Ok. so you want to know about rain water harvesting? Alrighty then, for the purposes of feasible storage and re-use, we’ll focus on above ground systems for now…
First you need a catchment area. For most of us, the best option is our roof. It doesn’t take a big roof *(see examples below)* The best material? Metal, but shingles will do for watering plants.
Second: gutters and downspouts. These act as a funnel to concentrate the catchment area runoff to fill a water storage container, such as a rain barrel or bench.
Next, you need to adapt your downspouts to fill your rainwater collection container. There are a variety of good products out there to do this; they are called “rain diverters.” Saving Rain, LLC makes the best one of these we have found to date.
roof runoff examples: amounts of runoff from 1″ rainfall on…
- 8’x16′ garden shed with 1′ overhang = 112 gallons
- a 2-car garage, at 24’x24′ with a 2′ overhang = 488 gallons
- a 2,500 sq.ft. ranch home = 1,558 gallons, all from just 1″ of rainfall
so the basic calculation is: (L x W (in feet) of your roof) x .623 …yes, there are coefficients that can be considered, but this is basics. that’ll do.
In ‘Advanced Rainwater Harvesting‘ you will find descriptions explaining a more advanced integrated rainwater harvesting system.
click to continue to Rainwater Basics 2