Shoreline, WA Building Safety: Fire Sprinkler Requirements (2026)
Key Facts
- Mandate
- Sprinklers required in all new one/two-family homes
- Design standard
- IRC Section P2904 adopted
- Addition exception
- No retrofit unless fire-flow rules require it
- Fire alarm tradeoff
- 30% fire-flow reduction with monitored alarm
- Small addition threshold
- Additions of 500 sq ft or less use Section 901.4.8.1
Summary
Every new one- and two-family dwelling built in Shoreline must include an automatic residential fire sprinkler system under SMC § 15.05.040(D), which adopts and amends International Residential Code Section R313.2, though additions to older homes that never had sprinklers are excused unless the fire code's separate fire-flow rules trigger the requirement anyway.
D. Section R313.2 is adopted and amended as follows: R313.2 One- and two-family dwellings automatic fire sprinkler systems. An automatic residential fire sprinkler system shall be installed in one- and two-family dwellings. Exception: An automatic residential fire sprinkler system shall not be required for additions to existing buildings that are not already provided with an automatic residential sprinkler system unless otherwise required under IFC Section 102.5 as amended by SMC § 15.05.050. R313.2.1 Design and installation. (no amendment to language) E. Section P2904, Dwelling Unit Fire Sprinkler Systems, is adopted.
Full Breakdown
SMC § 15.05.040(D) adopts and amends IRC Section R313.2 to require an automatic residential fire sprinkler system in every one- and two-family dwelling built in the City of Shoreline, and separately adopts Section P2904, Dwelling Unit Fire Sprinkler Systems, as the design and installation standard for those systems. The rule carries one exception: an addition to an existing house that was never equipped with a residential sprinkler system does not need one installed retroactively, unless International Fire Code Section 102.5, as amended by SMC § 15.05.050(A), otherwise requires it.
That cross-referenced fire code amendment supplies the trigger: additions of more than 500 square feet that push the finished home's total square footage past the minimum fire flow the IFC's own tables require, and the distance to the nearest hydrant, must install an NFPA 13D sprinkler system, though a 30 percent reduction in the required fire flow is allowed if the home instead installs a monitored residential fire alarm system that is maintained and reported to the fire department. Additions of 500 square feet or less can instead comply with the fire flow provisions in Section 901.4.8.1.
Together, the two sections mean a homeowner adding a modest amount of square footage may avoid a sprinkler retrofit, but a larger addition, or one that outstrips the available hydrant flow, triggers the sprinkler mandate the original house never carried.
Violations & Fines
Building or adding onto a one- or two-family dwelling without the required automatic fire sprinkler system violates SMC § 15.05.040(D) and is enforceable under SMC § 20.30.770: a Class 1 civil infraction under Chapter 7.80 RCW, or, for willful violations, a misdemeanor with a fine up to $1,000 and up to 90 days in jail, with each week of noncompliance a separate offense.
Frequently Asked Questions
Does every new house in Shoreline need fire sprinklers?
If I add onto an older Shoreline home, do I need to add sprinklers?
Can I avoid a sprinkler system by installing a fire alarm instead?
Sources & Official References
Other rules in Shoreline
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Fire Sprinkler Requirements in Nearby Cities
How other cities in King County handle fire sprinkler requirements.