Rainwater Harvesting

1. Roof flush - dump first X gallons into a tank (slowly drains into gutter) that overflows into staging
   1. Optional float valve decreases cross contamination


2. Staging - holding tank to give pump a chance to run in cycles


3. Storage - Single point of piping attachment - fill and drain are same plug on bottom + screened vent on top
   1. Overflow and level read are the same standpipe by one of the tanks

Alternatively, instead of having staging downhill and pumping to storage uphill, have the storage downhill (even underground) and pump water as it's used. One or more irrigation supply tanks could take water pumped up from storage, using gravity to feed the drip lines. Overflow from these tanks could wet the roof, providing many additional benefits:

1. Wetting the roof means that overflow (outside of evaporation) ends back into storage, closing the loop.


2. The evaporation would be a possible alternative way to cool the house and surrounding area.


3. Left running continuously (or until there was no more water in storage) provides some protection against external fires.

References:

1. An Oregon household built a full Rainwater Harvesting and Purification System that provided water to the whole house.


2. Harvest H2O has a number of articles
   
   
   1. A comparison of storage systems shows the pros and cons of different containers.
   
   
   2. A floating filter intake ensures you get the best of the water in the storage tank.
   
   

14-Apr-2009

Another late-nite idea: Site permitting, the downhill cistern can be hidden in an underground shed. Appropriate roofing allows for a garden with shallow roots (flowers, etc). The uphill wall already needs drainage, which could share plumbing with the overflow lines.

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