CITY OF SAN MATEO
CITY OF SAN MATEO
Agenda Report
City Hall
330 W. 20th Avenue
San Mateo CA 94403
www.cityofsanmateo.org
Agenda Number: 13 Section Name: CONSENT CALENDAR Account Number: 72-4671 File ID: 25-10554 TO: City Council
FROM: Alex Khojikian, City Manager
PREPARED BY: Public Works Department
MEETING DATE: December 1, 2025
SUBJECT:
Wastewater Treatment Plant Annual Major Components Improvements — Agreement RECOMMENDATION:
Award an agreement to C. Overaa & Co. for the Annual Major Components 3 Water Pumping Improvements and Ferric Chloride to Combined Sludge Line Project in an amount not to exceed $2,377,000; establish a contingency reserve in the amount of $475,400; and authorize the Public Works Director to execute the agreement in substantially the form presented and issue change orders as allowed by the contract documents and within the contingency amount.
BACKGROUND:
The Clean Water Program (CWP) Annual Major Components (AMC) Projects includes several capital improvement projects that are currently under development or under construction and are intended to upgrade or rehabilitate aging infrastructure in the City’s sewer collection system and Wastewater Treatment Plant (WWTP). The 3 Water Pumping Improvements and Ferric Chloride to Combined Sludge Line project was identified as one of these projects.
The project comprises of three major components. The first includes replacement of the four existing 3 Water pumps and ancillary systems (”3 Water” refers to disinfected effluent suitable for reuse throughout the WWTP). The 3 Water pumps system provides reclaimed flush water to the centrifuges, foam removal at the gravity thickeners, and hose bibs around the plant. The existing 3 Water pumps are nearing the end of their useful lives. The pump pedestals are corroded, and the piping is degraded. The project includes replacement of 3 Water pumps, associated piping, demolition of existing piping and appurtenances, and installation of a new valve on a 14-inch reclaimed water line.
The second component includes replacement of the existing 10,000-gallon ferric chloride tank with a smaller day tank.
Field investigations revealed that the slab under the existing ferric chloride tank is under stress and would require a load under 6,000 gallons to avoid retrofit work. The day tank would be supplied from the new ferric chloride chemical storage tanks constructed as part of the WWTP Upgrade and Expansion (GMP-3) Project. This would also reduce the chemical truck loading locations from two locations to one location at the new chemical storage tank area. The project includes the ferric chloride day tank, new ferric chloride metering pumps, a ferric chloride transfer pump, connections to ferric chloride yard piping and associated appurtenances, and demolition of existing piping and appurtenances.
The third major component of the project includes replacement of four existing spent backwash pumps to four stormwater pumps to drain the detention basins that are used to retain storm water at the WWTP. The backwash pumps were originally used to convey spent backwash from the filter vessels. The filter vessels are not in service and have been abandoned and removed. The project includes construction of stormwater pump improvements in the Pump Pit, including demolition of existing spent backwash pumps, installation of new stormwater pumps and associated discharge and suction header. Potholing is included to locate existing utilities and stormwater connections, including excavation, backfill, compaction, pavement restoration, demolition of existing yard piping and connections to existing piping, as needed.
CITY OF SAN MATEO
Bid Results
The Engineer’s Estimate for the Project is $4,820,000. The Project was advertised on October 2, 2025, and a total of six (6) bids were received and opened on November 6, 2025. The bids received are listed below in order of increasing bid amounts. While the bids received were lower than the Engineers Estimate, it should be noted that the Engineers Estimate was a conservative estimate based on previous bids that were influenced by supply changes issues and higher material costs as a result of COVID. The bids we received on this project may be an indication that the impacts to the supply chain of material are being resolved. Staff reviewed the bids and determined that C. Overaa & Co. is the lowest responsive and responsible bidder, with a bid of $2,377,000 (comparison to Engineer’s Estimate in Attachment 2). Therefore, staff recommends for Council to award the construction agreement to C. Overaa & Co. Staff also recommends a $475,400 contingency be established to address unknown challenges due to the complexity of sequencing and minimizing impact to operations when replacing existing infrastructure, underground and electrical tie-ins, and coordination with concurrent projects.
Bid Results
Overaa $2,377,000
Mountain Cascade $2,780,500
GSW Construction $3,058,755
Western Water $3,492,000
Disney Construction $3,770,000
Corcus $4,032,500
BUDGET IMPACT:
There are sufficient funds available in the CWP Annual Major Components (46t090) project budget to award this contract and establish the contingency.
ENVIRONMENTAL DETERMINATION:
In accordance with CEQA Guidelines Section 15301, this project is categorically exempt from CEQA as an ‘existing facility’ in that it involves negligible or no expansion of use.
NOTICE PROVIDED
All meeting noticing requirements were met.
ATTACHMENTS
Att 1 – Agreement
Att 2 – Bid Results
STAFF CONTACT
Thomas Ruark, Senior Project Manager
[email protected]
650-522-7280
Thomas Williams, Engineering Manager
[email protected]
650-522-7307