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Harvesting Water

Revision Date: 31 January 2009
Rebecca Pineo, Botanic Gardens Intern
Susan Barton, Extension Specialist
University of Delaware Bulletin #126

Harvesting water involves capturing rainwater, grey-water, and wastewater on your property and recycling it on site, either for irrigation or to recharge groundwater supplies. Implementing this water conservation strategy provides a myriad of environmental benefits.

What are the benefits of harvesting water on your property?

Methods of Harvesting Water on Your Property

Rain Barrels and Cisterns

[2]Water tanks stored above and/or below ground can capture rainwater from downspouts for later use.

Rain barrels and cisterns come in many styles, materials and sizes to accommodate a variety of needs. Generally, they are constructed from recycled plastic, metal, or concrete and are equipped with a fill pipe (A) (connected to a downspout), a lockable lid, and an overflow pipe with optional overflow storage. Inlet and outlet areas are screened with fine mesh to prevent debris, mosquitoes and other pests from accessing the water supply. Rain barrels placed at higher elevations can be used with a hose attachment to deliver a low-pressure water flow around the landscape. Small pumps are useful for extracting water from ground-level rain barrels or below-ground cisterns.

To protect against potential leaks, the International Building Code recommends rain barrels and cisterns be located at least 10 feet away from building foundations. If located less than 10 feet, there should be a minimum slope of 5% away from the building.

For instructions on constructing a do-it-yourself rain barrel, check out the Appoquinimink River Association’s Rain Barrel brochure, available online at http://www.apporiver.org [3], on the Projects page under “Gardening for the Environment.”

Recycling Grey-Water

Grey-water is used water from showering, bathing, washing dishes, laundry, aquariums, etc. It does not include wastewater from toilets or latrines.

Sub-surface irrigation through perforated pipes or buried soaker hoses is the safest way to use untreated grey-water. In many cases, surface irrigation is also appropriate, as percolation through healthy topsoil will remove most impurities. No matter how you use grey-water, it is important to use it completely on site. Any unused captured grey-water should be disposed of through your normal septic system, not dumped down storm drains.

There are many grey-water recycling systems or do-it-yourself kits on the market that involve re-routing your drainage pipes, with opportunities for on-site treatment. A simple way to capture a portion of your grey-water is to place a bucket in your showers and sinks, using it when full to irrigate house or landscape plants.

Some localities have ordinances regarding harvesting and use of grey-water, so check with your local government before investing in grey-water recycling systems. Research on safety and health concerns is ongoing, so play it safe by adhering to the following guidelines.

Guidelines for Grey-Water Use


Rain Gardens

Rain gardens, sometimes called bio-retention areas, are shallow depressions in the landscape that capture stormwater and allow it to gradually percolate into the soil. Planted with moisture- loving plants that help filter out pollutants, rain gardens provide an attractive way to reduce the impact of stormwater on the environment.

Green Roofs

A green roof is a specially-engineered rooftop that supports plant life and captures rainwater before it runs off. Green roofs have been utilized in Europe for 30 years and are quickly gaining popularity in the United States.

Additional Resources

City of Tucson Water Harvesting Guidance Manual

http://dot.ci.tucson.az.us/stormwater/downloads/2006WaterHarvesting.pdf [4]

Greywater Central

http://www.greywater.net [5]

Rain Barrels – Appoquinimink River Association

http://www.apporiver.org/RainBarrelBrochure_Final.pdf [6]

Rainscapes: Rain Barrel Assembly

http://www.montgomerycountymd.gov/Content/DEP/Rainscapes/pdf/barrel.pdf [7]

Rainwater Harvesting for Drylands and Beyond: Rainwater-Harvesting Info/Resources

http://www.harvestingrainwater.com/rainwater-harvesting-inforesources [8]

Urban Design Tools: Rain Barrels and Cisterns

http://www.lid-stormwater.net/raincist_specs.htm [9]

Water for Life: Grey Water

http://www.deus.nsw.gov.au/Water/Greywater/greywater.asp [10]


Appoquinimink River Association. (Unknown date). Rain Barrels. Available online from http://www.apporiver.org/RainBarrelBrochure_Final.pdf [6]

Ford, Dave, Scott Telford, and Kevin McOsker. (2007). Highlights of the General Architectural, Structural, and & Grading Provisions. Retrieved November 9, 2008 from http://dsnet.co.clark.nv.us/dsweb/presentations/2006_IBC_Presentation.pdf [11]

Ludwig, Art. Oasis Design: Greywater Central. (2008). Retrieved November 9, 2008 from http://www.greywater.net [5]

New South Wales Government Department of Energy, Utilities and Sustainability. (2006). Water for Life: Grey Water.Retrieved November 9, 2008 from http://www.deus.nsw.gov.au/Water/Greywater/greywater.asp [10]

Phillips, Ann Audrey (editor). (2005). City of Tucson Water Harvesting Guidance Manual. Retrieved November 8, 2008, from http://dot.ci.tucson.az.us/stormwater/downloads/2006WaterHarvesting.pdf [4]