It's absolutely ironic that I opened my mailbox to see the title story of On Earth, "Running Dry: From Lima to Los Angeles, the survival of great cities around the world depends on sources of water that are dwindling at an alarming rate."
Ironic, because for two days, we have had nothing but rain. Until it began snowing. You get the idea---lots of precipitation!
Water is among our most basic needs as humans. From the earliest cultures who toted water from a nearby river or stream---to today, where many in our country rely on the convenience of a faucet and a public water supply, water is the one resource we simply cannot do without.
When Fred and I were in the planning stages for Haven, we played around with many ideas for reducing our daily impact on the environment. One idea that stuck was the idea of using a cistern, a way to catch the water from our roof and store it for future use. We had seen cisterns during our trip to Bermuda, where catching your rainwater is the norm, but we knew nothing about the logistics---or legal issues---surrounding cisterns. (Here in Pennsylvania, no one cares if you harvest your rainwater. In some western states, where water is a very precious commodity, laws have been on the books for the past hundred years addressing water rights and prohibiting rainwater harvesting.)
Our biggest hurdle was learning about the ins and outs of rainwater collection. What type of roof would we need? How much water would we need to store? Where would we store the water? And in what? How would we treat the water for safety?
Most of our answers came in the form of wisdom from Suzy Banks and Richard Heinichen, from their book titled Rainwater Collection For the Mechanically Challenged. That was us!
Suzy and Richard's book walked us through building our system from start to finish. They explain how to plan for storing an adequate amount of water and help you decide which type of tank to install. Suggestions are offered for the site (location) of your collection tanks, and overviews are given for different pumps and filtering systems.
How does our cistern actually work?
When it begins to rain at a conventional home the water is collected into gutters, travels through the downspout, and is funneled away from the foundation of the home. Here at Haven, it is the opposite. Our water collects into gutters, travels through the downspout, and is funneled into holding tanks in our basement.
At the start of a rain shower, the water is funneled first into a tank called the roof washer. (Any pollen, caterpillar poop, etc, gets washed in there too.) This gets all the crud off the roof before we begin to catch the water we'll be drinking. Once the roof washer is filled, the water begins to collect in the four tanks. Each tank holds a maximum of 1,500 gallons, where it is stored until we need water somewhere in the house. (After the rain is over, the roof washer is drained by turning a valve, making it ready for the next shower.)
When we turn on a faucet, the pump kicks on and starts pulling water from the tanks. First, the water is drawn through a cotton filter to eliminate any particulates. Next, it is pulled through a carbon filter for taste. Last, it passes through a UV filter, where bacteria and viruses are killed instantly.
(Filter/UV light battery)
Quick Answers to Big Questions:
What kind of roofing material works best for collecting rainwater?
Hands-down, a metal roof is your best bet if you're collecting drinking water. If you collect off asphalt shingles, you need to filter out small particles that break down as your roof ages. If you have real wood shingles on your roof, the chemicals used to treat those shingles are a huge problem for drinking water.
How much water does a person use in a day? How does that translate to knowing how much water you need to store?
Consider all that you use water for each day: drinking, cooking, brushing teeth, showers, washing clothes, etc. In a conserving household (where you turn water off when you brush your teeth), the average person will use between 25-50 gallons a day. We estimated that each person in our family would use an average of 25 gallons per day, taking into account our composting toilet.
25 gallons/person/day x 4 = 100 gallons/household/day.
Looking at weather patterns over the past hundred years, we realized that we wanted to be able to store enough water to last our family for a two-month stretch at a time. (Two months was the longest western PA had gone without a good-size rain.)
So...100 gallons/household/day x 60 days = 6,000 gallons
Each of our four tanks holds 1,500 gallons of water, so we are able to store 6,000 gallons at full capacity.
(1,500 gallons in this tank as of this morning!)
What are options for water storage?
People have created cisterns out of many materials. Historically, stone cisterns have been very popular. Today, that is a very expensive option. More affordable, cement tanks often have an aftertaste. Ready-made tanks of metal, polypropylene and fiberglass are more affordable and easier to transport. We chose tanks of fiberglass because I happen to be very picky about the taste of my water, and fiberglass was the best option for fresh-tasting water.
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Thanks for visiting! Tomorrow: our water-related splurge!
For further reading:
American Rainwater Catchment Systems Association
Suzy Banks and Richard Heinichen, Rainwater Collection For the Mechanically Challenged (Texas: Tank Town, 2004) ISBN#: 0-9664170-6-2