| | Harvesting Rainwater
As with so many aspects of our lives in which we harvest and store things for later use, Larisa and I (Bob) have been harvesting, storing, and using rainwater for all of our water needs since 1984. We also collect and store the following: * Fallen trees, as firewood, for home heating, hot water, cooking, and saunas. * Electricity, from photovoltaic (PV) panels, stored in batteries, for all electrical needs, including hot water backup. * Food, preserved by solar dehydration, steam juicing, steam canning, and root cellaring. * Heat, stored in a 2-ton masonry woodstove and in the 30-ton masonry floor of our passive solar, strawbale insulated home.
So many people are connected to municipal water sources and individual wells that they are led to believe that water is in infinite supply. That's far from true, as the news stories on polluted underground aquifers and above-ground lakes and streams make stridently clear. And you've no doubt heard about the climate-change-related droughts occurring in new locations worldwide. So if you're the sort of person who takes 2 showers per day, plus a load of clothing in the washer, and just can't get along without a flushable toilet, this may not be for you! Of course, if you live in an area with dairy operations, you can often hire a milk trucker to bring you a 3500-gallon load of water and fill your cistern for a nominal fee, but then you don't get all of the benefits of rainwater. It's just cheaper than drilling your own well.
As a township officer in Minnesota, Larisa attended a County Township Officer's meeting where a rainwater researcher gave a presentation. She obtained sampling data for our State that proved two things we had always suspected: * Rainwater is both far "softer" (fewer dissolved solids) and far cleaner (in terms of man-made chemicals) than surface or groundwater aquifer sources. * Rainwater is even more clean when collected in very early Spring and late Fall, when agricultural activity, with its inherent baggage of man-made pesticides or stirred-up chemical laden soil, is at its lowest ebb.
 We collect our water from the roof of our 1000 square foot, single story home. The roof is a simple, galvanized steel shed type, found on many agricultural buildings in our area. The shiny surface deters birds and their associated "debris", it's widely available, low in cost, easy to install, it rinses clean easily, and it lasts a very long time. The ideal rain collection surface would be stainless steel but that material would lack a couple of these virtues (mainly cost). Before we collect rain, I reach up and use my hand to remove any leaves or maple seeds from the "gutter". Then I wipe the interior clean with a terry-cloth towel. As you can see, a shed-roofed house has a gutter tha's very easy to reach without a ladder.
We collect rain for household use only a few times in the Spring and Fall. Waiting for the forecast of a heavy rain, we first let the roof and collection gutter rinse in a steady downpour for about 5-10 minutes. Bob then sprints outside to the back of the house where there are 3 sink stoppers in the galvanized gutter that determine the water's destination: * a "water run" leading to a pond. * An above-ground, 1500 gallon, polyethylene tank to store water for emergency garden irrigation (soon to become 2 tanks, using drip irrigation) * An above-ground, 250 gallon, stainless steel "settling tank" which overflows to our buried, 2500 gallon, stainless steel, milk truck tank.
 This is the settling tank that gives collected rainwater some time to settle the dust that is the nucleus of every raindrop. An inch-and-a-half diameter polyethylene "standpipe" in the tank connects to the tank's drain. When the tank overflows, the water flows down into our 2500-gallon main collection tank. You can also see the other black polyethylene pipes that feed the pond and the 1500-gallon irrigation tank.
So anyway, at some point Bob switches from filling the pond to filling the stainless tanks or the big plastic irrigation tank. On the stainless settling tank, water flows through a very fine mesh stainless filter screen, then fills the upper tank, then overflows to the buried tank. Water flows from the big buries stainless tank to our house by gravity, through a 1.5-inch polyethylene pipe, where it reaches the intake of a 12-volt, DC pump. This pressurizes the water to 35-55 psi for household use. Bathing, laundry, and houseplant irrigation use no further filtration. Cooking, drinking, and dish washing use carbon block filtration at the sinks.
 This photo shows the three sink drain "tailpieces" feeding into the three options. We just move two rubber stoppers around. One drain always remains open.
Very little soap is needed for laundry, bathing, or dishes since there are almost no dissolved solids to interfere with sudsing. And everything rinses much easier for the same reason, leading to less water use. Over 25 years of drinking and cooking with rainwater while enjoying excellent health sort of speaks for itself.
The 2500 gallons we store for household use is easily enough for 2 people for an entire year, as long as you use a composting toilet instead of a flushable model. To determine how much rain you'd need to fill a tank this size, start with your roof's area. Ours covers 42 by 30 feet, or 1260 square feet. An inch of rain on 1260 sq. ft. is 1260 times 144, or 181,440 cubic inches of rain. There are 231 cubic inches in a gallon, so 181,440 divided by 231 = 785.45 gallons. So a 3.18 inch rainfall will fill our tank (2500 divided by 785.45 = 3.18). You can simplify the math by figuring that 1.6 square feet of flat roof will yield 1 gallon. To convert your roof's sloped area to flat square footage, just look at how much ground area it actually covers. Then just divide that area by 1.6.
 This series of photos starts with our sheep shed seen from the North side, showing the rain collection gutter below the roof edge. The area covered by the roof is 27' by 23'. The square footage covered is 621 sq.ft. So in a 1-inch rain, 621 divided by 1.6 = 390 gallons.
 This flows to the end of the gutter where a rubber adapter clamps to the gutter outlet and moves into inch-and-a-half black polyethylene pipe. A 2" by 6" piece of 1/4" "hardware cloth' is rolled into a 2" tube and inserted into the gutter drain to catch debris. But since it isn't as tall as the gutter, it allows water to overflow a clogged screen and continue to fill the collecting tank after the initial debris removal.
 The water flows down into a 1500-gallon polyethylene tank designed to hold "farm chemicals". On top is a 1/2 Hp AC pump that pressurizes the water, moving it uphill to our garden. The output of the 1" poly pipe is split into four 3/4" rubber hoses for zone waterring without having to move hoses around very much. The black poly pipe heading left is an overflow that drains to the pond in front of our house
 This is the final output in the main garden, during the 2007 growing season. There is a shut-off at the base of each "watering wand", ending in a fan-shaped spray head. With two wands in operation, the spray reaches out about 10-12 feet. With only one operating, it reaches close to 20 feet. This has now (2008) been modified to switch from pressure-pumped spray watering to a full drip irrigation system using recycled rubber hoses in each garden bed (1450 feet of hose in individually switched 50-foot lengths). One 1500 gallon tank is placed at an elevation above the garden, connected to the drip system for gravity feeding. The current AC pump and 1500 gallon tank is used to store roof-collected water and pump it up to the gravity feeding tank when we need to drip irrigate.
How much do we need for irrigation?
An acre of ground is 43,560 square feet. For optimum growth in our region, we need about an inch of rain per week. An inch on an acre (acre-inch) is 27,154 gallons. so our 0.1 acre garden needs about 2,715 gallons if we do overhead, rapid watering, or, using the drip lines and irrigating only the 2-foot wide strips around the drip hoses, we need 1,808 gallons/week.
More photos of rain collection:
 The sheep shed has a "wing" on the East that continues into a woodshed. The area covered by this roof is 192 sq.ft., and a 32-foot gutter collects this into a 250-gallon stainless steel dairy "bulk tank" to provide water for sheep, spot watering in the garden, etc. In a 1" rain this roof provides 120 gallons of water (192 / 1.6 = 120). Shown is the 4-inch PVC pipe that feeds into a small stainless sink with a window screen stretched across the top. The sink "tailpiece" drains directly into the tank. A 1-inch poly overflow "standpipe" is connected to the tank's drain so that any excess goes into the 1500-gallon poly tank below it.
 This shows our 2500 gallon stainless tank in the process of being insulated. It wasn't buried quite far enough for the 6-foot frost depth we sometimes encounter, so it's first covered with fine gravel, then 2-inch extruded foam insulation. Over this there's a plastic tarp, then a few inches of gravel again.
 This shows the final view of the buried stainless tank, with its insulated aluminum access cover sticking up from the gravel. Also shown is the 1500 gallon polyethylene tank with an AC pump above it, used for irrigation (before it got a coat of plastic paint to cut light entry into the tank which causes the growth of algae).
That's all for now. Happy Harvesting! And if you have additional questions, you can use the contact information found on our Home Page.
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