Harvesting the Rain

Last weekend we installed a rain barrel off our henhouse roof. Granted, based off our non-exsistant winter we had, it might never rain again. But last year it POURED for almost all of March, so I’m being optimistic ūüôā

Rainwater harvesting is not only cool, its also a very smart idea. It can reduce our need, and our demand, for water from the municipal supply.¬†The infrastructures that bring us this water costs billions of dollars in public tax money and household utility bills. Water that comes from the sky is free. Rainwater is the closest thing you can get to “pure” water. However, it can pick up contaminations from the roof or the containers its stored in, so you wouldn’t want to drink it without an advanced filtration system.

In Northern California, we normally receive the majority of our rain during a 4 month wet season, so its crucial to capture as much as possible to use during the 8 month dry period. Harvesting rain isn’t a problem, but storage is. To store enough water to reduce your dependency of water from a well or municipal system would be almost impossible. Tanks are expensive, large, and take up lots of space. The barrel we set up is only 55 gallons, but I’m big on the “anything helps” philosophy. 55 gallons isn’t much, but is 55 gallons less that came from the tap.

We will use this barrel to fill up a watering can to get to the corners of our yard where the hose doesn’t reach. Its also nice to know that in an emergency, we have a water supply. Sonoma County only has a 3-day emergency supply of water stored. Harvesting and storing rainwater is crucial to create resilience.

You can buy rain barrels at hardware stores, but they are plastic and look like a trash can. I like to reuse things. We got a 55 gallon metal malt drum from one of Matt’s customers:

First step was to clean it out. I was grossed out by the stickyness, so Matt scrapped it out then cleaned it with a bit of Dr. Bronners and hot water. It smelt exactly like the grain I fed to the horse. We mixed it with scratch and fed to the chickens.

The key parts of a system are the barrel, a hole for the water to enter, a spill over pipe, and the water spigot. Its also good to have a way to divert the water from catchment for the “first flush”, or to not capture the first rain, as it will be cleaning off the roof. We will just manually close the barrel. Home Depot sells packaged fittings for the spigot situation, called a bulkhead fitting, which is a a male fitting, 2 gaskets, and a female fitting. A hole needs to be drilled that fits the male fitting, the spigot screws into that, and the female fitting tightens from the inside of the barrel.

Our barrel’s lid already had a hole on the top in the lid, so we worked on the hole for the spigot and the spill over. We thought we were being brilliant by using a 3 inch circular drill bit, but failed EPICALLY. It works great on a plastic barrel, but not on metal. The bit just bounces around.

Enter DREMEL! We use the cutting bit to make a 3″ circle, and then the sanding bit to smooth out the edges. You want to make the spigot a few inches above the bottom, so silt and dirt can settle.

Once we had all our fittings installed, we made a “foundation” of some cinderblocks. Because our henhouse roof is pretty low, we dug the earth out a bit so we could get a watering can under the spigot. Once they were level, we aligned the barrel under the gutter hole. I cut up an old plastic container to make a funnel to direct the water into the barrel, and covered the funnel with an old nylon to strain out dirt.

Even with only a few rains, this barrel will fill up. To calculate how much water a roof top surface can harvest, factor the catchment area x rainfall (ft) x 7.48 gal. Our hen house roof is about 5 x 6 feet, so a total of 30 square feet. Thats over 224 gallons from that one rainfall. We hope to get a few more barrels and create a chain before next year’s “winter” starts.

Sonoma County, where I live, harvesting rainwater is legal, and even encouraged, but depending on the city, large tanks may need a shed- type permit or meet setback requirements.

However, the current California greywater and rainwater harvesting code is at stake, and is proposed to be replaced with overly stringent requirements- which would make many back yard rain barrel and cistern systems illegal. You can learn more and take action at http://greywateraction.org/alert/2012/03/01/ca-greywater-and-rainwater-code-stake¬†Even if you are out of California¬†State, consider support this cause, as this proposed code is part of the “Universal Plumbing Code” which is adopted by many states in the US.

7 thoughts on “Harvesting the Rain

  1. Very nice post! I enjoyed that greatly. We have a huge roof and have considered installing a rainwater catchment system to supplement watering of landscaping. Our water comes from a deep well. It requires electricity to pump it to our home, so we rarely rely on our automatic sprinkler system (which throws out 100’s of gallons per zone) to water plants. We prefer the “natural” method (i.e. rain) and spot watering (i.e. slow soaking specific plants). Catching rain just seems like a no-brainer.

    Here’s another great resource of information from my state of Texas. It also may be helpful. There are some formulas for planning purposes in there that I found useful.

    Click to access RainwaterHarvestingManual_3rdedition.pdf

    1. Thanks for that link, Shannon! Lots of good info. Not sure if you can find it out side of California, but Brad Lancaster has a great book on harvesting, also.

  2. Hi there! I was excited to find this blog via Remodelista. I live in Sonoma County also and am wondering if you’d consider selling any additional rain barrels you make? Since you have all the tools and have much such an excellent prototype, I would be interested in purchasing 1-2 of them.

    Thanks so much!

    Kathy skdoig@sonic.net

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