Lynnwood, WA Environmental Rules: Stormwater Management (2026)
Key Facts
- Permit trigger
- 2,000+ sq ft disturbance or impervious surface
- Category 2 trigger
- 5,000+ sq ft or 0.75+ acre to landscaping
- Governing manual
- WA Stormwater Manual for Western WA
- Special basin standard
- Perrinville Creek elevated flow control
- Administered by
- Lynnwood public works department
Summary
Lynnwood requires a stormwater permit and site plan for projects disturbing 2,000 square feet or more of land or adding new or replaced impervious surface, under LMC Chapter 13.40. The rules implement the state's Western Washington Phase II Municipal Stormwater Permit issued by the Department of Ecology.
The city council finds that this chapter is necessary to: promote sound development policies and construction procedures which respect and preserve the city's watercourses; minimize water quality degradation; prevent sedimentation of creeks, streams, ponds, lakes and other water bodies ... This chapter is also necessary to control stormwater runoff generated by development, redevelopment, construction sites, or modifications to existing stormwater systems that directly or indirectly discharge to the city stormwater system, in a manner that complies with the Western Washington Phase II Municipal Stormwater Permit issued by the Washington State Department of Ecology. ... The requirements of this chapter shall apply to all actions requiring the approval or issuance of a permit by either the development and business services department or the public works department, or projects involving 2,000 square feet or more of land-disturbing activity, new impervious surface, or replaced impervious surface.
Official source re-checked September 8, 2026: no newer edition of the code had been published (publisher’s edition: current through Ordinance 3512, passed May 26, 2026).
Full Breakdown
40 of the Municipal Code, Stormwater Management, administered by the public works department. 020 sets the applicability trigger: the chapter's requirements attach to any action needing a permit from the development and business services department or public works, or to any project involving 2,000 square feet or more of land-disturbing activity, new impervious surface, or replaced impervious surface. 055. 070 and obtain final approval before construction begins; skipping that step exposes the project to revocation of all its permits. 060 because of that basin's sensitivity, requiring predevelopment flow durations to be maintained across a wider range of storm events than elsewhere in the city.
Violations & Fines
LMC 13.40.150 makes noncompliance with the stormwater chapter a violation subject to enforcement by the public works department under LMC 13.40.160, with penalties set out in LMC 13.40.170 and an appeal path through LMC 13.40.180. Starting covered construction without an approved stormwater site plan can also trigger revocation of all permits issued for the project under LMC 13.40.070(C).
Frequently Asked Questions
When does Lynnwood require a stormwater permit for a project?
What happens if I start construction without an approved stormwater plan?
Why does Lynnwood single out Perrinville Creek for stricter rules?
Sources & Official References
Other rules in Lynnwood
Compare Lynnwood to another location·View the Washington environmental rules overview
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Stormwater Management in Nearby Cities
How other cities in Snohomish County handle stormwater management.