Components of a Rainwater Harvesting System

  • Capturing the rainwater
  • Storing
  • Filtering
  • Emergency use
  • Distribution for irrigation and/or designated use

Catchment Surface:

Most roof surfaces are acceptable. Roofs with smooth surfaces, like metal and concrete tile, are best for durability and rainwater quality. For a tar and gravel roof or cedar shingle roof impregnated with fire retardant, we typically recommend other roofing solutions for a rainwater system. Solar panels are also ideal catchment surfaces and are increasingly integrated into rainwater systems.

Gutters and Downspouts:

Gutters catch rainwater that is then diverted into downspouts where rain can be channeled into storage tanks. We recommend pre-filtration components to initially remove large particulates.

Pre-filtration Components:

Leaf Screens, First flush diverters or roof washers are pre-filtration components to ensure the storage of the highest quality water. First flush diverters and roof washers reduce accumulated small particles from entering the storage tank.


Above Ground – There are many different size and shape tanks for above ground use. The most common types of storage tanks are: polyethylene, corrugated metal, concrete and Ferro cement and a wide variety of rain barrels.

Underground – There are also solutions to storing water below ground. Underground tanks or modular units can be linked together to serve as a void space to collect and store water. Used most often if space is limited or if there is a visibility issue.


There are energy efficient and easy-to-use pumps on the market perfect for rainwater applications. Commonly, when irrigation is desired — a pump can be used to transfer and pressurize the water. Gravity flow usually does not provide adequate pressure for most irrigation systems unless there is a large elevational difference.

Treatment and Purification:

Typically rainwater is filtered one more time before the point of use as a precaution to ensure proper irrigation system function.

View successful rainwater harvesting projects