Sensitive land uses near highways and major truck routes
Seattle Mun. Code § 23.42.047
in effectAny dwelling unit, school, or child care center that is located within 600 feet of an interstate, highway, or designated major truck street right-of-way, or railroad must incorporate the following features to maintain indoor air quality and reduce noise intrusion: A. Sound-insulating windows or other noise-insulating features sufficient to maintain interior sound levels at 45 decibels or below in consideration of existing environmental noise levels at the site. The applicant shall submit an analysis of existing noise levels and documentation of the sound insulating capabilities of windows or other noise-insulating features as part of the permit application; and B. A permanently installed air cooling system and a balanced ventilation system, which may be combined. The ventilation system shall filter any outdoor air supply through filters rated MERV 13 or higher as determined by the American Society of Heating, Refrigerating, and Air Conditioning Engineers (ASHRAE). The air cooling and ventilation systems shall be indicated on the plan. (Ord. 127376 , § 23, 2025.)
Source: Seattle Municipal Code (Municode library)URL: https://library.municode.com/wa/seattle/codes/municipal_codeFetched: 7/25/2026