Home Design & Build -- Cisterns with Bypass/First Rain Diverters!!

Home Design & Build -- Cisterns with Bypass/First Rain Diverters!!

In my business, I spend much of my time chatting with islanders, and reminding them of the basic techniques of being a good "rainwater farmer": watching the skies, using simply devised, easy to operate first rain diverters, maintaining treatment systems, and avoiding the plague of tree pollen season. It doesn't take much -- 10 -20 minutes every month for a homeowner to keep their systems operating effectively.


I hope that many of the home builders/designers will take heed too. I visit many homes that have cistern collection pipes hard-plumbed in, so that diverters and bypasses have to be scabbed on as an afterthought. And once a few heavy pollen seasons and decomposing debris build-up in the cisterns, water quality is very poor. It's a shame for beautiful homes to have what amounts to old pond water for their household supply.

If you are in the process of getting a home designed with a cistern built-in to the foundation, be sure to ask your builder to incorporate: 

1. Roof collection rain diverters/bpyass pipes -- so that 10 gallons of "first rain" per every 1,000 sq ft of rooftop collection surface is able to be diverted from your cistern;
2.  Incorporate chamber design into your concrete cistern -- so that one chamber at a time can be isolated, drawn down and cleaned periodically, while still maintaining a supply of water to the house.
3. If separated chamber design is not practical, construct  a sump area or collection well into the cistern so that the rainwater inlet filling  the cistern is partially dammed, calmed and isolated from the rest of the reservoir. A weighted half-height rain barrel would do. That way, rainwater falls into the barrel first (along with debris) before spilling over the submerged edges to fill the cistern