No green home is complete without a good program for saving our most precious resource--water. I recently wrote a post about reusing grey water (the wastewater after washing and condensation), which is a great start. Nevertheless, with grey water, we’re still pulling that water from the treatment plant--even if it is a lot less. So why not make use of the resource in a way that actually avoids using up reservoirs--going “off-grid” with as much water as we can?
Now, let’s be clear about one thing--drinking water must be treated before consumption. Thus a simple rain water collection system will not be sufficient for drinking. That said, the average American uses 100 to 250 gallons of water per day--and we know from experience that a huge part of that is not going toward food and drink.
So, rainwater harvesting can be readily (and cheaply) used for the same stuff as grey water--our gardens, toilet flushing, and potentially our domestic activities like washing. Thus we can drastically reduce our water usage, and in urban areas, utilize water that would just end up in storm drains.
Collecting Rainwater
The simplest way to collect rainwater is off your roof. Get drainpipes big enough for the amount of rain in a heavy storm, and ensure they are sloped enough to efficiently drain down to downspouts. Make sure they’re clean, checking regularly. You can then cut off down spouts above the ground, and drain them directly into closed rain barrels. In some cases, the barrels will be connected to storage tanks; make sure the storage volume you have is appropriate for the amount of rainfall you can expect. This is usually a project for the consultation and work of a certified professional.
The barrels collect the water until you’re ready to use it for your garden, or as an alternative supply for cleaning around the house and flushing toilets. In areas with hard water, this collected water can be even better for cleaning than what's coming from the reservoirs.
Tips: Let the rain after a long dry spell go to waste for a day or so, to get rid of roof contaminants like dirt and bird droppings, and make sure that the barrels are cleaned regularly.
Legal Stuff
It used to be illegal to collect rain water in some areas of the U.S., but as more and more officials wake up to the reality of climate change, this is changing. In New Mexico, for example, it’s now a requirement to build new houses with a rainwater collection system--how progressive! Ask a certified contractor in your area about the rules surrounding rainwater harvesting, as it varies state-by-state.