while the second system uses a custom sump pump to deliver the water to the landscaping.
For a system like this a holding tank is not necessary; [SuburbanBiology] is relying on the soil on his property itself to hold onto the rainwater. Healthy, living soil can hold a tremendous amount of water for a very long time, slowly releasing it to plants when they need it. And, at least where he lives, a system like this is actually helpful for the surrounding environment as a whole since otherwise all of the stormwater runoff has to be diverted out of the city or cause a flood, and it doesn’t end up back in an aquifer. If you’re more curious about a potable water system instead, take a look at [SuburbanBiology]’s previous system.
Great build !
After reading the previous article “Hacking The Soil To Combat Desertification” on HaD, I was thinking of doing something similar on my yard.
I live in the south of France, where we have water restriction every summer now. I already collect and store the rain from my roof and this allows me to flush the toilets and irrigate a small part of my garden to grow some food.
I have the same type of yard that this guy, a small slope, and the higher side of my yard is close to the street. When we bought this house we had to dig some trenches to avoid floods: where I live we have big storms where we can get the 1/12th of yearly rainfall in just a few hours. Storms occurs mainly during autumn, and the summer is hot and dry.
Thanks to this article, I know what (and how) to do for the next months. Thanks for pointing this !
If water is such a big problem in the south of France, have you ever thought about a septic tank in combination with your own composting and water treatment?
Isn’t there someplace where capturing rainwater is illegal? Arizona? New Mexico?
Many states restrict rainwater collection:
https://worldwaterreserve.com/is-it-illegal-to-collect-rainwater/
I don’t think any states outright ban it anymore; the strictest restriction I know of is Colorado which has limits of 110 gallons. I may not be 100% up to date but the only other state I know of that has a limit is Utah but the limit is 2,500 gallons. Some other states only restrict it in that you either have to have a permit or you have to abide by some local building code. Most states either have no restriction or outright encourage it by giving away harvesting equipment. Florida especially is so flat and flood-prone that the more people that harvest rain the less stress there is on the stormwater system so they sometimes hand out rain barrels to people who ask for them.
road pollutants not a concern?
What are you using the water for, or I guess what unusual pollutant there might be on your roads are the questions there. I certainly wouldn’t suggest you drink it directly without further treatment, though like rainwater on a roof if you wait for the first few mm to wash the crap away before you store it for drinking it should be safe enough. But if you’re putting it into a soil aquifer, or tank to keep for later most of the crap will settle out and stay behind when you later put the water where you want it anyway…
Nature is also pretty good at filtering stuff out, at least if you give it the right conditions to do so.
Worst case: oil and other fluids released after a collision.
Or maybe just someone seeing the holes next to the road and deciding to dump some used oil there.
Road dirt is mostly tyre, road and break wear. https://www.sciencedirect.com/science/article/pii/S0048969724018369
All of which is likely to redistributed by wind anyways.
Compared to the impact floodings have downstream I’d say build more such rainwater sinks upstream.
I’ve done something similar with the next door neighbor – his back hard is up the hill, and he replaced all his grass with crushed rock with synthetic grass on top.
When the is a heavy rain storm I get a flood of water about 4cm deep come through.. Which now goes onto my concrete path, down a hole with a fine mesh over it, then into my 120,000l tank (the old built in swimming pool which has now been covered over the top.
Unlimited water for the garden/toilet all year around… No need to worry about water restrictions, which in Aus we have a lot…
I’ve never managed to get anywhere near the bottom of the tank, indeed a bigger overflow was the only thing extra I had to add..