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…

Steel Roof

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.

Hang in there...

Hang in there…

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