Rainwater Harvesting

Did you know that a ½ inch of rain that falls on the roof of a 1,500-square-foot home can equal 500 gallons of water? By capturing this rainwater instead of letting it run into the street, you will help to conserve our precious water resources and save money irrigating the plants in your yard.

To assess your potential for harvesting water, it is helpful to spend some time outside observing what happens after a rain. Where is this water that is shed off the roof going? If it is falling onto the driveway instead of a planting bed, it could easily be redirected.

Rainwater can be harvested in different ways. One of the easiest to implement is called passive techniques, which directs water right into the soil for immediate beneficial use. This can be done by constructing basins, berms, swales, or shallow depressions. These contours in the landscape can be constructed before you design and install or after the fact. Make sure standing water disappears within a day and that you keep any water storage away from the foundation of buildings.

Another way to harvest rainwater is through catchments such as rain barrels or tanks. These active techniques direct water to these catchments through gutters on the roof of your home.

Passive Water Harvesting Techniques Active Water Harvesting Techniques
  • Infiltration basin
  • Berm n’ Basins
  • French Drain
  • Swale
  • Tanks
  • Cisterns
  • Barrels

Drawing a map of your property will help you assess your rainwater harvesting potential. Be sure to indicate with arrows the direction water flows off your roof and mark the high and low points of your property. Make note of where water tends to accumulate. Show the direction of water from any slopes in the yard. If you have a large slope, you can use berms to slow water down enough to soak into the soil.

Rainwater Harvesting Resources


Prehistoric Water Utilization and Technology in Arizona, by Foster, Michael S., Arizona State Parks, State Historic Preservation Office; Bureau of Reclamation, Phoenix Area Office

Texas Guide to Rainwater Harvesting, by Wendy Price Todd and Gail Vittori, Texas Water Development Board in Cooperation with the Center for Maximum Potential Building Systems, Second Edition, 1997; Austin, Texas.