Island County, WA Noise Ordinances: Decibel Limits (2026)
Key Facts
- Zone 2 requirement
- Minimum 25 dBA outdoor-to-indoor reduction
- Zone 3 requirement
- Minimum 30 dBA outdoor-to-indoor reduction
- Zone definition
- Ldn 60-70 (Zone 2), over 70 (Zone 3)
- Applies to
- New construction/alterations near airport facilities
- Enforcement point
- Building permit review, § 14.01B.020
Summary
Unincorporated Island County's numeric noise standard isn't a property-line nuisance limit; it's a construction rule tied to NAS Whidbey. Section 14.01B.050 requires new buildings and alterations in Airport Noise Zone 2 to cut outdoor-to-indoor sound by at least 25 dBA, and buildings in Airport Noise Zone 3, defined by higher aircraft noise levels, to cut it by at least 30 dBA.
All new structures and alterations to existing structures shall conform to the following minimum standard unless exempted in this chapter.A.Airport noise zone 2 shall have a minimum twenty-five (25) dba noise level reduction. Noise level reduction is to be measured outdoor to indoor noise; andB.Airport noise zone 3 shall have a minimum thirty (30) dba noise level reduction. Noise level reduction is to be measured outdoor to indoor noise; orC.Where noise sensitive activities are carried on in only a portion of new or reconstructed commercial buildings only those areas judged noise sensitive by the department need be protected.
Full Breakdown
01B, the Noise Level Reduction Ordinance, protects buildings near Island County's busiest airport facilities, principally NAS Whidbey Island, by requiring extra sound insulation rather than by capping noise at the source. 040 draws two airport noise zones based on the day-night average sound level, Ldn: Zone 2 covers areas with an Ldn of 60 to 70, and Zone 3 covers areas with an Ldn greater than 70. 050 then sets the numeric construction standard tied to those zones: new structures and alterations in Zone 2 need a minimum 25 dBA noise level reduction measured from outdoor to indoor sound, while Zone 3 buildings need a minimum 30 dBA reduction, and every building permit application for property in Zones 2 or 3 must be reviewed against this standard, with the Department able to refuse the permit if the design falls short.
090 spell out how to hit the 25 or 30 dBA targets: exterior walls need at minimum an STC-30 rating, windows at least STC-28 or three-sixteenths-inch glass, exterior doors at least STC-26, and every seam around windows, doors, foundations and utility penetrations has to be sealed, caulked or weather-stripped to stop air and sound leakage. 60.
Violations & Fines
Section 14.01B.020 makes compliance with the noise reduction standard a condition of the building permit itself: if the Department of Planning and Community Development determines a proposed design in Zone 2 or 3 doesn't meet the 25 or 30 dBA reduction, the permit is not issued. Because compliance is enforced at the permit-review stage rather than through a separate infraction, the practical consequence of ignoring section 14.01B.050 is a stalled or denied building permit until the design is revised to meet the required sound transmission ratings.
Frequently Asked Questions
What is the numeric noise reduction requirement for building in Island County's airport noise zones?
How are Airport Noise Zones 2 and 3 defined?
What wall and window ratings meet the 25 dBA noise reduction standard?
Does Island County have a general decibel limit for neighborhood noise?
Sources & Official References
Other rules in Island County
Compare Island County to another location·View the Washington noise ordinances overview
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