STANFORD UNIVERSITY SCHOOL OF EARTH SCIENCES - EARTH SYSTEMS PROGRAM

Sustainable Choices

Explore Gray Water Use & Rainwater Capture

Simplicity:
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Carbon Impact:
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Money Savings:
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Health Helper:
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Overview
In some sense, all water can be considered recycled, through the endless process of precipitation and evaporation that carries water through our rivers, lakes, oceans, and atmosphere. Gray water is defined as recycled water that has been used for some other purpose first—namely in your shower, sink, or washing machine. Rather than using water once and then sending it down the drain, it is possible to re-use water for secondary applications such as toilet flushing or yard irrigation. Not all local governments allow the use of gray water. Consult with your local officials to learn what steps you can take to reduce your water intake.

Tips & Tricks
Learn your local gray water codes. Some municipalities do not currently allow reuse of gray water. Contact you local officials to learn the codes. If they don’t allow reuse of gray water, encourage them to change the code.

Web & Print Resources
Gray water—general information:
www.deus.nsw.gov.au
www.graywater.net
www.greywaterguerrillas.com

Rainwater harvesting—general information:
rainwaterharvesting.tamu.edu/
www.harvesth2o.com
www.rainwaterharvesting.org

Rainfall calculator:
ga.water.usgs.gov

Fun Facts

Gray water reuse may not be permitted by your local or county building codes.

One inch of rain collected over 1 square yard yields 4.7 gallons of water. Source