All water is not the same

Issue Date: July 9, 2008

All recycled water is not created equal. Whether it is used to fight fires, wash clothes or help farmers feed the world, recycled water comes in many forms and there are many ways to define it.

The California Department of Water Resources provides the following definitions:

  • Recycled water is highly treated wastewater from sources such as domestic sewage, industrial wastewater and storm water runoff. It ranges in treatment levels from gray water to tertiary treated, depending on the intended use of the reclaimed water.
  • Gray water is untreated, non-disinfected wastewater that has not come into contact with toilet waste. Gray water includes wastewater from residential showers, bathtubs, bathroom sinks and washing machines, which may be used in landscapes with an on-site collection system and must employ a subsurface irrigation method.
  • Tertiary treated water means that the water has been through three levels of treatment including filtration and disinfection. Tertiary treated recycled water can be used for landscape, agricultural irrigation, car washing, fishponds, firefighting and groundwater recharge and in fountains and recreational lakes where swimming is allowed.

Although the use of recycled water is catching on in both urban and rural communities, agriculture remains the top user of recycled water in California, according to the Department of Water Resources.

Redwood City's Public Works Services Department provides a handful of examples of the many ways communities are tapping into this valuable commodity. For these examples, go to

For more information about recycled water, go to

Permission for use is granted, however, credit must be made to the California Farm Bureau Federation when reprinting this item.