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Public Works will re-open our front counter to the public on July 6 and start providing some modified services.  Our hours will be 8 – 5, with closure from 12 – 1:30 for sanitation. Masks are mandatory in our building, and we ask that you adhere to physical distancing protocol. We will have limited services at our front counter and will not be accepting drop in meetings.  Please contact 805-781-5252 to make an appointment with staff.  Bus passes can be purchased at the Kiosk on the corner of Osos and Palm or by phone via Follow us on Twitter @SLOCountyPWD for the latest updates.

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Water Quality Lab

Manager - Faith Zenker

The Department of Public Works Water Quality Lab (WQL) was founded in 1969 with the building of the Lopez Dam and the subsequent startup of the Lopez Water Treatment Plant. The WQL eventually expanded to provide laboratory services for all the Public Works operated water and wastewater systems. The WQL is certified by the State of California's Environmental Laboratory Accreditation Program (ELAP). To remain certified by the State, the lab is required to annually demonstrate capability by analyzing unknowns for each constituent.

A list of certified labs can be found at the State Water Resources Control Board.

In addition to analytical work, the WQL also provides sampling, compliance reporting, watershed monitoring and technical support services for all of our systems.

Please contact us at (805) 781-5111

Send requests by mail to:
County of San Luis Obispo
Department of Public Works - WQL
County Government Center, Room 206
San Luis Obispo, CA 93408

Related Services

Drinking Water Source Assessments
Invasive Mussels
Watershed Sanitary Surveys
Water Quality Reports

Related Forms & Documents

NPDES Annual Notification
NPDES Aquatic Weed Control Plan
Lake Nacimiento Water Quality Report
Zone 3 (Lopez Pipeline) Water Quality Report

Contact Public Works via web form, email, or call us at (805) 781-5252.