Water Harvesting: Active Collection for Later Use

Water harvesting for later use involves collecting rainwater in a tank of some kind. Tanks can be as simple as a sturdy garbage can under a downspout or as complex as a large underground tank and pump.

Why Collect Water for Later Use?

  • Can reduce water bills
  • Saves a valuable resource
  • Rainwater is free of salts and other minerals or chemicals that may be harmful to plants
  • Reduces pollutants to area streams and rivers by keeping water on site and off impervious paved areas
Rainwater storage tank outside adobe house
Rainwater storage tank made from culvert pipe in Arizona. Photo credit: Susan Buffler in Landscape Water Conservation Flickr CC BY-NC-SA 2.0

Tips for Collecting Water for Later Use

  • Know how much water¬†is going to come off of the roof or other surface. This will determine tank size
  • Provide an overflow outlet or link to another tank
  • Use a filter to collect debris from roof runoff
  • Use a purification system if using for drinking water
  • Metal roofs work best
  • Check local ordinances. Rainwater collection for storage and reuse is restricted or illegal in certain states, counties and cities
  • Use opaque dark colored tanks to reduce algae growth
  • Use HDPE pipe for above ground tanks. Avoid PVC pipe which degrades in sunlight

Additional Resources:

An Introduction to Green Infrastructure Practices
Regulations and Statutes


Colorado – Rainwater Collection
Nevada РMake Each Drop Count: Harvest Water for the Landscape
Washington – Homeowner Practices for Managing Rain


Rain Barrels Part I: How to Build a Rain Barrel
Rain Barrels Part II: How to Build a Rain Barrel


Alabama – Rainwater Harvesting for Irrigation Water


Arizona – Rainwater Harvesting for Drylands and Beyond
Texas – Rainwater Harvesting