Sammamish, WA Environmental Rules: Erosion Control (2026)
Key Facts
- ESC required
- On every clearing/grading site, permit or not
- Excavation limit
- 10 feet, SMC 16.15.090(2)(a)
- Fill limit
- 5 feet; over 4 feet must be engineered
- Permit term
- Up to 2 years, renewable every 2 years
- Liability insurance
- $100,000/$300,000/$50,000, waived under 10,000 cu yd
- Work hours
- 7:00 a.m. to 7:00 p.m.
- Wet-season cure period
- 24 hours after a notice of violation
Summary
Sammamish requires erosion and sediment control on every site that is cleared or graded, whether a permit is needed or not. SMC 16.15.090 makes the property owner responsible for keeping sediment out of drainage facilities, streams, wetlands and neighboring lots, backs it with tighter wet-season rules, and gives violators just 24 hours to fix a failure before work can be shut down.
Any activity that will clear, grade, or otherwise disturb the site, whether requiring a clearing or grading permit or not, shall provide erosion and sediment control (ESC) that prevents, to the maximum extent possible, the transport of sediment from the site to drainage facilities, water resources, and adjacent properties. Erosion and sediment controls shall be applied as specified by the temporary ESC measures and performance criteria and implementation requirements in the City's erosion and sediment control standards.
Official source re-checked September 8, 2026: no newer edition of the code had been published (publisher’s edition: current through Ordinance O2026-598, and legislation passed through August 18, 2026).
Full Breakdown
090(1) requires ESC on any activity that clears, grades or otherwise disturbs a site, permit or not, applying the City's temporary ESC measures, performance criteria and implementation standards to prevent sediment from reaching drainage facilities, water resources and adjacent properties. 070 for most grading, issued by the Director for up to two years and renewable every two years, with plans typically stamped by a Washington-registered civil engineer or landscape architect. 090(2)(a): excavation cannot exceed 10 feet and fill cannot exceed five feet, though a Type 1, 2 or 3 permit can approve limited deviations, for example where a driveway would otherwise exceed 15 percent slope, and all fill over four feet must be engineered.
080. 120(4) layers on extra scrutiny: the Director must approve clearing and grading in writing based on site conditions and proposed ESC measures, and if silt-laden runoff leaves a site or an approved ESC plan is not maintained, the City issues a notice of violation. Routine ESC maintenance, existing utility upkeep, sites achieving 100 percent on-site infiltration, and unpermitted single-family landscaping stay exempt from the seasonal rules.
Violations & Fines
Starting work without the required clearing and grading permit exposes the responsible party to civil penalties under SMC Title 23. Once a notice of violation issues for an ESC failure, SMC 16.15.120(4)(e) gives the site 24 hours to fix the problem; if it isn't repaired, the inspector can order clearing and grading halted, aside from ESC repair and maintenance work, until the following March 31, and civil penalties continue to accrue under the City's compliance code.
Frequently Asked Questions
Do I need a permit to clear or grade my Sammamish property?
How much can I cut or fill without extra engineering?
What happens if my construction site lets sediment run off during the rainy season?
Does a grading permit require insurance?
Sources & Official References
Other rules in Sammamish
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Erosion Control in Nearby Cities
How other cities in King County handle erosion control.