Madison Valley Stormwater Storage Facility (Image: Karen Kiest Landscape Architects)
The Seattle City Council’s Governance and Utilities Committee chaired by District 3’s Joy Hollingsworth will consider legislation Thursday to update the city’s stormwater laws, shaping the requirements for development, roadways, utilities, and maintenance work in the city.
The committee’s work is hoped to update city code to meet requirements by the state’s July deadline.
The stormwater code guides how water can enter the city’s systems and shapes everything from project design to construction runoff. The code includes onsite stormwater management, flow control and water quality treatment requirements for development.
In a presentation (PDF) for Thursday’s session, officials say the state changes will bring “very few new requirements” for city and private construction and maintenance work and predict “minimal fiscal impacts to the City and capital projects.”
But the costs won’t be zero. For the Department of Transportation, for example, costs are estimated to rise $1.8 million under the new standards in 2031, the first year new projects would be fully subject to the new code.
Seattle Parks, for example, could see “cost increases on a wide variety of project types including: accessibility projects, play area renovations, construction of new facilities, pathways and sidewalks, athletic fields, park irrigation and drainage, dog off-leash areas, and beaches and shoreline structures (piers, floats, etc.),” as a result of the 2026 Stormwater Code Update, according to a council analysis (PDF).
Increased and better processes and infrastructure will also be required for private projects.
In addition to new requirements, the updated code would bring the end of past exceptions including the removal of stormwater exemptions for utility work and pavement maintenance for private projects.
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