Cotati City Council
Agenda Staff Report
Item type: CONSENT CALENDAR (ACTION)
To: City Council
Subject: CONSIDERATION TO ADOPT A RESOLUTION
APPROVING A PROFESSIONAL SERVICES AGREEMENT
TO PROVIDE CONDITION ASSESSMENTS OF THE CITY'S
SEWER LIFT STATIONS AND WELL SITES
Date: October 28, 2025
Written by: Craig Scott, Director of Public Works/City Engineer Recommendation
It is recommended the City of Cotati City Council consider and adopt a resolution approving a Professional Services Agreement with Schaaf and Wheeler to prepare condition assessments of the City’s sewer lift stations and well sites and authorizing the City Manager to execute said agreement.
Background
The City owns and operates a public sewer system and a public water system, and these systems require ongoing maintenance and periodically condition assessments to determine any equipment replacement and/or site remediation needed. These efforts are to ensure the safe and reliable operation of these systems.
Analysis/Discussion
The City has four sewer lift stations and three drinking water wells. The intent of the proposed condition assessment of these facilities is to identify components that are reaching the end of their useful lives and subject to failure. These components can be proactively replaced or renewed before they fail to improve the reliability of these systems.
The lift stations receive sewage through gravity flow, and each has two submersible pumps which operate on a flow sensor. Each station is submersible which means the pumps, piping, and sensors are contained in a well filled with sewage, and the equipment is subjected to a highly corrosive environment. The well containing the sewage, pipes entering and existing with the wet well, equipment, sensors, and rest of the infrastructure is to have their condition assessed to determine the need for renewal and/or replacement.
The drinking water system’s three wells each have infrastructure consisting of the well column, casing, submersible pump, electrical system, sensors, treatment system, and for two of the wells, granular activated carbon filtration systems. These sites are monitored continuously by instrumentation for proper operation and are automatically shut down if critical parameters are not met. Additionally, each site is inspected daily by Public Works Staff, and water samples are collected and sent to a lab for analysis of water quality. A condition assessment would identify renewal and/or replacement needs of the components and factor in their visual condition, operating within design parameters, and expected life.
In June 2024, the City issued a Request for Proposals for engineering services including condition assessments and received 16 proposals. After evaluating the proposals, Staff determined Shaaf and Wheeler were the most qualified to provide condition assessment services.
In late 2024, Staff requested that Schaaf and Wheeler provided a proposal to do three discrete projects within the overall scope of work, as detailed below. • Perform condition assessments on the City’s sewer lift stations and its three drinking water wells. This is a general system wide assessment of the wells and sewer lift stations.
• Preliminary Design of backup power generators at two critical sewer lift stations, both in the City’s “bird” section.
• A detailed review of Well 2, which has been offline since this summer, including related rental of a water storage tank and water quality sampling costs.
The proposed scope of work essentially dedicates half of the work effort/fee to evaluate and provide recommendations for overall improvements to the three (3) municipal wells and the four (4) sewer lift stations. This includes on-site visits to review the infrastructure and staff interviews, as well as reviewing as-builts, water quality data, corresponding technical memorandums summarizing the review, recommendations and costs and preliminary design of generator backups at the two (2) sewer lift stations in the “bird” section of the City. Note that Task 4 is not proposed to be authorized under this scope, instead relying on the technical memorandums.
The other approximately half of the work effort/fee is a detailed “deep dive” evaluation of Well 2, which is a critical component of the water system in Cotati, particularly during droughts and to moderate wholesale water purchases during high demand times of year. To save costs, staff are proposing to rent a water storage tank and conduct water quality sampling directly. The scope of work includes a detailed review of water quality data and analysis of potential treatment alternatives. Finally, the work would conclude with a preliminary design of the proposed treatment system.
Note that there is an option scope item to conduct “zonal water quality sampling” that staff are not currently recommending. For water wells, there is a method to take discrete water quality samples at different depths along the screened interval(s). This type of zonal water quality sampling is typically employed if it is suspected that a particular constituent is coming from a discrete layer in the aquifer. If this were the case, in theory, the zone could be blocked off in the well to avoid pulling in this water and potentially avoid the need for a surface treatment system.
If, during the evaluation of Well 2, this seems to be likely, staff will revisit this.
If approved, the services would be conducted through the end of this year with deliverables due in early 2026. Following completion of these services, the City would include identified renewal and replacement projects in its five-year Capital Improvement Program.
Financial Considerations
With the removal of Task 4, the total not to exceed contract amount is $278,799. Both the water samples and the pumped water storage tank proposed to be rented by the City for the Well 2 evaluation are additional expenses estimated not to exceed $15,300. Therefoere, the total project cost is proposed to not exceed $294,099.
The City’s Fiscal Years 25/26 – 26/27 Adopted budget includes the following in the first year:
• Water Renewal and Replacement $150,000
• Sewer Renewal and Replacement $70,000
The Schaaf and Wheeler proposal is $296,979 in total, after removing Task 4 the adjusted total is $278,799 which includes a total of $210,413 for Water and $68,386 for Sewer. This project also requires a storage tank rental for the Well 2 testing and Water quality samples before discharge of the stored water which are estimated at $5,300 and $10,000 respectively. This creates a total cost of $225,713 for the Water fund and $68,386 for the Sewer fund. This leaves the Sewer project just within budget but the Water fund over budget by $75,713.
To cover the budget shortfall for Water, staff propose using the corresponding unappropriated fund balances. Please see the attached proposed budget amendment.
For the Water Fund, the impact to fund balance was previously reduced with the deferral of the Distribution Monitoring Project ($130,000) to fund the Emergency Water Repairs Project ($73,191). The difference of $56,809 will now be returned to the unappropriated fund balance and will be used to partially offset the proposed project.
In addition to these hard costs, public works field crew will be required to provide an estimated 28 hours to tie in the storage water tank as well as facilitate the sample testing. The total estimated cost of staff time is approximately $5,340 using the current billing rate. These costs are already included in the budgeted salary and benefits, and as such no budget amendment is required.
Environmental Issues
This action is found to qualify for a Class 1 Categorical Exemption under CEQA Section 15301 in that the project consists of the operation, repair, maintenance, permitting, leasing, licensing, or minor alteration of existing public or private structures, facilities, mechanical equipment, or topographical features, involving negligible or no expansion of the existing or former use.