Graywater for Gardeners

By Gail Fanning

The State of California adopted regulations that allow us to legally, without permits, re-use our graywater for landscape irrigation! This is a HUGE step forward in reasonable water use policy by the State, and will go a long way toward conserving our limited water resources, while maintaining fruitful and beautiful gardens.

What is graywater (or greywater), you ask? Water from tubs, showers, sinks, and clothes washers is termed graywater: this is lightly used water that is safe to re-use in the landscape, with some common sense precautions. Every load of the washing machine uses about 30 gallons of water, and each shower uses 10 to 30 gallons! That’s a lot of water that can be used to water your fruit trees, berries, grapes, as well as most ornamental plants!

A couple notes of caution: acid-loving plants like rhododendrons and citrus will not enjoy the alkaline content of graywater. For health and safety, graywater should never be applied to the edible parts of plants: i.e., lettuce, spinach, root vegetables, etc.

Some of the basic requirements for a safe and legal graywater use are:

1) keep the discharge on your own land,

2) do not allow ponding or run-off,

3) avoid direct contact between people, pets, and graywater, and

4) any above-ground release of graywater must be covered by 2” of mulch. Naturally, you will also want to evaluate the types of soaps, shampoos, etc. that you are putting into your graywater in order to keep everything biodegradable. Bleach or boron in graywater will kill your plants!

So, how to put together your own graywater system? First, check out the State regulations at www.bsc.ca.gov (see approved changes: HCD-EF 01/09 – Emergency Standards pertaining to Graywater for Residential Application: see section 1603A.1.1 for clothes washer system and/or single fixture system requirements). Then, check out these websites for some excellent information and suggestions on system construction: oclandscape.com/ocblog, oasisdesign.net and greywateraction.org. A couple great reference books are Graywater Use in the Landscape, by Robert Kourik, and Create an Oasis with Graywater, by Art Ludwig.

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