My colleagues in water conservation suggest googling "CUWCC" (California Urban Water Conservation Council, something like that). Also, the Santa Clara Valley Water District sponsored water audits (done by third-party consultants) last year for local businesses, and a Safeway participated. My colleagues also said the city of Seattle would be a good resource to check.
Hope that helps. The above is my opinion & not necessarily my employer's opinion.
From: michelle gaither [mailto:firstname.lastname@example.org]
Sent: Wednesday, February 08, 2006 10:31 AM
Subject: Water use audits at grocery and drugstores