Occidental County Sanitation District (OCSD) and Graton Community Services District (Graton) both have sewer service charges which are among the highest rates in California.
The high rates are due to the cost associated with operating a small wastewater systems in areas with stringent wastewater treatment requirements. OCSD is currently hauling wastewater from an Occidental lift station to the Airport/Larkfield/Wikiup Sanitation Zone (ALWSZ) treatment plant for treatment and disposal in north Santa Rosa.
Feasibility Study of combining Occidental and Graton wastewater treatment
In 2021 OCSD and Graton conducted a feasibility study to assess transporting untreated wastewater from OCSD to Graton for treatment and disposal, to assess the capacity of the Graton wastewater treatment plant to treat and dispose of the total combined flow, and to construct a pipeline from OCSD to Graton to reduce costs and provide Graton with additional income necessary to prevent significant rate increases in the near future. The Occidental to Graton Wastewater Pipeline Feasibility Study was completed in 2022.
The feasibility study concluded that constructing a pipeline to transport wastewater from OCSD to Graton is feasible, if 50 percent of the capital costs are funded through grants, low-interest loans or other non-ratepayer sources. If funding is not available, the study recommended that wastewater be trucked to Graton for treatment.
Current status of the project
Thanks to the efforts of Senator Alex Padilla, in May 2025, OCSD secured a $1.45 million grant through the U.S. Environmental Protection Agency for the Occidental County Sanitation District Pipeline Design project to provide more efficient water quality management for the communities of Occidental, Graton and surrounding areas. The project will include 90% pipeline design and environmental analysis. OCSD executed the consultant agreement in early October, and the environmental compliance documentation and substantial design plans are anticipated to be completed by December 2026. OCSD will be seeking State Revolving Funds for final design and pipeline construction.
Estimated Timeline
- Pipeline design grant funding application (Environmental Protection Agency - EPA): October 2023-January 2024
- EPA Grant Approval: May 2025
- Pipeline design and CEQA document preparation: October 2025 –December 2027
- Construction loan application (State Revolving Fund): September 2026 – December 2027
- Final design, Permits and Property Acquisition: January 2028 – December 2029
- Construction: January 2030 – December 2031
- Outreach: Ongoing
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Community Meetings
Oct. 15, 2026 Project Update Occidental-Graton Wastewater Transfer Pipeline
Aug. 19, 2025 (in-person only) Special Joint Meeting with the Forestville Water District Board of Directors.
Oct. 23, 2024 (in-person only) Occidental Town Hall
Sept. 18, 2023 (in-person only) Graton Community Services District regular meeting
Dec. 15, 2022 (virtual) 5 - 7 p.m. Board Meeting - Special Meeting of the Graton Community Services District Board of Directors
Oct. 11, 2022 (multi-access) Occidental Community Services District regular meeting. Sonoma Water Principal Engineer Carlos Diaz provided an update on the project and feasibility study findings.
Feb. 10, 2022 (virtual) 5:30 - 7 p.m. with Sonoma County 5th District Supervisor and Sonoma Water Director Lynda Hopkins.
Occidental County Sanitation District to Airport-Larkfield-Wikiup Sanitation Zone Wastewater Transport Project
In December 2017, the Board of Directors of Sonoma Water, which operates the Occidental County Sanitation District’s Wastewater Treatment Facility, approved a project for transporting untreated wastewater from the Occidental County Sanitation District to the Airport-Larkfield-Wikiup Sanitation Zone for treatment, storage, and reuse to avoid future discharges into Dutch Bill Creek and potential violations of the Occidental County Sanitation District.
The project will allow the Occidental County Sanitation District to comply with conditions set forth by the North Coast Regional Water Quality Control Board in Order No. R1-2012-0101. This order requires the Occidental County Sanitation District to cease discharging secondary treated recycled water to Dutch Bill Creek by Jan. 31, 2018. The project includes transporting untreated wastewater to the Airport-Larkfield-Wikiup Sanitation Zone, wastewater treatment facility for treatment, storage, and disposal. The Airport-Larkfield-Wikiup Sanitation Zone wastewater treatment facility currently treats wastewater to secondary and tertiary standards and utilizes irrigation of agricultural lands for disposal of secondary and tertiary-treated recycled water.
- FINAL - Initial Study and Negative Declaration of Environmental Impact
- DRAFT - Initial Study and Negative Declaration of Environmental Impact
- Notice of Availability/Intent to Adopt
- Notice of Preparation of Initial Study - Occidental-to-Airport Wastewater Transport Project
- OCSD Timeline: Past Milestones and Steps Toward Solutions