Snohomish County, WA Noise Ordinances: Aircraft Noise (2026)

SCC 10.01.050 is the exemptions section of Snohomish County's noise ordinance, chapter 10.01 SCC, and subsection (1)(a) is the aircraft carve-out: sounds originating from aircraft in flight and sounds which originate at airports and are directly related to flight operations are exempt at all times from the maximum permissible sound levels set in SCC 10.01.030(2) and (3), the numeric decibel limits that otherwise govern sound crossing a property line. That exemption applies around the clock, day or night, and it sits alongside 18 other blanket exemptions in subsection (1), covering everything from railroad and vessel operations to fire alarms and officially sanctioned parades.

A second, narrower exemption in subsection (2)(g) separately excuses sounds created by aircraft engine testing and maintenance from the maximum permissible levels, but only during daytime hours, meaning that category of ground noise, unlike in-flight and airport-flight-operations noise, loses its exemption after dark. Both exemptions carry the same caveat that runs through all of SCC 10.01.050: if the source of the sound is subject to a Conditional Use Permit or a SEPA environmental determination, the exemption only extends as far as the noise conditions of that permit or determination allow, so a permitted airport expansion or heliport, for instance, could still face project-specific noise conditions despite the blanket aircraft exemption.

The exemption reflects the reality that airport noise, including operations at Snohomish County Airport (Paine Field), is governed primarily by FAA regulation and federal noise-compatibility planning rather than local decibel limits. Chapter 10.01 SCC is otherwise enforced by the county noise administrator and the sheriff's office, with civil infractions running from $50 to $1,000 and repeat violations escalating to misdemeanors under SCC 10.01.080, but none of that enforcement machinery reaches ordinary aircraft flight or airport flight-operation noise because SCC 10.01.050(1)(a) removes it from the ordinance's reach entirely.