Rainwater harvesting amount per season??

Question

For those who know or have experience with a large cistern for gathering rainwater. How many gallons do you end up getting during the average year or the average rainy season?

I would like some info since this will let me know what the limits for using gathered rainwater are. If its plentiful enough for everyday household use without too much conserving, and how many people it can support.

I guess amount of rainfall depends on your area. I'm curious to know what the amount is for you area, especially if you live in California, but any area in general.

Answer 1

i know of a housewith about 18000 sq foot of roof in the calif desert that has a 10.000 gal cistern.

most years the rain would fill it.

this let the owners just haul water for drinking and food preparation.

the water from the shower and sink was sent out to water the trees and grass.

about 10 years ago i designed a solar powered distillation system for them so they could use a brackish water spring about a 1/4 mile from the house for drinking water.

or use the cistern water after it had been distilled

in most cases you get 1 inch of water in a 1 sq foot container

per sq foot of roof collector per inch of rain.

so you want to find the sq footage of your roof and the annual average rain fall for your area.

and build your cistern for it, this is for a desert area.

if you live in a area that has rain throughout the year you can get by with a lot smaller cistern.

if you live in a high fire area i would build it larger and rig it with a gas powered fire pump and have fire hose as it would be good for fire protection too.

Answer 2

Per adult for one year basic foods  or water for home storage.( i believe this is for drinking purposes only.)

Water ( 2 weeks) 14 gallons

for emergency reserve use only

approx 364 gallons of water per person for one year. Drinking only.

Answer 3

I put in a 5000 gallon koi pond in my backyard 4 years ago.  I just put in a rain collection system last year to help with supplying water for the pond and for watering trees and shrubs that i put in at the same time as the pond.  My collector only holds 120 gallons.  I have found that with a half inch of rain my system fills up from empty.  I live in Atlanta GA and we are in a horrible drought but I have found that I would be able to water my trees and shrubs along with filling water to my pond.  The cistern has worked for centuries and can continue to be a great asset if managed properly.

Answer 4

During 7 months 60 cubic metres of water was collected in Wales at Greenwood Park. The following article charts the success of its rainwater harvesting system.

http://greenfinder.co.uk/articles/succes...

The U.K had a really wet summer so this is probably more than your average 7 months in the U.K.

Answer 5

How many gallons you end up with in an average year depends on the square footage of the area you are using for collection, the amount of rainfall you receive in your area, and the size of the cistern(s) you have for storage.

Every inch of rain on a 1000 s.f. of roof surface generates 623 gallons of water. So to answer your question, you need to find out what the average yearly rainfall is for your area (in inches), the square footage of the roof, and the size of your cistern(s).

For example, here in Atlanta we receive an average of 50 inches per year of rainfall. If you had a house with a footprint of 40' X 50' you know you have 2000 s.f. of roof area. Therefore, in Atlanta, you could collect 62,300 gallons in an average year (50 X 623 X 2) or 5,192 gallons in an average month. Of course, you would need cisterns large enough to store that, or you could store less and have the rest of the water overflow to a drain.