Short definition
An electric water heater is a storage-tank water heater that uses one or two immersion resistance elements (typically 4,500 W at 240 V) to heat water. It’s the most common water-heater type in WA homes — simpler to install than gas, slower to recover, and increasingly being replaced by heat pump water heaters during retrofit.
What it is
A standard residential electric water heater is a glass-lined steel tank, 30 to 80 gallons, with two heating elements threaded into the side: an upper element near the top and a lower element near the bottom. Each element has its own thermostat. Only one element runs at a time — the upper has priority and keeps hot water available at the outlet, while the lower handles bulk heating when there’s enough cool water in the tank to demand it.
A 4,500-watt element on 240 V draws 18.75 amps and requires a 30-amp double-pole breaker on 10-gauge copper wire under NEC 422. Above the upper thermostat sits the ECO (high-limit safety) that cuts power if the tank gets dangerously hot.
Recovery is slower than gas — about 20 gallons per hour at a 90°F rise versus 35–40 gph for a gas heater of similar capacity. That’s why electric tanks often run a size larger (50-gallon vs. 40-gallon) for the same household.
WA new construction has shifted heavily toward electric since 2020, both because of electrification trends and because gas-line costs have risen. The most efficient electric replacement on the market — the heat pump water heater — uses about a quarter of the energy of a resistance tank.
Why it matters to a homeowner
If your house has a tank water heater and there’s no flue running up through the roof, you have an electric. The most useful things to know:
- Two elements, two thermostats, one safety. When you have no hot water, the diagnostic ladder starts at the ECO (red reset button), then the upper thermostat, then the lower element. Most no-hot-water calls are solved at one of those three points for under $300 in parts and labor.
- Anode rod determines tank life. Skip anode inspection at year 5 and the tank usually fails by year 9. Inspect and replace the anode and you can hit the full 12-year warranty.
- Replacing in WA needs a permit. Almost every WA AHJ requires a permit for water-heater replacement, which triggers verification of seismic strapping, T&P discharge, expansion tank (if closed system), and drain pan (if installed where leakage matters).
- Heat pump water heater is the rebate-eligible upgrade. PSE, Seattle City Light, Tacoma Power, and Snohomish PUD all offer $700–$1,600 rebates on qualifying HPWH installs as of 2026. Federal IRA tax credit adds 30% up to $2,000.
When a plumber’s quote on a failed electric heater says “$2,500 for direct replacement” without mentioning HPWH, ask about it — the long-term operating cost difference is $250–$450/year.
When you’ll encounter this term
- A failure quote arrives and you’re comparing direct replacement vs. heat-pump upgrade.
- A pre-purchase inspection report flags an electric heater older than 10 years with no anode service record.
- A permit application asks you to identify “water heater type.”
- A WA utility rebate application requires “current heater is electric resistance.”
Common variants and what an electric water heater is not
- Electric resistance vs. heat pump water heater. A resistance tank uses elements only. An HPWH adds a heat pump on top of the tank that pulls heat from the surrounding air — typically 60–70% cheaper to operate but more expensive to install.
- Electric tank vs. electric tankless (whole-house). Whole-house electric tankless requires 200–300 amp service to run two showers — rare in residential WA. Most “electric water heater” in WA = tank.
- One element vs. two element. Almost all 30-gallon-plus residential heaters are two-element. Smaller point-of-use heaters (under-sink 1–4 gallon) are single-element.
Common failure modes
- Lower element failure. Most common. Scale buildup overheats the coil; element burns out. Symptom: lukewarm hot water, cold-shower complaints.
- Upper element failure. Total no-hot-water (because the lower element never gets a chance to fire).
- Upper thermostat sticks closed. ECO trips. Reset; if it trips again, replace the thermostat.
- Anode fully consumed. Tank starts rusting. Eventually leaks (5–15 years).
- Dip tube disintegrates. Lukewarm hot water with white plastic flakes in faucet aerators (mostly affects 1990s-era heaters).
Washington note
WA-specific install and code points:
- Two seismic straps required. WAC 51-56 §507.2 requires straps on the upper third and lower third of the tank, anchored to wall studs. This is one of the most common WA inspection failures on owner-installed heaters.
- 120°F preset cap. RCW 19.27A.060 requires new heaters to be preset at 120°F or the lowest available setting if 120 isn’t reachable.
- Expansion tank often required. If your home has a PRV or a meter check valve creating a closed system (extremely common in Puget Sound), an expansion tank is required.
- Drain pan if leakage matters. Above-living-space installs need a pan plumbed to a drain.
- WSEC favors HPWH. The 2024-cycle WA Energy Code makes resistance-electric harder to use as the compliance path in new construction; HPWH is the default.
Operating cost in WA at 2026 rates (about $0.13/kWh average across PSE, SCL, Tacoma Power, Snohomish PUD): roughly $400–$700/year for a typical 50-gallon resistance electric serving a household of three to four. An HPWH replacement runs $80–$200/year for the same demand.
FAQ
How long does an electric water heater last in Washington?
Typical lifespan is 10–15 years on Cedar/Tolt soft-water Seattle (anode lasts longer, less scale) and 8–12 years on harder Eastside or Spokane water. The single biggest variable is whether the anode rod was inspected and replaced at year 5–7. Heaters with no anode service rarely make it past year 10.
Do I need a permit to replace an electric water heater in WA?
In nearly every WA jurisdiction, yes. Seattle, King County, Pierce County, Snohomish County, Spokane, and Bellevue all require a plumbing permit for water-heater replacement. The permit triggers inspection of seismic strapping, T&P discharge, expansion tank, and drain pan. Same-day permits and 48-hour inspections are common.
Should I replace my electric water heater with a heat pump?
If your existing tank failed and you have at least 700 cubic feet of unconfined air space around the install (garage, large utility room, basement) and an outdoor or vented condensate path, yes — the operating cost savings ($250–$450/year) plus utility rebate ($700–$1,600) plus federal tax credit (30% up to $2,000) often makes HPWH cheaper net than direct resistance replacement. In a small closet, the math is harder.