TVCSD Waste Water Treatment Plant

The System in Brief

Treatment PondsWastewater from the town and schools of Tomales flows or is pumped into the three-pond treatment system. Primary and secondary treatments occur there involving settling of solids and breakdown of the wastewater components. The three new aerated ponds are piped in series that allows the cleanest water from pond #1 to flow into pond #2, and again from pond #2 to pond #3. The wastewater is continually treated by settling and aeration as it moves from pond to pond. A final "polished" effluent is created in pond #3.

Treatment PondsThis three pond system is very new and was the final phase of the wastewater upgrades begun shortly after the formation of the district. The original system consisted of a single pond, and contained many years of accumulated sludge. The new system's ponds are lined with a 50 year plastic liner to insure there is no leakage into the surrounding ground. Additionally any of the three ponds can be taken offline for repairs without having to shut down the whole system.


Storage PondsThe treated effluent is then pumped to large storage ponds located a mile or so from the plant. Here the water is disinfected with chlorine and spray irrigated during the summer months onto the surrounding fields. These upper ponds serve two purposes: to give the wastewater additional time for further settling and biological breakdown, and to provide storage during the wet winter months when irrigation is not permitted. This irrigated pasture land is grazed by cattle to control vegetation growth.


The system is maintained and operated by Phillips and Associates of Napa, California. They are registered with the State Water Resources Control Board as a licensed contract operator, and are certified by the Department of Health Services to provide operations, management and maintenance services. They have been under contract to operate the system since the late 1990's. Approved System Operator Contract

Sewer System Management Plan (SSMP)

Tomales Village CSD's SSMP

On May 2, 2006, the State Water Resources Control Board issued Order 2006-0003, Statewide General Waste Discharge Requirements (WDR) for sanitary sewer systems. This Order was issued to ensure consistent and comprehensive regulation of publicly-owned sanitary sewer systems throughout the State, and to quantify and reduce Sanitary Sewer Overflows (SSOs).
The WDR requires all wastewater collection agencies with sanitary sewer systems more than one mile in length to electronically report SSOs to the State Water Resources Control Board monthly, which the TVCSD has done since 2007, and to develop and implement a Sewer System Management Plan (SSMP). The SSMP is a written document that details how the agency’s sanitary sewer system is operated, maintained, evaluated, and funded.
The completed SSMP includes eleven elements:
Legal Authority
Operation and Maintenance Program
Design and Construction Standards
Overflow Emergency Response Plan
Fats, Oils, and Grease Control Program
System Evaluation and Capacity Assurance Plan
Monitoring, Measurement, and Program Modifications
SSMP Audits
Communication Program

The Tomales Village CSD’s SSMP was adopted by the Board of Directors on September 12, 2012.

Solar Power

Solar Panels

The district's 31.8 kW DC solar system is complete and online. The power produced by this system will offset energy usage at the wastewater treatment plant, the irrigation field, the lower town lift station and the community park. There are two solar arrays, one near the ponds at the treatment plant and the other located at the irrigation field. Both systems will net meter from PG&E and could ultimately save $50,000 to $150,000 over the next 25 years depending on energy costs. A new state law allows the district to combine the meter readings from the park and the lift station allowing us to offset a major portion of those electricity bills also.

Solar power provides an environmentally friendly way to reduce energy costs and will offset 1,768,807 pounds carbon dioxide, 5,676 pounds of nitrous oxide not released, and 5,138 pounds of sulfur dioxide not released, the equivalent of 2,878,026 miles not driven.

Wastewater Overview

Below is a simple schematic of our wastewater system, from Home, businesses and schools to irrigation disposal.

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