As a native of Santa Barbara, and having lived through several droughts, I have seen many graywater systems rigged up and used for irrigating and watering plants. Up until now, these systems have not been legal. Be sure to research what types of soaps and detergents can be used if you are looking to implement this water saving system.
What is Greywater?
According to Wikipedia: Greywater, also known as sullage, is non-industrial wastewater generated from domestic processes such as dish washing, laundry and bathing. Greywater comprises 50-80% of residential wastewater. Greywater comprises wastewater generated from all of the house's sanitation equipment except for the septic tank (water from toilets is blackwater, or sewage).
In recent years, concerns over dwindling reserves of groundwater and overloaded or costly sewage treatment plants have generated much interest in the reuse or recycling of greywater, both domestically and for use in commercial irrigation. However, concerns over potential health and environmental risks mean that many jurisdictions demand such intensive treatment systems for legal reuse of greywater that the commercial cost is higher than for fresh water. Despite these obstacles, greywater is often reused for irrigation, illegally or not. In droughtzones or areas hit by hose pipe bans (irrigation restrictions), greywater can be harvested informally by manual bucketing.
The article below describes how that has now changed, which, in my opinion is great news.
In Historic Move, California Building Standards Commission Green Visionaries Approve New Graywater Standard --
July 31st, 2009
A collision of world views was in full evidence at the California Building Standards Commission hearing yesterday on HCDs proposed new graywater standards.
Highly qualified stakeholders spoke passionately for and against the adoption of the new standards as the hearing roller-coastered dramatically to it's conclusion.
The commissioners are to be congratulated for their leadership. It is always more work to set up a new system than to fit into an existing one.
It would be a lot easier to stand aside as legal buildings continue waste resources and pollute the environment. However, in the face of deeply entrenched, powerful opposition, the commission is rising to the challenge of revising all of California's building codes to allow/ require better building systems...besides its emergency approval of the new graywater standards yesterday, the BSC is also revising California's Green Building Standards to include many new mandatory and voluntary measures to reduce negative impacts and increase positive impacts of California buildings.
Dawn of a new era: "On August 4th, 2009, California can legally install simple laundry and single fixture systems without a permit. For the first time, licensed professionals can legally help with the 1.7 million existing graywater systems in the state. " --Art Ludwig, graywater researcher and educator.
For more information visit: www.oasisdesign.net/greywater/press