The Tacoma City Council has adopted Ordinance 29107, approving an updated Stormwater Management Manual and amending the Tacoma Municipal Code regarding allowable discharges. Taking effect on July 1, 2026, this comprehensive update fulfills a five-year requirement mandated by the Washington State Department of Ecology under the City’s municipal stormwater permit. The adopted ordinance reflects a year and a half of thorough technical review, public comment, and a strict state equivalency process designed to protect the health of local waterways.
By aligning Tacoma’s standards with the 2024 state manual, the City maintains technical equivalency with neighboring jurisdictions, including the City of Seattle, King County, and Pierce County.
The updated manual provides developers with a wider array of flexible, performance-based tools to manage stormwater naturally and effectively on both new and redevelopment sites. These additions include a variety of green stormwater best management practices, such as infiltration swales, flow dispersion, and ballasted sidewalks. The manual also introduces new requirements for tree planting and the retention of existing healthy trees, a method identified as practical and effective for mitigation of stormwater impacts on-site.
To further safeguard Tacoma’s environment, the manual implements practical, science-based protocols to manage specific pollutants, notably introducing new Polychlorinated Biphenyls (PCB) pollution control requirements for the demolition, renovation or routine external building washdown of commercial, industrial and multi-story residential buildings constructed or renovated between 1950-1980. Single-family residential homes are exempt.
With the ordinance now adopted, City staff are focusing on outreach and education ahead of the implementation date.