Residential greywater systems are now legal in California, and most modest residential installations don’t ever require a permit. But exactly how the changed rules are being implemented remains a little murky.

Sonoma County PRMD deputy director Duane Starnes explains why diverting laundry water outflow to a greywater reservoir also requires some additional changes to the household’s existing plumbing, such as the diversion valve shown at right.

Art Ludwig, a long-time advocate for legalizing greywater systems, says the state’s new rules allowing them carry an almost symbolic significance that extends well beyond mere plumbing.

Ludwig's Oasis Design website has detailed and illustrated instructions on how to install a "laundry to landscape" greywater system.

The Bay Area's Greywater Guerrillas are another online resource.