For more information about water quality, or for any questions relating to your drinking water, please contact 781-7215

Water Quality

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Water Quality/Consumer Confidence Reports

We are once again proud to present our annual water quality report covering all testing performed between January 1, and December 31, 2017.  Over the years we have dedicated ourselves to producing drinking water that meets all state and federal standards.  We continually strive to adopt new methods for delivering the best quality drinking water to you.  As new challenges to drinking water safety emerge, we remain vigilant in meeting the goals of source water protection, water conservation, and community education while continuing to serve the needs of all our water users. 

2018 Annual Water Quality Report

Please remember that we are always available to assist you should you ever have any questions or concerns about your water.

Drinking Water Fluoridation

The city adds fluoride to the treated water produced by the water treatment plant to help prevent dental caries in consumers.  Some limited areas along Los Osos Valley Road receive a blend of surface water and ground water that may have a lower fluoride residual.  State regulations require the fluoride levels in the treated water be maintained within a range of 0.6 - 1.2 ppm with an optimum dose of 0.7 ppm.  Our monitoring showed that the fluoride levels in the treated water ranged from 0.1 - 0.9 with an average of 0.62 ppm.  Information about fluoridation, oral health, and current issues is available from  

Important Health Information

Some people may be more vulnerable to contaminations in drinking water than the general population.  Immunocompromised persons such as persons with cancer undergoing chemotherapy, persons who have undergone organ transplants, people with HIV/AIDS or other immune system disorders, some elderly, and infants may be particularly at risk from infections.  These people should seek advice about drinking water from their health care providers.  The U.S. EPA/CDC (Centers for Disease Control and Prevention) guidelines on appropriate means to lessen the risk of infection by Cryptosporidium and other microbial contaminants are available from the Safe Water Drinking Hotline at (800) 426-4791 or

Source Water Assessment

An assessment of the drinking water sources for the City of San Luis Obispo was conducted March 2014.  The surface water sources, Salinas Reservoir and Whale Rock Reservoir, are considered most vulnerable to the following activities although no associated contaminants have been detected: cattle grazing and historic mining activities.  To request a summary of the assessment, contact us at 781-7215.

Lead in Home Plumbing

If present, elevated levels of lead can cause serious health problems, especially for pregnant women and young children.  Lead in drinking water is primarily from materials and components associated with service lines and home plumbing.  We are responsible for providing high-quality drinking water but cannot control the variety of materials used in plumbing components.  When your water has been sitting for several hours, you can minimize the potential for lead exposure by flushing your tap for 30 seconds to 2 minutes before using water for drinking and cooking.  If you are concerned about lead in your water, you may wish to have your water tested.  Information on lead in drinking water, testing methods, and steps you can take to minimize exposure is available from the Safe Water Drinking Hotline or at

Water Quality Reports

2016 Annual Water Quality Report

2015 Annual Water Quality Report

2014 Annual Water Quality Report

2013 Annual Water Quality Report

2012 Annual Water Quality Report

2011 Annual Water Quality Report

2010 Annual Water Quality Report

2009 Annual Water Quality Report

2008 Annual Water Quality Report