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Aug 16, 2012

The Grey Water Revolution

In the last few years there has been a revolution in green building: greywater.

This movement was spearheaded by a media-savvy Oakland group called the Greywater Guerrillas. They were installing illegal greywater systems in open defiance to California's laws. What exactly is their crime? They were piping drain water from sinks and showers out to their plants.

Greywater systems filter sink, shower and laundry water (but not toilet water) through gravel, mulch or plant roots and use the resulting water for outdoor irrigation. With California suffering through yet another drought year ," the fact that this precious resource cannot be reused has been a pet peeve of environmentalists statewide.

That water could go to waste in drought-ridden California is a far greater crime than the activities of the Guerrillas. So in 2007 California passed new codes that for the first time specifically allowed the construction of greywater systems. But what at first seemed like a Robin Hood success story turned into a Kafkaesque defeat as folks realized the regulations were so burdensome that no one could navigate their regulatory maze.

With great fanfare the latest turn in the saga was reported. A demonstration green home in Berkeley, dubbed Ecohouse, is the first to get approval of a greywater system through the new code structure. Normally, getting a building permit would not be deemed newsworthy, but California is abuzz.

Today most people get fluorinated, chlorinated, sterile drinking water piped into their houses. About half that water goes straight to the plants outside in our gardens. Of the water used indoors, two thirds is used for showers, laundry, toilet flushes and bathroom sinks — all uses that do not require potable water. After use, this water is dumped down the drain where it flows to a sewer processing plant and is treated like the potentially much more dangerous water from our toilets, called blackwater. The water is processed, chemically and mechanically treated and then unceremoniously dumped into our streams, bays and oceans.

In worst-case scenarios, many sewage treatment plants regularly overflow, sending untreated blackwater into our waterways. This public health threat would be greatly diminished by the significant use of greywater.

Clearly the current system is inefficient and costly, and wasting a precious resource. Less obvious is the fact that greywater is better for plants than the sterile water we drink. The dirt, soap and skin cells we wash off our bodies provide micronutrients for plants. Recycling nutrients from our bodies back into the soil reduces the need for watershed-damaging fertilizers.

As for regulation, the state has a legitimate roll in safeguarding public heath, and officials are right to allow only greywater systems that are safe and effective. But greywater, on the household level, is just not a significant source of potential disease.

Greywater use has obvious benefits to our environment, economy and infrastructure. County and state laws have come a long way in allowing greywater systems. Now it's time to encourage them for everyone's benefit. Visit for more information.


Americans have one of the most sophisticated potable water supply systems in the world. At great expense we filter, chlorinate, fluoridate, process and endlessly test the water piped into our homes. Half of that ultra-processed water gets diverted out to landscaping. Three quarters of the water used in the home would make perfectly good landscaping water, yet it is required to be dumped down the drain by current laws.

The water that goes down the drain is all treated like raw sewage. It enters a sewage treatment plant that settles it, agitates it, aerates it, adds biological agents, and endlessly tests it for safety before throwing it away. This is expensive and wasteful, whereas using greywater from our homes to irrigate our plants would reduce consumption by half.

Local officials usually just adopt model codes, such as the California Building Code and the California Plumbing Code, for building a water use. However, since the state is woefully behind the science in greywater, local jurisdictions are wise to adopt sensible modifications to allow greywater, encouraging water savings and reducing the stress on our overburdened sewage processing facilities.

Many jurisdictions are evaluating green building codes right now. If you have a passion for green building, contact your local city council or county supervisor and express your support for enactment of a greywater model code.

- Forrest Linebarger CEO VOX Design Group Inc.