Rainwater: It’s free, falls from the sky nearly everywhere, and is relatively pure.
Without rainwater, lakes and streams and aquifers would dry up and humans and animals would die or be forced to relocate. That’s what is happening in many places around the world today – and our species is probably responsible for these dislocations.
I live on the central California coast, and when I first moved here 13 years ago nearly 30 inches of rain was falling annually. Then a stretch of drought occurred where, some years, we got only 5-7 inches or so – barely enough to keep our coniferous forest alive. Our town of 6,400 was (finally) forced to ante up millions for a so-called portable desalination plant (so-called because it is neither exclusively desalination nor portable).
Years before, some were advocating storing water in giant cisterns above or below ground – water that would be pumped into them from our aquifers. We now have some of those in the town. On a residential level I had one in Oregon years ago, under the garage floor, pumped in from an intermittent canal (Frogs were living in the cistern, and the croaking was freaking out my young son who had a bedroom nearby!).
Rainfall is something we’ve often taken for granted, but it’s not as reliable as it used to be. Disrupted weather patterns often mean we get more rain than we can use for a short while, then long dry periods when water is in short supply. The obvious solution is to store rainwater when it’s plentiful, and use it when it’s scarce.
Harvesting the Rain
Being somewhat prophetic (which is a quality that often characterizes preppers), I began developing a homestead-wide rainwater harvesting system several years ago. The water captured would be used to irrigate my quarter-acre property, but could also, in a pinch, be used for cooking, drinking, washing or flushing toilets.
And it’s often abundant and free. When I first moved here I went to a nearby stream which was sending millions of gallons of rainwater out to sea hourly. I bottled some in a clear plastic PVC gallon container, stored it for a year in a dark closet, and then took a look at it; it was still crystal clear. Presumably whatever pathogens were once in it were probably gone (but don’t quote me on it). Even if any did survive standard purification techniques will deal with them. I continue to be amazed at how much pure water isn’t captured before it goes into the ocean…
As a young man I almost perished from dehydration trying to hike a mile straight up from the Grand Canyon from the Yellowstone River on a very hot day – all because I was too worried the water might contain giardelia. Silly me. It’s quite probable that water, running over rocks from snowmelt, was perfectly fine.
For most of you, harvesting rainwater from your roof makes the most sense. If your area gets an average of 18 inches a year, a 1,000 square foot roof can collect over 11,000 gallons of water – depending, of course, on the vessels you have in which to store it!
Keeping it Clean
Initially, rainwater collected from your roof is not pure. Bird droppings will defile it, dirt that’s been blown onto the roof will discolor it, and other organic materials will contaminate it. Also, a composition roof will secrete some petroleum-based toxins (Get a metal roof!) But after hard rain of a few minutes duration I do think a roof is scrubbed pretty clean, and I have drunk such water occasionally with no ill effects.
There are also “first flush” mechanisms to reduce detritus, which add some extra protection to your system by letting the first few minutes of rain drain away, then switching to collection once the roof is clean.
A DIY system like mine will cost anywhere from $1 to $2per gallon of capacity to set up initially, but once it’s paid for there is basically no ongoing maintenance required apart from keeping it clean.
My 2,500 gallons of storage in a variety of vessels has cost about $2,500, with the greatest cost being the 1,100-gallon poly tank that is the heart of the system. That’s sited upslope, so I can gravity feed from it to other barrels lower down.
The other vessels I have are diverse: Simple 32-gallon trash barrels, 50-gallon sealed storage barrels, a 275-gallon recycled liquid fertilizer tank, a 300-gallon stock watering tank and an outdoor hot tub that’s not regularly in use. Other ideas include an aboveground vinyl swimming pool (cheap) and a giant plastic/vinyl waterbed-type bladder you can put under your house (pricey).
If you feel good about the food you’ve stored, or the back-up power you have through a solar generating system (I’ve designed one, by the way), you’ll feel just as good about the rainwater you have – unless, that is, you live in parts of Canada or the Pacific Northwest and don’t really need it so much. But with climate change even some of those areas are even getting drier, so being able to store what rain does fall is still a good idea.
The best rainwater collection advice comes from an organization in Santa Barbara called Oasis Designs. I’ve put together a small illustrated booklet with a DVD that references Oasis and other sources for specialist rainwater system components. For example, a fine metal screen for gutters from Costco that is an absolute must if you have overhanging trees and want to avoid servicing gutters all the time . The booklet also includes the formula for calculating the amount of rain you can collect, and “35 guerrilla water saving tips.” ($20 from me at P.O. Box 1681, Cambria, CA 93428)
The photos reveal much of the hardware needed for a system. You will also need what I call “plumber’s goop” and possibly silicone sealants. Sealant is especially necessary if your system has pumps and is pressurized (mine isn’t). You will need to get up on ladders initially, but when everything is in place you’ll be doing that less frequently if at all.
If you don’t feel like doing it yourself there are contractors who specialize in rainwater harvesting, but it won’t be cheap. They are often plumbers, and you know how much they charge. But if your goal is to collect rainwater for the rest of your stay at your home, it may be well worth it. And I might add that it’s easier to install than a greywater system because the output is much more usable.
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