Do you need an HVAC permit in Washington?
By Mario Bailey Last checked
- Always required
- 7
- of 8 jurisdictions
- Conditional
- 1
- depends on size or scope
- Not required
- 0
- exempt outright
HVAC Permit rules nationwide, beyond Washington.
Requirements and size thresholds for HVAC permits vary by locality. The table below compares what each Washington county or city requires. Always confirm with the local office before starting.
Comparing states? See HVAC permit rules across every locality we cover.
What to know about HVAC permits in Washington
HVAC permits in Virginia typically apply to new installations and to replacing gas or oil fueled equipment. Costs vary with equipment type and your locality. Using a licensed mechanical contractor matters, because the install must meet code and pass inspection, which also helps protect your equipment warranty.
The application steps and inspection sequence for HVAC permits come from the model code rather than from Washington law, so they read the same wherever you build. We keep that walkthrough in one place: how an HVAC permit application and its inspections work, start to finish. What changes between Washington jurisdictions is below: who requires a permit, what they charge, and which office you file with.
Swipe sideways to see thresholds and confidence.
| Locality | Permit required? | Typical threshold | Confidence |
|---|---|---|---|
| Bellevue | Yes | Not specified | Confirmed on official page |
| Clark County | Yes | Mechanical permits cover installation of heating and cooling equipment such as furnaces, heat pumps, A/C units, ductless mini splits and gas piping; for additions and new construction this work is included in the ADS or NHC permit. | Confirmed on official page |
| King County | Yes | Not specified | From an official source |
| Pierce County | Yes | Not specified | Confirmed on official page |
| Seattle | Yes | Not specified | Confirmed on official page |
| Snohomish County | Yes | Not specified | From an official source |
| Tacoma | Yes | Not specified | Confirmed on official page |
| Thurston County | Conditional | Heating and cooling equipment and gas piping require a Minor Permit, but replacement of electric forced-air heating units and water heaters is exempt. | Confirmed on official page |
| No localities match your filter. | |||
What an HVAC permit costs in Washington
7 Washington jurisdictions we cover publish a fee figure for this work. Each line is quoted from that office's own schedule and linked to its citation. The figures are not comparable to one another: some are flat minimums, some a percentage of job value, some charged per fixture, so what you pay depends on which schedule applies and on your job's valuation.
Flat single-family mechanical inspection fees per Table 8 of Ordinance 6879: furnace up to 100,000 BTU $59, furnace over 100,000 BTU $79, heat pump $59 each, air conditioner $59 each, duct work only $59 per permit, effective 2026-01-01
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Application rev 1.30.23: $94 issuance plus per-appliance fees including furnace or heat pump $29, A/C or evaporative cooler $29, compressor or boiler $89, gas pipe 1-5 $89.
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Mechanical installation-only permit is a flat $183 inspection fee covering up to six furnace, heat pump, AC, boiler or wood stove systems per dwelling unit, with no application review fee and no state surcharge on mechanical permits, per the 2026 single family residential fee guide
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Issue each mechanical permit fee $58.00, plus unit fees per equipment type (for example $17.00 for a furnace up to 100,000 Btu/h) (PCC Table 17C.10-1-E, 2026 fees).
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Ducted HVAC systems are priced by project valuation with a $292 minimum; equipment installed without plans is a flat per-unit fee under Table D-8, for example $60.35 per unit for a furnace, heat pump, or wall heater and $75.50 per unit for a new gas or oil burner, plus a 5% technology fee, per the 2026 Fee Subtitle
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Filed as a Mech/Plbg residential trade permit priced from the PDS valuation table starting at a $45 permit fee plus $29.25 plan check at the lowest valuation bracket, plus a $150 base fee per application, the $6.50 state surcharge and a 3% technology surcharge, per PDS Bulletin 18 effective 3/13/2026
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Standalone HVAC and mechanical permits run 2.81 percent of construction value with a $180 minimum fee, per the PDS Fee Schedule effective 1/1/2025
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Jurisdictions not listed publish no dollar figure we could quote. Absence does not mean a permit is free.
Common questions about HVAC permits in Washington
- Do I need an HVAC permit in Washington?
- In most of Washington, yes. Permits are issued locally, so the answer comes from your Washington city or county rather than a single statewide rule. Of the 8 Washington jurisdictions we have verified for HVAC work, 7 require a permit outright, 1 depends on the size or scope of the job, and 0 require none.
- Is there an HVAC permit exemption in Washington?
- 1 of the 8 Washington jurisdictions we cover sets a threshold rather than a flat rule, so the same job can be exempt in one Washington county and permitted in the next. The table above lists each Washington jurisdiction's published threshold in its own words, with the source and the date we verified it.
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