Lynnwood, WA Building Safety: Fire Sprinkler Requirements (2026)

2. 020(A) is the residential trigger: every building built under the International Residential Code with three or more attached dwelling units must be sprinklered, and even a one- or two-family dwelling must have a residential fire sprinkler system if it sits 500 feet or more from a public or private hydrant, counting the length of any panhandle or access tract in that measurement. Subsection (B) sets a separate commercial-scale trigger at 5,000 square feet of fire area or greater regardless of use, and subsections (D) through (H) extend sprinkler requirements to additions, changes of use, and buildings where alterations within a 72-month period exceed 50 percent of the assessed value on file with the Snohomish County assessor's office.

The rule text states that all sprinkler and standpipe systems must be installed per the applicable NFPA standard and the South County Fire (SCF) fire sprinkler standard; SCF, the South Snohomish County Fire & Rescue Regional Fire Authority, provides fire services to Lynnwood by interlocal agreement and its standards are incorporated directly into the city's own installation rule. 060(C) sets sprinkler-head placement rules for exterior balconies, decks and ground-floor patios on R1 and R2 occupancies. 030 requires the owner to post a competent adult fire watch for the first 48 hours, then a licensed and bonded private security company after that, and to notify the fire marshal within eight hours of starting the fire watch.