Greywater Action

Greywater Action


Guest post from Laura Allen who is a founding member of Greywater Action and has spent the past 15 years exploring low-tech, urban,sustainable water solutions. She is the lead author of the San Francisco Graywater Design Guidelines for Outdoor Irrigation, and authored The Water-Wise Home: How to Conserve and Reuse Water in Your Home and Landscape(Storey Press, 2015). 

Adapted from About Greywater Reuse

Greywater is gently used water from your bathroom sinks, showers, tubs, and washing machines. It is not water that has come into contact with feces, either from the toilet or from washing diapers.

Greywater may contain traces of dirt, food, grease, hair, and certain household cleaning products. While greywater may look “dirty,” it is a safe and even beneficial source of irrigation water in a yard. Aside from the obvious benefits of saving water (and money on your water bill), reusing your greywater keeps it out of the sewer or septic system, thereby reducing the chance that it will pollute local water bodies. Reusing greywater for irrigation reconnects urban residents and our backyard gardens to the natural water cycle.

The easiest way to use greywater is to pipe it directly outside and use it to water perennial shrubs, vines, or trees (fruit trees are nice!). In any greywater system, it is essential to use “plant friendly” products, those low in salts, boron, or chlorine bleach.

At the residential level, simple designs are often the best option. With simple systems you are not able to send greywater into an existing drip irrigation system, but rather shape your landscape to allow water to infiltrate into the soil and use larger outlets to prevent clogging.

Greywater reuse is a way to increase the productivity of sustainable backyard ecosystems that produce food, clean water, and shelter wildlife. Such systems recover valuable “waste” products–greywater, household compost, and humanure–and reconnect their human inhabitants to ecological cycles. By modeling “appropriate technologies” for food production, water, and sanitation in the industrialized world, we can replace the cultural misconception of “wastewater” with the possibility of a life-generating water culture.

Laura Allen
Greywater Action
Author: The Water-Wise Home: 
How to Conserve, Capture, and Reuse Water in Your Home and Landscape