If the average annual rainfall is approx 35" and my home floor space is approx 30' x 20'......?

Question

What would be the volume of rainwater that i could be harvesting? Im trying to work out how many barrels i need to set up to store all the rain water in.

Only people that know what they are talking about answer please. Thank you.

Answer 1

yes about 5 cubic metres, i had to convert it to metric to work out too. but not all that is falling at one time, if you say 3/5 of it in winter and you want to store that, 3  cubic m would be fine. that is about 15 ordinary water butts.

you can get second hand 'IBC's (intermediate bulk containers) which are one cubic metre each, they are used in industry to carry liquids and are like a big cube of plastic in a metal frame. they stack up too.

like this;

http://www.smithsofthedean.co.uk/Recycle...

but you will have to search for a supplier in your locality.

Answer 2

Where are you?  Have you got a full system to prevent evaporation?  Are your barrels above or below ground?  More info please.

Answer 3

30 feet by 20 feet is 9.23 m by 6.15 m so you have 56.8 square metres.  Every 100 cm of rain gives you 5.68 cubic metres of water for that area.  So 35 inches is 88.9 cms which gives you just over 5 cubic metres which is not a lot.  35 inches of annual rainfall is very low and you will not be able to harvest enough water for all your needs with such a small catchment area.  If you have 100 square metres of building and a rainfall of 2000 mm per year then you would get a harvest of 200 cubic metres which is getting close to meeting the needs of a small household if economic with water.

Answer 4

I'd say about 13,100 gallons.

Answer 5

30'X20'=360X240=86,400 square inches

86,400X35=3,024,000 cubic inches= 1750 cubic feetX8gallons per cubic foot = 14000 gallons

you'd need about 280 50 gallon barrels to store it all.   You'd most likely be using some of that water throughout the year, so only half that many at the most if you don't get your rain all at once like we do in the northwest US.