City of Mercer Island Water Supply Pipeline: Subcontractor Bid Package 001 - 10” Watermain Installation

City of Mercer Island Water Supply Pipeline: Subcontractor Bid Package 001 - 10” Watermain Installation Summary The City of Mercer Island is soliciting bids from qualified contractors for construction services associated with Replacement of the Water Supply Line project, located on the City of Mercer Island near the I-90 EB on-ramp at East Mercer Way. The pipeline alignment proceeds west onto SE 36th Street and climbs Gallagher Hill Road. Project documents are available under OpenGov project ID 2026-AFB-004. Questions should be submitted through OpenGov and sealed bids must be received electronically by the City via OpenGov no later than 2:00 pm on Tuesday, March 24, 2026. Contractors are responsible for allowing sufficient time for electronic transmission to ensure timely receipt. Late submittals will not be accepted. There will be no public bid opening. Bid results will be posted on the City Procurement Portal. https://procurement.opengov.com/portal/mercerislandwa/projects/241877 Background The City of Mercer Island’s Water Supply Pipeline project includes constructing a new 24-inch ductile-iron water transmission main. The new pipeline will run approximately 5,000 feet from the Boat Ramp area on East Mercer Way, north along East Mercer Way, west on SE 36th Street, southwest along SE Gallagher Hill Road, and east on SE 40th Street to connect with the existing system near 92nd Avenue SE. In addition to installing the new primary transmission line, the project includes replacement of roughly 1,500 feet of older 8- and 10-inch asbestos-cement distribution mains on Gallagher Hill Road, as well as construction of a new pressure-reducing valve (PRV) vault and updated system interconnections to improve supply reliability, pressure management, and fire-flow capacity. To support and protect the new water infrastructure, the project also includes a series of roadway, sidewalk, and streetscape improvements along SE 36th Street, Gallagher Hill Road, and SE 40th Street. These improvements include pavement reconstruction, new and ADA-compliant sidewalks and curb ramps, stormwater and utility adjustments, and updated pavement markings to enhance safety and mobility for all users. Together, the pipeline installation and corridor improvements will create a modern, resilient, and more easily maintainable water-supply corridor designed to provide long-term service reliability, improved water quality, and enhanced transportation infrastructure for the surrounding community. Timeline Advertisement Date: March 9, 2026 Question Submission Deadline: March 16, 2026, 2:00pm Question Response Deadline: March 19, 2026, 2:00pm Bid Due Date: March 24, 2026, 2:00pm Closing Date: Tuesday, March 24, 2026Organization: City of Mercer IslandPoint of Contact: clint.morris@mercerisland.gov