Washington: Rules by state

Washington home-sale alarm rules are split between a smoke-alarm statute, a carbon-monoxide statute, and the state seller disclosure form. In the official sources I found, the state requires seller compliance and disclosure, but I did not find a separate statewide pre-closing smoke/CO certificate form for ordinary home sales. ([apps.leg.wa.gov](https://apps.leg.wa.gov/rcw/default.aspx?cite=43.44.110))

Checked against official sources on October 4, 2026. Rules and links change; confirm with the office listed before you act.

Official resources in Washington

RCW 43.44.110 — Smoke detection devices in dwelling units

Washington's smoke-device sale rule, penalties, and who may enforce after a fire. ([apps.leg.wa.gov](https://apps.leg.wa.gov/rcw/default.aspx?cite=43.44.110))

RCW 19.27.530 — Carbon monoxide alarms

Washington's carbon-monoxide sale rule for owner-occupied single-family residences and the tenant maintenance rule. ([apps.leg.wa.gov](https://apps.leg.wa.gov/rcw/default.aspx?cite=19.27.530))

WAC 51-51-0315 — Residential Code section R315, carbon monoxide alarms

Shows required CO alarm locations and when code inspections occur during permit-triggering work. ([app.leg.wa.gov](https://app.leg.wa.gov/wAC/default.aspx?cite=51-51-0315))

RCW 64.06.020 — Seller disclosure statement form

The statewide disclosure form asks whether the property has carbon monoxide alarms and smoke detection devices. ([app.leg.wa.gov](https://app.leg.wa.gov/RCW/default.aspx?cite=64.06.020.&pdf=true))

Washington State Patrol — Home Smoke and Carbon Monoxide Alarms

Current State Fire Marshal guidance on testing, placement, and replacement timing. ([wsp.wa.gov](https://wsp.wa.gov/home-smoke-and-carbon-monoxide-alarms/))

Key facts for Washington

For a dwelling sold on or after July 1, 2019, if it lacks at least one smoke detection device, the seller must provide one before occupancy after sale. ([apps.leg.wa.gov](https://apps.leg.wa.gov/rcw/default.aspx?cite=43.44.110))
For an owner-occupied single-family residence sold on or after July 26, 2009, the seller must equip CO alarms before the buyer may legally occupy. ([apps.leg.wa.gov](https://apps.leg.wa.gov/rcw/default.aspx?cite=19.27.530))
CO alarms must be outside each sleeping area and on each level; add one in a bedroom if it has a fuel-burning appliance. ([app.leg.wa.gov](https://app.leg.wa.gov/wAC/default.aspx?cite=51-51-0315))
Smoke-alarm interconnection is not required when repairs are done solely as a condition of sale and interconnection was not already present. ([apps.leg.wa.gov](https://apps.leg.wa.gov/rcw/default.aspx?cite=43.44.110))
The statewide seller disclosure form asks yes/no/don't know for CO alarms and smoke devices; I found no separate statewide transfer certificate form on these official pages. ([app.leg.wa.gov](https://app.leg.wa.gov/RCW/default.aspx?cite=64.06.020.&pdf=true))
I found no statewide fire-extinguisher rule for ordinary home sale/transfer in these cited sources; extinguisher rules I found were for licensed care settings, not standard home sales. ([app.leg.wa.gov](https://app.leg.wa.gov/wac/default.aspx?cite=110-148-1465&utm_source=openai))

What to do next

Before closing, confirm at least one smoke device is installed and that CO alarms are placed per code near sleeping areas and on each level. ([apps.leg.wa.gov](https://apps.leg.wa.gov/rcw/default.aspx?cite=43.44.110))
Complete the state seller disclosure carefully and keep photos, model numbers, and receipts showing alarms were present before buyer occupancy. ([app.leg.wa.gov](https://app.leg.wa.gov/RCW/default.aspx?cite=64.06.020.&pdf=true))
If your city or county has its own resale inspection program, ask the local fire or building department; I did not find a statewide certificate requirement in the sources above. ([apps.leg.wa.gov](https://apps.leg.wa.gov/rcw/default.aspx?cite=43.44.110))

Helpful guides

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