When it does rain, the coastside gets a sizable part of it’s residential water need.
For a 24 hour portion of the Saturday January 5th rain storm i measure 2 1/4” of rain in El Granada, Ca.
Not very scientific… I simply used a straight wall drinking glass in the back yard.
But by computation I see that this rainfall totals about 1/3 of my family’s bi-monthly water usage.
Here is the numbers: 2 1/4” of rain, the roof of our house is about 2500 square feet…. that leads to….
468 cubic feet of water received on the roof, which is also 3500 gallons.
Our bi-monthly CCWD water bill sometimes dips down to 1300 cubic feet or (13 hcf in billing parlance).
I noticed as my son studied Ancient Rome in Middle School that one of the distinguishing architectural features of Roman villa construction was the villas were roofed to guide rain water to an inner courtyard and a water storage structure. An interesting precedent yes? Also, the use of lead in the plumbing has been linked with the collapse of Roman society - the leaded water resulted in falling birth rates and increased brain damage in developing Roman children.
So I penciled out a rain collection scheme. To store 3500 gallons of rain I would need 63 barrels of 55 gallons each. The barrels cost $30 each resulting in $1900 needed to store one day’s heavy rain to meet 2 to 3 weeks of careful home water consumption.
