Automated Rain Barrel Watering System

[Dmritard96] built this automated watering system to keep his garden growing while he’s out-of-town. It uses rain barrels, which capture and store rainwater, as a source. These barrels provide very low water pressure so he’s added a battery-powered pump along with a solar array for recharging. Don’t worry, if the rain barrels run dry there’s a float sensor that will switch the system over to city water and stave off those wilted leaves.

33 thoughts on “Automated Rain Barrel Watering System

  1. “city owns any rain”

    It’s the state, not the city, and it’s only in two backwater redneck hick-ass states: Colorado and Utah.

    Personal use rain barrels are legal in Washington state, it’s only larger ‘systems’ of collecting barrels and huge resevoirs that need special permission. With the sheer amount of rain in WA I’m surprised they even bothered.

    You can fix pressure issues without a pump by elevating the barrel and using a larger diameter feed tube.

  2. I lived in CO for a while and it wasn’t even your state that owned the water falling on the roof but the state the runoff leads too.

    Since moved to WA where rain barrels are encouraged given the money spent on storm water drains etc even places where you can get subsidized rain barrels (though still outrageous prices for a cheap plastic container)

    As fot the project this is totally on my list.

  3. Pretty sure that even if the state tried to claim that the rain is ‘their property’, I’d have to go ahead and approve of this project.

    Although I suppose I don’t own the ground I walk on or the food I eat, either.

    Sucks being a lowly serf…

  4. I’ve been planning on making a setup like this for my garden. The only problems I’ve had is how nasty the water gets after a couple of weeks of warm weather with the bugs, algae, mildew, etc. that build up. Adding too much chlorine to the water can change the pH of soils which can cause problems with certain plants. Determining the level of chlorine to add every time it rains can be exhausting and expensive.
    It’s a good thing I have such a nice neighbor who’s always looking for something to do. She’ll water the garden while we’re gone for more than a couple days if we ask her.

  5. @Yosh – the solution the the algae and mosquitos and so forth is fairly simply. You collect the rainwater and route it into COVERED barrels. No light = no algae

    Humans have used cisterns to store potable rainwater for thousands of years.

  6. I have a system like this on my house, it collects rainwater, lightly filters it, stores it in a tank of approx 2 cubic metres and then uses a demand-based pump system to push it up to the attic tank. From here it feeds the washing machine (clothes) and the toilet. Considering our water is metered, it saves about £100 UK per year. IT uses a little intelligence to only pump when the top tank isn’t full, and if there has been no rain in the main tanks on the last pumping request it adds 5 hours onto the time before the next test. I’d have liked to have volume monitoring for the pump/demand system but I felt a more failsafe approach was to use float switches. Seeing as our watering system is mains-fed, it would be a piece of cake to add that onto the outputs and control the lot with the same processor.

  7. if you connect rainwater and city water to the same pipe, add a backflow valve. some cities require it, but it is a good idea in general. otherwise, in case of a city water shutoff, your rainwater might drain into the system.
    if you don’t want to spend the $20 for it, add a toilet tank valve to the rain barrel and rig it so that it adds a couple inch of water once the barrel gets empty.

  8. A few comments..

    First off.. sweet system.. but the barrels seem high enough that no pump should be needed.. unless he has a spray delivery system. A drip system would be better and should require no pump if laid out correctly.

    yosh – water should not be sitting around for weeks. If you make this the main watering system, you should always be using water from the covered collection tanks. If the tanks run dry, fill them with city water.

    One other savings here.. in some communities, like mine, sewer charges are based on water consumption. So, if it isn’t metered, it isn’t costing you any sewage charges.

  9. Gotta say first off that this irrigation system is right thinking at the right time. Good on you. The second thing is that, and very typical of hackers everywhere, several people here took a good idea and contributed their ideas with the intent to make the system even better. Very cool bunch of people. Thanks.

  10. I live in CO and was planning to utilize a very similar system until I found out I could get fined (even jailed) for collecting rainwater.

    Certainly a VERY retarded law…I guess it’s because we need water on backup every time California faces a drought.

  11. Instead of designing for water delivery using pressure, as in this system, a simpler approach for small plots may be to design for a free-flow system that waters a bit more slowly with no pump and nil pressure. Low pressure irrigation won’t be as efficient with water usage as the pressurized drip systems used in arid reigons, but low pressure/free flow will surely be simpler/cheaper to build and maintain. In place of presurized smaller pipes, unpressurized larger diameter pipes are used to get water to where it is needed. The larger diameter piping is actually cheaper since it can be very thin walled. This type of system is pumpless so it needs only a very tiny solar panel and battery to run a timer and solenoid valve.

    I guess it should be mentioned that there is a requirement to make sure there is even flow throughout a low-pressure distribution system. Relatively large diameter feedline is run from the rain barrel and small diameter supply tubing is plugged into it (hot glued?). So long as the open ends of the supply tubes are staked at equal elevations, each supply tube end will provide the same volume of water as it’s neighbor. Equal elevations = equal flow. Need more water in one spot? Just lower the open end of a supply tube. Need still more? Plug in another tube or switch to a somewhat larger diameter tube. The overall watering that takes place is faster than drip systems but slower than sprinklers & sprayers.

    If water has to flow uphill or over a distance, irrigation water should be distributed from an elevated rain barrel and/or fed into a low-pressure pump. If a pump is needed, a high-pressure (70 PSI) diaphram pump as mentioned in the documentation takes a lot of power to run and would be a serious mis-match for free flow irrigation. A small centrifugal pump is energy-efficient and will do the job very nicely, plus centrifugal pumps cost less, last longer, and require nil maintenance when compared to diaphram pumps. Another benefit is that the watering controller designed by Dmritard96 can now switch to a smaller/cheaper battery & solar panel system to feed the much smaller pump.

  12. So, the State of Colorado has passed a law (Senate Bill 09-080) that makes rainwater the property of the State. The total amount of rainwater collected even if all homeowners used a rooftop collection system is an impossibly small fraction of the rainfall over the rest of our State. This, of course, has nothing to do with California or any other state, but CO’s voting citizens are responsible since they voted for the people who wrote this weird state law. Maybe, finally, more folks in CO will register and do some actual voting — this time to replace the people who created this ugly law. We need to use natural resources as they come to us from nature. It makes no sense to have a law which actually mandates that CO residents can only use rainwater if they purchase it out of a pipe after huge amounts of energy are spent in collecting it and pumping it back to where it came from. Mebbe it’s time to move.

  13. I would happily give Utah, Colorado, and Washington State, and Washington D.C. my left over bladder water. Happily, these states will not require any complex collection system, as their backs will do nicely. Failing that, their faces will suffice.

    I don’t really blame the citizens of these states, but more the special interest groups and corrupt politicians. The companies usually come in at night, wave money in the faces of legislatures and viola. Yes the citizens do vote them in, but most of the time, it is the politician who does not live up to the standards he/she used to get into office.

  14. If Colorado, Utah and others have made it a crime to collect rain water, than what happens if you go outside during a rainstorm, open your piehole, and drink the rain as it falls? Are you not “collecting” rain water? Therefore, have you now broken the law?

    What about a wet umbrella? Didn’t it “collect” rainwater? I suppose if you were a real outlaw, you’d take the umbrella indoors, fold it up, and spike the tip into a potted plant, so that the plant could capture whatever drips off as the umbrella dries. On second thought, forget it. You don’t want to end up on a terror watch list.

    If politicians can get away with this sort of thing, can an “oxygen consumption tax” be far behind?

  15. Back on the topic of mosquitoes and algae growth. Covered Opaque barrels should do the trick. If you are using barrels that do pass light through, a simple agitator, or recirculation system should keep the algae from growing too much. All you need is enough agitation in the water to unsettle the surface, that would keep most flavors of moss and algae from growing. It would also keep most of the mosquitoes out of it, as they don’t like to lay their eggs on turbid water.

  16. This post was about the irrigation setup. This collected rain water may not be “potable” in terms of direct human consumption, but if may be just that, no information given on the collection system, and if irrigation only was the planned use, no need to go through the extra steps to in sure the collected water is potable.

    @skipper; tantris As I read the project, the pump is needed because the system uses the city water for a back up, so the actual irrigation plumbing has to be fitted to the city supply, and the rain water collection has to be matched to the irrigation plumbing. However a gravity system with a city supply backup could be as simple as having the city supply fill the barrels when the water level in them drops. Also there’s a practical limit as to high the the rain barrels can be, so a pressurized system is pretty universal in it’s application
    As far as I know small water catchment systems are legal in KS. Apparently in KS cities are allowed to modify streams flow to fit their needs, but farmer FAR upstream can’t. KS has sued both CO and NE over the amount of water both states hold back from KS. Rain belongs to those down stream as much as it does up stream. Whenever this topic comes up, I’m surprise of the number of people ignorant of the events that lead to law that many find difficult to understand. yea the law needs to be changed, but, no one really want’s to open the water rights can of worms, so the best thing to to is to ignore small residential water catchment consumed on site. The two things that may really effect our water supply is the push for the privatization of water systems, and climate change. Climate change is real and has been ongoing. The old timers have noted it, but simply say the weather has changed. PLEASE note I didn’t mention why the climate is changing. :)

  17. Relating to gravity feed…The barrels (there are actually a number of them strung together) are about a foot off of the ground and because there was an existing drip system (designed for use with a city water [~40psi]) gravity won’t put that kind of head on the spigot at the bottom without them being significantly higher (the pressure is a result of only the water column directly above the outlet I think???). While a more passive system would certainly be cheaper, a safe structure to hold a drum (actually 8 drums) that size full of water would not be cheap. I built this to help my old highschool with a sustainable agriculture project and I didn’t think our county schoolboard would be thrilled with building water towers either.

    @tantris: I didn’t really even think about backflow but wouldn’t the solenoid take care of that? If not do you know what the proper way to do it is?

  18. I think you would need a pretty high-end back flow prevention valve like a double (not dual) check back flow preventer to be safe here. Relying on the solenoid valves is not sufficient and an anti-siphon solenoid valve would not work properly with the pressure produced by the pump. The solenoid valve is not sufficient it will leak at some point. So if the city water pressure drops, you would be pumping grey water back into the city system.

  19. @dmritard96
    right, the solenoid together with the mains pressure normally take care of it. but i agree with epooch: a backflow preventer keeps the water supply save even if city water is out and the solenoid fails (back siphoning). with your setup you could also end up with backpressure: if the irrigation hose gets twisted or blocked, the pump will work against the mains valve pumping water towards the water supply.
    you can find something called a “hose bib vacuum breaker” for $4-$8 at your hardware store. i don’t know if that would be enough with your setup. they are are just for garden hoses, not for a system with a pump.
    a cheap and good alternative to a backflow valve is an air gap setup where the water supply line comes in higher than the highest possible fill-line of the barrel. (that’s also how washing machines are set up.) with your setup i would have the city water go to the rain barrel. whenever the rain barrel runs dry, a few inch of city water are added. the hose with the city water coming in should be further up than the rain barrel overflow, so nothing can get siphoned back out (air-gap system). you would need the pump all the time, but with solar that should be fine.

  20. Dang, y’all, yer gettin’ super geeky on me, but I’ll try to keep up. I had just watched a how-to on making rain barrels (on local cable Ch. 11 in Portland/Vancouver) and then saw “Blue Gold” docu re: world water crisis. Woke me right up. Yes I WILL look into setting up a rain catch system. Thanks for all of your great ideas!

  21. There are so many cheap, easy, and even free ways to collect rainwater, it’s a shame that more people aren’t taking advantage of them. Heck, even if you just set out some buckets for watering plants and gardens, you’re doing your bit to help the environment. I know that’s not an ideal way to do it, but anything people can do to get started is a good idea. And a simple catchment system can be made for almost nothing.

  22. V low pressure gravity flow systems have been studied and are just one more science. Made one. Interesting…! One basic is 27″ of water column yields a psi. And those Aussie spiders love to rest IN water. Redbacks. Flip a Black Widow o er and amp-up the toxin. 15 minutes to antivenom or bye bye.

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