Oak Shores Wastewater Treatment Facility Upgrade

The San Luis Obispo County Department of Public Works has completed a Final Supplemental Environmental Impact Report (SEIR) for this project. The project includes making the following improvements to the existing Oak Shores wastewater treatment facility:

  1. Increase system capacity to serve an additional 285 residential units (total 1,197 units);
  2. Retrofit the existing treatment plant to provide nitrogen removal in the treated effluent;
  3. Increase the average daily flow capacity during the peak month by approximately 94,000 gallons per day to a maximum of 194,000 gallons per day);
  4. Add sludge-drying beds;
  5. Add spray field disposal capacity at the Gregg Ranch disposal site; and,
  6. Make collection system improvements to convey wastewater from Phases II through VI of Tract 2162 directly to the treatment plant.


The Final SEIR focuses on the following issues: aesthetics, biological resources, cultural resources, air quality, and land use. The Draft SEIR was released for public review and comment between May 18, 2018 and July 3, 2018. The District received a total of 12 comments on the Draft SEIR. A response to each comment received on the Draft SEIR was prepared, and all responses are included in the Final SEIR. The SEIR State Clearinghouse Number is SCH2017111024. The Final SEIR and related project documents can be accessed to the left.

The County will conduct a public hearing on the adequacy of the Final SEIR as follows:


Hearing Date:                    September 18, 2018

Hearing Location:            County Government Center

                                           Board of Supervisors Chambers

                                          1055 Monterey Street

                                          San Luis Obispo, CA 93408

Project Contacts

For more information please contact John Austin via email, Keith Miller via email, or stop by the Public Works Department office in downtown San Luis Obispo located at 976 Osos Street, Room 206