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San Luis Obispo County, California

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Los Osos Wastewater Project

Mission Statement: To evaluate and develop a wastewater treatment system for Los Osos, in cooperation with the community water purveyors, to solve the Level III water resource shortage and groundwater pollution, in an environmentally sustainable and cost effective manner, while respecting community preferences and promoting participatory government, and addressing individual affordability challenges to the greatest extent possible.

Collection System Construction

  Dig Los Osos Logo

 Visit , a website developed specifically for the project collection system construction. DigLosOsos provided regularly updated schedules, maps of construction progress, information on expected traffic impacts, and contact information. With completion of pipeline installation, DigLosOsos is no longer being updated with new information.  However, information on the pipeline construction is still available to review.


The County is currently implementing a water conservation program, which includes  rebates for water saver fixtures.

Click here for a list of plumbers for the retrofit program (These plumbers are not pre-approved or pre-qualififed but have shown interest in the retrofit program).

Brochure  for Los Osos Water Conservation Rebate Program.

Visit the new website devoted to the Los Osos Water Conservation Rebate Program



Representatives from the County are available to help residents and businesses review lateral plans for their property, discuss costs, and answer any other questions regarding the Los Osos Wastewater Collection System Project.

Contact the County at (805) 788-2114 or with comments or questions, or to schedule an appointment. 

Note: Regular office hours will no longer be held at the 2025 10th Street office after May 29, 2014.


Recent News and Events 

Los Osos Wastewater Project Public Forum on February 25, 2015 (4 - 5 pm, or  6 - 7 pm)

at the Los Osos Middle School (1555 El Moro Avenue, Los Osos, CA 93402)

All is quiet on the streets of Los Osos and construction of the Water Recycling Facility is nearing the halfway point. Please join us on Wednesday, February 25th, to learn about the project status and begin planning for your 2016 sewer lateral connections.  Location is at the Los Osos Middle School. Learn about upcoming workshops for grants and loans for low income residents, as well as, green options for re-purposing septic systems.

January 6, 2015: Baseline Groundwater Quality Report released to the Regional Water Quality Control Board. This was an additional requirement under the WDR R3-2011-0001. This report contains the latest Nitrate concentrations and Groundwater levels.

January 5, 2015: Project Construction Update for the month of November 2014.

November 30, 2014: Project Construction Update for the month of October 2014.

October 29, 2014: Project Construction Update for the month of September 2014.

October 28, 2014: Board of Supervisors consent agenda items 14 and 15 to record the Notice of Completion and Acceptance for the Areas A&D Contract and Areas B&C Contract.  Read the staff reports - Areas A&D, Areas B&C. Read the staff report for Item 14.  Read the staff report for Item 15.

October 7, 2014: Seawater Intrusion Monitoring Update released by the ISJ Working Group.

September 29, 2014: Project Construction Update for the month of August 2014.

September 25, 2014: Los Osos Wastewater Project Update Postcard.

September 25, 2014: Public Tour of the Water Recycling Facility construction site from 5pm to 6pm.  For more information and to sign up to attend, contact Rosalyn Piza at or (805) 788-2759. 

August 29, 2014: Project Construction Update for the month of July 2014.

July 31, 2014: Project Construction Update for the month of June 2014.

June 30, 2014: Project Construction Update for the month of May 2014.




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Public Works is located in room 207B of the old Courthouse building,

Corner of Palm and Osos Streets in San Luis Obispo.

Office hours are Monday to Friday 8:00 AM to 5:00 PM

General information phone number is (805) 781-5252