Mill Creek council approves $2.21 million to repair 1,016 failing catch basins after mandatory inspections

The Mill Creek City Council voted unanimously Tuesday to amend the city’s capital improvement plan and appropriate $2,210,000 from the surface water utility fund to begin a citywide catch-basin repair program ordered under the 2024 Western Washington Phase II municipal stormwater permit.

The action follows inspections that found 1,016 catch basins — about 27.5 percent of the city’s 3,689 catch basins — failed or in need of maintenance. Public works staff told the council the work is required by the city’s permit and must be completed in two groups under the timeline the Department of Ecology sets.

“This allows us to discharge our surface water that we collect from our roadways ... into these waters of the state,” Public Works staff member Carmody told the council during a presentation on the program’s status and schedule. Carmody said the city inspected 3,128 basins on lower-traffic neighborhood streets and 561 on higher-traffic roads and highways and identified 1,016 basins with defects ranging from cracked risers to exposed rebar and failed sumps.

Why it matters: the state stormwater permit requires catch-basin inspections every two years and sets repair deadlines tied to whether the repairs are performed in-house or as part of a capital project. If the city performs repairs with its crews, many fixes must be completed within six months; bundling work into a capital project extends that deadline to two years. Ecology enforces the permit.

Council heard a detailed tally of the deficiencies: 731 basins were tagged as the higher-priority Group 1 work, and 285 basins comprised Group 2. Group 1 repairs are due by Nov. 24, 2026; Group 2 repairs are due by June 10, 2027. Carmody’s cost estimate placed Group 1 at roughly $2.5 million and Group 2 at about $2.0 million, for a total project estimate near $4.54 million.

To start immediate work and meet the permit timeline, staff proposed deferring or delaying portions of other surface-water capital projects and increasing the surface-water program budget for this biennium. Carmody said staff identified $900,000 of near-term capital that could be deferred and proposed increasing the surface-water capital program from $5,005,000 to $7,125,000 for the biennium.

Council action and next steps: Councilor Cavalieri moved and the council approved an ordinance amending the 2025–2030 capital improvement plan and appropriating $2,210,000 from the surface water utility fund. The motion passed unanimously. The adopted budget amendment gives staff authority to solicit an engineering firm and issue an invitation to bid; staff said they expect a notice to proceed for the engineer in August and to begin contractor work in September, working through the dry-weather season.

City staff emphasized the schedule is aggressive because much of the work must be performed during dry weather, and that contractors will be required to meet the performance schedule. Carmody said crews and contractors will prioritize work that avoids extended lane closures on state highways and that some night work will be necessary on major arterials.

Council discussion focused on the project’s scope, fund reserves and timing. Finance staff noted the surface-water fund would have roughly $1.12 million in reserves at the end of the biennium under the proposed plan, and that staff would return in the fall with options — including rate adjustments, one-time assessments or borrowing — to stabilize the utility over the midterm.

“Due to the quantity of these repairs, we’re going to do it as a capital project,” Carmody told council. “That gives us two years to repair these. Group 1 will be due 11/24/2026 and Group 2 is due 06/10/2027.”

What remains uncertain: staff said the city has limited historical inspection records and that much of the deferred maintenance has accumulated over decades. They also warned that the city’s uninspected 18-inch-plus pipes will require further inspection and rehabilitation in later years, and that those costs could be substantial.

Ending: Council’s appropriation funds the immediate capital bid and contracting steps to address the most urgent catch-basin repairs. Staff will return this fall with a six‑year financial projection for the surface-water program and recommendations on rates, borrowing or other tools to replenish reserves and cover future pipe rehabilitation work.