Washington Department of Ecology Wood Stove Emissions Rules

Why this matters

Washington State has the strictest wood-burning appliance rules in the United States. WAC 173-433 (Solid Fuel Burning Devices) sets emission limits below the federal EPA 2020 NSPS for new installations, requires resale disclosure on uncertified stoves, and authorizes county-level burn bans during stagnant air events. A sweep working in Washington needs to advise the homeowner on three separate things: whether a particular stove can be legally installed today, whether an existing stove must be removed at home sale, and what to do during a stage 1 or stage 2 burn ban. Getting any of these wrong creates legal exposure for the homeowner and reputational damage for the sweep. This article maps the WAC rules, the King County and Puget Sound Clean Air Agency overlays, and the field workflow.

What WAC 173-433 actually limits

WAC 173-433-100 sets a particulate emission limit for new solid fuel burning devices sold and installed in Washington that is stricter than the federal EPA 2020 NSPS. Specifically:

• Federal EPA 2020 NSPS (40 CFR 60 Subpart AAA Step 2): 2.0 g/hr particulate for cordwood stoves measured by Method 28 (catalytic) or 2.5 g/hr (non-catalytic, cordwood)
• WAC 173-433-100: 4.5 g/hr particulate maximum for non-catalytic, 2.5 g/hr for catalytic, measured by Method 28

The federal Step 2 standard is stricter than the historic WAC number, so today most EPA 2020 certified stoves meet the WAC. The rare case where a stove was certified under an older test method but still currently sold can fail the WAC even when EPA-listed. Always cross-check the test method on the certification label.

Pellet stoves are exempt from the cordwood limit but must meet a separate WAC pellet stove standard.

Resale disclosure for uncertified stoves

WAC 173-433-100(3) and RCW 70A.15.3580 require that solid fuel burning devices installed prior to 1992 (and not bearing the WA DOE or EPA certification label) must be removed and destroyed at the time of property sale. The seller cannot leave an uncertified stove in place for the buyer.

The chimney sweep is often the first person the seller calls when the home inspector flags the stove. The sweep walks the resale checklist:

• Confirm the certification label is missing or shows pre-1992
• Confirm the stove is non-pellet (pellet stoves have different rules)
• Quote the removal (the seller is responsible) and recycling through a metal scrap vendor
• Provide a destruction certificate from the scrap vendor to the seller for closing documents

A masonry fireplace (open hearth) is exempt from the resale rule because it is not a "solid fuel burning device" within the WAC definition. A masonry heater (a Russian-style masonry mass heater) is exempt by the same exclusion.

County and air-agency overlays

Several Washington counties have stricter local rules through their Clean Air Agencies:

• Puget Sound Clean Air Agency (PSCAA), covering King, Kitsap, Pierce, and Snohomish counties
• Northwest Clean Air Agency (Skagit, Whatcom, Island)
• Spokane Regional Clean Air Agency
• Yakima Regional Clean Air Agency

Each agency runs burn-ban rules independent of the state. PSCAA has the most aggressive enforcement: during a Stage 1 burn ban, only EPA-certified or pellet appliances may operate, and only as a primary heat source. During a Stage 2 ban, no wood burning is allowed except in the rare "no other adequate source of heat" exemption (typically off-grid homes).

The sweep advises homeowners to sign up for PSCAA Air Alert notifications via pscleanair.gov so they know when a ban is active.

Installation - new stove rules

For a new install in Washington:

• The stove must be on the WA Department of Ecology certified list (a subset of the EPA-certified list)
• Installation must comply with the manufacturer's listing and NFPA 211 clearances
• A building permit is required in most jurisdictions; the local AHJ sets the threshold
• Spokane County, Pierce County, and Pierce Conservation District operate stove-changeout rebate programs; check before quoting

The DOE certified list lives at ecology.wa.gov. The list is regenerated quarterly as new stoves clear the WA test verification process. A stove that is EPA-certified but not on the WA list cannot be installed in WA new construction; it can be installed in a replacement-only context in some counties.

Resale workflow for the sweep

The seller's home inspection flags an old stove. The sweep visit:

1. Inspect the stove and confirm certification status by reading the back label
2. Photograph the label or its absence; record the make, model, serial number
3. Write a removal proposal that itemizes: stove removal, chimney cap, flue inspection for relining decision, hearth restoration if applicable
4. Coordinate the recycling drop-off; obtain destruction certificate
5. Provide the seller a "Stove Removal Compliance Letter" referencing RCW 70A.15.3580 for the closing file

The seller takes the destruction certificate and compliance letter to the title company. Closing proceeds.

Replacement stove options

If the seller or buyer wants to retain wood-burning capability:

• Replace with a WA DOE certified EPA 2020 stove from the current ecology.wa.gov list
• Install a pellet stove (subject to pellet stove emissions rule, but generally accepted)
• Install a gas log set or gas stove (no emissions rule applies to gas)
• Convert to a heat pump (eligible for Washington State Clean Buildings rebates)

Common WA DOE listed cordwood stoves (verify current list):

• Pacific Energy Super 27 LE, Alderlea T4 LE, T5 LE
• Lopi Endeavor NexGen, Cape Cod
• Hearthstone Manchester, Heritage
• Regency F1500, F2500
• Jotul F45 Greenville, F500 Oslo

Pellet stove rules

WAC 173-433-100(2) sets a separate pellet stove particulate limit and requires WA DOE certification for new pellet stove installs. Pellet stoves are exempt from Stage 1 burn bans but not Stage 2 bans in most PSCAA counties.

References

1. WAC 173-433 (Washington Administrative Code), Solid Fuel Burning Devices.
2. RCW 70A.15.3580 (Revised Code of Washington), Solid Fuel Burning Device Standards.
3. Washington Department of Ecology, Certified Solid Fuel Burning Devices List at ecology.wa.gov.
4. Puget Sound Clean Air Agency Regulation III, Article 13: Solid Fuel Burning Devices, available from pscleanair.gov.
5. 40 CFR Part 60 Subpart AAA, EPA NSPS for New Residential Wood Heaters (2020 Step 2 federal standard).
6. NFPA 211 (current edition), Standard for Chimneys, Fireplaces, Vents, and Solid Fuel-Burning Appliances.