This one page is an introduction to greywater and its use as a water recovery method. It was written by Monterey Greywater Group / Guild

This is a very extensive discussion of greywater, what it is and how to use it, with very informative graphic - a good how to paper.

A compilation of grey water laws , suggested improvements to gray water regulations, legality & greywater policy considerations, sample permits, public health considerations, studies, etc.

"Create an Oasis", a book description. The book describes how to quickly and easily choose, build, and use a simple greywater system. Some can be completed in an afternoon for under $30.
               (The two links, above, show a bit of how and what Oasis Design  does.)

The Tidal Wetland Living Machine® at Esalen Institute takes wastewater from the institute's laundry and lodging facilities and turns it in to clean water.  The cleansed water then gets reused for irrigation of the extensive gardens and returned directly to the re-charge the aquifer.
               (This installation was built by Worrell Water Technologies'.)

The form from Monterey County Health Department for APPLICATION FOR GRAYWATER IRRIGATION SYSTEM PERMIT is available, in PDF format.

Links to the 2 referenced codes, on the Permit form, are below.

Click on this link Monterey County Code 15.20 - Sewage Disposal, and then find, in the left hand column and click on "Title 15 - PUBLIC SERVICES" . In the list in the new window on the right click on "Chapter 15.20 - SEWAGE DISPOSAL".
and
The 2010 draft of the California Plumbing Code Chapter 16A-1 as a PDF document.