Cotati City Council
Agenda Staff Report
Item type: REGULAR AGENDA (ACTION)
To: City Council
Subject: COST-SHARING AND PROJECT ADMINISTRATION
AGREEMENT FOR THE HELMAN LANE–BLODGETT
STREET WATER LINE EXTENSION
Date: October 13, 2026
Written by: Craig Scott, Director of Public Works/City Engineer Recommendation
It is recommended the City Council adopt a resolution authorizing the City Manager to execute a cost sharing agreement with the Marin-Sonoma Mosquito and Vector Control District to construct the Helman-Blodgett water main extension, subject to final acceptance by the City Attorney.
Background
The City’s Water Distribution Master Plan (Master Plan) identifies capital improvements needed to meet the needs of existing customers and those needed to meet the projected buildout of the water system to implement the growth provided for in the City’s General Plan. These improvements mainly consist of pipelines, tanks, wells, and pump stations and are phased to address the most pressing needs of the system and anticipated timing of future growth.
Analysis/Discussion
Water systems are to meet performance criteria for water pressure and water quality under a variety of demand conditions. Therefore, capital improvements, including pipelines, are constructed with or in anticipation of new development. With the development of the PODs development in 2022, the Blodgett Cul-De-Sac was constructed and the water main extended and stubbed out for future extension across the property to the south (owned by the Marin/Sonoma Mosquito & Vector Control District [District]) for connection to the pipeline in Helman Lane.
The City’s Master Plan identifies this connecting pipeline improvement as “P-10.” which connects the 10-inch diameter pipeline in Blodgett Street to the 12-inch diameter pipeline in Helman Avenue. The proposed pipeline is a “Category 4” improvement, as defined in the Master Plan to provide main looping in future development areas. P-10 is identified to be constructed in the 2022 to 2026 period. Therefore, when the District approached the City sometime in 2024 with plans to redevelop their property, the City included the pipeline into those early discussions.
The subsequent plans that emerged showed an alignment for the pipeline, nearer the eastern boundary and beneath the proposed parking lot, that appears to be most practical to both parties; mainly because it lines up with the pipeline in Blodgett and the pipeline is below the future parking lot and along one side of the parcel.
In recent months, the District’s efforts have advanced and have submitted a Development application with the City and seek a Cost sharing agreement with the City to cover costs associated with the environmental, design, and construction of the pipeline. The District and City staff and legal representation have negotiated the attached agreement and recommend it for approval substantially in the form presented subject to final review and approval by City legal counsel. The main provisions of the Cost Sharing Agreement are as follows:
1. District incorporates environmental, design and construction of pipeline into their design/build contract
2. Not to exceed total cost for pipeline is $585,450.93
3. City involved in review of change orders
4. Pipeline to be in maintenance easement. The District can relocate the pipeline at its own expense.
5. Water line under parking lot is not responsible for wetland or CTS habitat mitigation of the parking lot disturbed area.
6. Progress Billing: City to be billed monthly. Anticipates Soft costs FY26/27 and construction kick-off in FY27/28.
7. Construction Method. Wetland and CTS habitat is to be avoided by trenchless methods from the Cul-De-Sac to the proposed District parking lot. Along the parking lot, the proposed method is traditional open cut trenching.
The District was to act on the agreement in substantially the form as attached at their meeting on October 12, 2026. Following Council action tonight, staff and the City Attorney’s office will make any non-substantive corrections and legal edits and move to execute the agreement.
Financial Considerations
This P-10 pipeline is identified in the master plan as a future benefit pipeline to the City and as such using this cost sharing agreement allows the City to build out the infrastructure at a reduced total cost. The full cost of the agreement as outlined totals $585,450.93. Currently only the design and environmental preconstruction “soft costs” are being considered for completion within the current fiscal year with construction to follow in fiscal year 27/28. As such, City staff are requesting a budget amendment and appropriation for this initial environmental and design at an amount not to exceed $112,245 from the water capital fund. The remainder of the funds will be considered during the Biannual FY27/28-FY28/29 Budget process.
Environmental Issues
The Hellman Lane-Blodgett Street Pipeline Extension (P-10 Pipeline) is subject to environmental review under CEQA. The Subject Cost Sharing Agreement provides for CEQA review including preparation of an Initial Study and related documents through the District Consultants for the City’s independent review and adoption and the City will act as a responsible agency in approving the District Project. Based on the trenchless method, impacts attributable to the water line on wetlands and CTS habitat are anticipated to be limited to be no more than 0.1 acre for purposes of the Cost-Sharing Agreement.