Rainwater harvesting

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Rain is a renewable, free source of fresh water. Harvested rainwater can be used for a variety of purposes, including irrigating lawns and gardens.

Passive Rainwater Catchment and Rain Gardens

Passive rainwater catchment, also referred to as the watershed approach to landscaping, utilizes berms, basins, and dry creeks to capture rainwater in the landscape. As a mini-watershed, with high points draining to low points, your yard will sequester atmospheric carbon, prevent water and air pollution, build healthy soil, and attract essential life into the garden.

Learn more about the watershed approach by downloading the free California Watershed Approach to Landscape Design booklet.

Rain Barrels

Rain barrels are for collecting rainwater from roofs and gutters. To get started follow the steps below:

Step 1: Learn about your roof and approximate rainwater catchment volume

  • Consider roofing material. While any material is usually acceptable, asphalt shingles may leach toxins and should not be used to collect water for vegetable gardens. 
  • Find the roof square footage. Multiply length by width, and multiply the results by .56 to get the number of gallons per inch of rain.
  • Multiply the number of gallons you just found by your area's average inches of rainfall.

Step 2: Purchase equipment

Many hardware stores carry rainwater catchment kits that can be purchased and easily installed. If you choose to create your own system, the best barrels will:

  • Not leach toxic materials.
  • Have thick walls that can withstand different temperatures.
  • Be opaque to inhibit algae growth.
  • Be securely covered to prevent children and pets from falling inside.
  • Be screened to keep out debris.
  • Be accessible for cleaning.

Step 3: Position the barrel

The barrel should be located in a safe, stable spot to prevent tipping and discourage animals and children from playing in or around it. If the barrel has an outflow valve, it can be placed on cement blocks to make water collection easier. As an added precaution, a rope or chain can be used to secure the barrel to the side of a house or shed.

Step 4: Collect rainwater and maintain the system

Both rain gutters and the water catchment system should be inspected and cleaned at least twice a year. To maintain and prolong the life of your rain barrel, you should:

  • Inspect the inside of the barrel for cracks and algae.
  • Clean the inside of the barrel with vinegar and water.
  • Replace worn parts or install patches on cracks.
  • Disconnect from the down spout if below freezing temperatures persist.
  • Only store rainwater in the barrel.

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