Wholly H2o - California's Integrated Water Reuse Management Center

You can double the benefit of your stored rainwater by using it indoors and then reusing the resulting graywater for toilet flushing or irrigation! An architect, landscape designer, permaculturist, or other professional with experience in RWH can design the most appropriate and cost-effective system for your situation. See our Product and Service Provider listings to find qualified professionals in your area.

Even a small collection surface in a very low rainfall area can capture significant amounts of rainwater. Given our long, dry California summers, your system’s configuration will mostly be determined by how much storage capacity you have space for and can afford.

Some general concepts to consider for every project:

• The earlier RWH is incorporated into a new building design process, the more efficient and cost-effective it will be.
• The largest and typically the costliest feature of your system will be the storage tank (often called cistern).
• Storage tanks can be installed above or below ground.
• Storage located high on the building or the site saves energy and costs (no pumps = zero energy use).
• Elevated storage requires structural and seismic engineering.
• Above ground storage tanks can serve additional beneficial purposes as shade or privacy structures, and as heat sinks.
• Tanks and pipes must be protected from freezing temperatures (underground or indoors)
• Underground tanks must be anchored to keep from floating to the surface when empty.
• Try to use gravity as much as possible for the movement of water in your system.
• Plumbing, backflow and airgaps

Design Guidelines/Step-by-step directions:

• http://www.twdb.state.tx.us/publications/reports/RainwaterHarvestingManual_3rdedition.pdf
• http://www.portlandonline.com/shared/cfm/image.cfm?id=182095
• http://www.rainharvesting.com.au/create_a_complete_system.asp
• http://www.bae.ncsu.edu/stormwater/PublicationFiles/WaterHarvestHome2008.pdf

Case studies:

• http://watersprout.org/water_systems/rainwater_catchment/parker.html
• http://watersprout.org/water_systems/rainwater_catchment/vanelli.html
• http://watersprout.org/water_systems/rainwater_catchment/meckler.html
• http://www.homedepotfoundation.org/pdfs/reach_3.pdf
• http://www.twdb.state.tx.us/iwt/rainwater/award0804.html