Replacing a water heater in Western Washington typically costs $1,800–$4,500 installed for a standard tank, and $4,500–$9,000+ for a tankless conversion. Where you land in that range depends on five things: fuel type, capacity, code upgrades your old install is missing, access, and whether you’re switching styles. Here’s how the number actually gets built.
The quick answer by type
| Type | Unit cost | Installed total (wet side) | Typical lifespan |
|---|---|---|---|
| 40–50 gal tank, electric | $500–$1,200 | $1,800–$3,000 | 10–15 years |
| 40–50 gal tank, gas | $600–$1,500 | $2,000–$3,500 | 8–12 years |
| Tankless, gas (whole home) | $1,200–$2,800 | $4,500–$9,000 | 20+ years |
| Heat pump / hybrid | $1,700–$3,500 | $3,500–$6,500 (before rebates) | 12–15 years |
Prices reflect what licensed wet-side plumbers actually quote, not national averages — Seattle-area labor runs meaningfully above the national norm.
Why the installed price doubles the unit price
The tank at the hardware store is $700. The quote says $2,800. The difference is rarely padding — it’s usually these line items:
- Code upgrades. Washington requires seismic strapping, a proper TPR discharge line, and (for newer installs) expansion tanks on closed systems. If your old heater predates these requirements, your new install must meet them.
- Permit. Most wet-side jurisdictions require a plumbing permit for water heater replacement — typically $50–$250. A plumber who says you don’t need one is a red flag, not a bargain.
- Disposal and haul-away of the old unit.
- Gas or electrical work. Upsizing a gas line for tankless, or adding a 240V circuit for heat pump units, adds $500–$2,000.
- Location problems. Crawl-space, attic, or tight-closet installs take longer and cost more.
Tank vs. tankless on the wet side
Tankless wins on lifespan and endless hot water; tank wins on upfront cost and simplicity. Two wet-side-specific factors worth knowing:
- Our incoming water is cold — groundwater in Western Washington runs 45–50°F much of the year. Tankless units must be sized for that temperature rise; an undersized unit that worked fine in California will disappoint here.
- Heat pump water heaters are heavily incentivized in Washington right now, with utility rebates and federal credits that can bring a hybrid’s net cost close to a standard tank’s. If your heater lives in a garage or large utility room, run this option before defaulting to like-for-like.
Repair or replace?
A rule of thumb that holds up: if the tank itself leaks, replace — tanks aren’t repairable. If it’s the thermostat, element, gas valve, or anode ($150–$600 fixes) and the unit is under 8 years old, repair usually pencils. Past 10 years, put repair money toward replacement.
Watch for: water pooling at the base, rust-colored hot water, rumbling sounds (sediment), or a pilot that won’t stay lit. Pooling water at the tank base means the clock has already run out.
How to get a fair quote
- Get two or three quotes and make sure each lists permit, code upgrades, and haul-away explicitly.
- Confirm the plumber is licensed, bonded, and insured — check their contractor number at lni.wa.gov.
- Ask what the quote assumes about your existing venting, gas line, and shut-off valves — surprises live there.
- For tankless conversions, ask specifically how the unit is sized for 45°F incoming water.