This rainwater harvesting (RWH) system, with an above-ground, 7,500 gallon (usable) poured-concrete cistern, used for both potable and nonpotable purposes, was designed and constructed in 2001 as an integral part of a new single-family home in Key Largo, Florida. Rain is collected from a 1,700 square-foot white Galvalume roof and gathered in six-inch copper gutters with spash shields at roof valleys for occasional heavy downpours. Copper plumbing is used throughout the house as well. Read full article>>
Question and Answer Session with John
John, first thank you for publishing the article on your home system. It is a great reference for those interested in following in your footsteps and living on rainwater and solar.
- One of the questions, that I have and I am sure many of the readers will have is - why? Cisterns were always in the Keys, so it was a natural to build when we were building our new home.
- Was 7,500 big enough? No, it is not big enough. Budget and space prevented us from putting in a bigger one. I have never met anyone that has a cistern too large. Would have liked to go at least 50% larger.
- Why concrete? The house is made of concrete and it is part of the house structure. Also it neutralizes acidity from rain and lastly it is widely available in our area.
- Why an 8" cistern wall? That is what the engineer advised.
- Who designed the system? I did. I am ARCSA Accredited.
- What is a rubber "dam" gasket? It is a piece of rubber about 1/2" thick and about 8" wide comes in a roll. It is put between the floor and wall to prevent any leakage. Half of it is put in the base around the edges when it is poured and the other half is put into the wall when it is poured.
- Do you use greywater? No, I wish we did. Regulatory barriers were a big issue in building green. Greywater would have been another barrier and we did not have the time.
- If you would to do it again, what would you do differently? I would have smaller downspouts, design some way to move water between sides of the tank, consider using a floating extractor, a low level cut of switch to prevent the pump from burning out and re-analyze newer filtration methods.
If you have any questions, please submit and John will answer them to the best of ability.