Gas tankless water heater replacement cost in Seattle, WA
Installed, About 180,000–199,000 BTU (2–3+ bathrooms)
A typical tankless water heater (About 180,000–199,000 BTU (2–3+ bathrooms)) costs about $3,100 installed in the Seattle area, 11% above the national figure, because plumbers here earn a median $46 an hour against $31 nationally.
Prices by size in Seattle
| Size | Low | Typical | High | National typical |
|---|---|---|---|---|
| About 150,000 BTU (1–2 bathrooms) | $2,150 | $2,900 | $4,000 | $2,650 |
| About 180,000–199,000 BTU (2–3+ bathrooms) | $2,650 | $3,100 | $4,400 | $2,800 |
Local labor: what plumbers earn here
| Hourly wage | Seattle metro | United States |
|---|---|---|
| 25th percentile | $30 | $24 |
| Median | $46 | $31 |
| 75th percentile | $61 | $41 |
The Seattle market
Seattle splits permits between two agencies. The Seattle Department of Construction and Inspections (SDCI) requires a permit for any furnace replacement or alteration and a refrigeration permit for any split-system heat pump or air conditioner. Plumbing and gas permits come from Public Health Seattle and King County, and no page found says whether a straight water heater replacement needs one, so check with Public Health. Homeowners may pull furnace and plumbing permits, but refrigeration permits go only to licensed refrigeration contractors. HVAC jobs need a cover inspection and a final inspection. Fees for these items were not confirmed. Many homes were built without air conditioning: EIA found only 53% of Washington homes use any AC, while 62% heat water with electricity. Tacoma, Bellevue and King County suburbs issue their own permits.
Since most Seattle homes heat water with electricity, a gas tankless install may mean running a new gas line. An electric tankless model needs a large dedicated circuit and possibly a service upgrade. Ask whether a heat pump water heater would fit the space instead. Winter water arrives cold, so ask what flow rate a tankless unit holds then, and get any gas or electrical work itemized.
Permits in Seattle
| Permit for this job | Unclear (plumbing/gas permits in Seattle are issued by Public Health - Seattle & King County; no page found that states replacement itself needs a permit) |
|---|---|
| Fee | Unclear for these items. Context: PHSKC plumbing/gas permits issued on/after Jan 1, 2025 use a $132 base fee plus $26 per fixture (water heater counting not stated); SDCI 2026 base hourly rate $292/hr with 6.5% inflationary increase to most fees. |
| Who can pull it | Furnace/mechanical STFI: homeowner or contractor; refrigeration (heat pump/AC): licensed refrigeration contractor only; plumbing: homeowner permit or registered contractor via PHSKC |
| Inspection | Yes (HVAC: cover inspection and final inspection) |
Rebates in Washington
HEAR: announced, not open yet. HOMES: announced, not open yet. Source: Washington State Department of Commerce, Energy Division, checked October 13, 2026.
- Washington State HEAR (Climate Commitment Act): State-funded rebates via ~40 local administrators for heat pumps, HPWH, induction, panels; households <=150% AMI ($39.3M recently awarded)
What these programs cover, and other states
Other systems in Seattle
- Gas tank water heater
- Gas furnace
- Central air conditioner
- Heat pump (ducted, outdoor unit + air handler)
Gas tankless water heater cost in other metros
Sources
- SDCI: Furnace and heat pump permit infographic
- Public Health Seattle and King County: plumbing and gas piping permits
- King County: Installing a new water heater
- SDCI Building Connections: changes to plumbing and gas permit fees
- Washington Commerce: state HEAR program
- Washington Commerce: IRA home energy rebates
- EIA, 2020 RECS: Highlights for space heating in U.S. homes by state
- EIA, 2020 RECS: Highlights for water heating in U.S. homes by state
- EIA, 2020 RECS: Highlights for air conditioning in U.S. homes by state
- https://seattle.gov/documents/Departments/SDCI/Codes/2026FeeSummary.pdf
- BLS OEWS May 2025, Seattle-Tacoma-Bellevue, WA (47-2152 plumbers)
- DOE Gas-fired Instantaneous Water Heaters Final Rule TSD (Dec 2024), Table 8.2.6 (2023$)