Storage tank
$1,600–$2,400Typical cost, including installation
WATER HEATER REPLACEMENT IN MERCER ISLAND
Mercer Island, WA Water Heater
Replacement
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MERCER ISLAND AT A GLANCE
Replacing a water heater in Mercer Island.
Mercer Island charges a flat $120 for a water heater exchange permit when no new gas piping is added (2026 schedule). The city issues its own electrical permits. Puget Sound Energy supplies electricity and gas. City water from Seattle's Cedar River supply is very soft, about 1.5 grains per gallon.
- Permit to replace with the same type
- Yes · City of Mercer Island Community Planning & Development (Permit Counter)
- Permit fee
- $120 for a Water Heater Exchange with no new gas piping (2026 Fee Schedule, 2nd revision, effective August 1, 2026).
- Who gets the permit
- Licensed plumbing contractors apply online. The city's plumbing permit page describes a separate email application for some permit types when the applicant isn't a licensed contractor.
- Electric utility
- Puget Sound Energy
- Gas utility
- Puget Sound Energy
- Water
- City of Mercer Island water utility, supplied by Seattle Public Utilities (primarily Cedar River water, with the South Fork Tolt as an alternate) · About 1.55 grains per gallon (about 24 mg/L calcium hardness) in SPU's Cedar distribution system, May 2026 quarterly analysis; the city's 2025 report does not list hardness.
- Rebate worth checking
- PSE heat pump water heater rebate (Active)
- Typical home
- Built 1973 (median) · 67% owner-occupied
- Companies found
- 11 that advertise water heater work
01 / TYPICAL PRICES
What a new water heater costs.
Know before you call.
Heat-pump tank
$2,500–$5,000Typical cost, including installation
Tankless
$2,400–$5,400Typical cost, including installation
AI equipment illustrations; models vary and images are not to scale. Typical national prices from Home Depot ↗, checked September 28, 2026. The source doesn’t say how many jobs the ranges are based on. These are not Mercer Island averages or guaranteed quotes.
Compare what each quote includes.Equipment · Labor · Permits · Old heater removalHow to compare quotes →
What we know about prices in Mercer Island
- National installer’s published rangeThe ranges above. Home Depot ↗
- Local permit fee$120 for a Water Heater Exchange with no new gas piping (2026 Fee Schedule, 2nd revision, effective August 1, 2026).. City of Mercer Island Community Planning & Development (Permit Counter) fee source ↗
- Local company’s advertised price2 of the companies listed for Mercer Island post water heater prices or specials on their websites: Bee's Plumbing & Heating, Harts Plumbers, Electricians, & HVAC Technicians. Each offer has its own conditions.
- Measured local dataNot collected yet, so no Mercer Island average is shown.
What can change the price in Mercer Island?
Adding new gas piping means the $120 flat fee no longer applies. Other stand-alone trade permits cost at least $214, or the total of issuance, plan review and unit fees. Mercer Island issues its own electrical permits (it's on L&I's list), so the city permits a new circuit for a heat pump water heater.
02 / COMPANIES WE FOUND
Who replaces water heaters in Mercer Island?
Companies that advertise water heater replacement here, with what their water heater customers say.
Companies we found in our research. They are not Ember & Tank providers or partners. We show selected reviews, not a rating or every review. How we choose reviews →
Bee's Plumbing & Heating
Lists Mercer Island among the areas it serves. Based in Seattle.
- Tank
- Tankless
- Repair
- Emergency service
Published price: Coupon: '$500-$800 OFF Water Heater Installation' ($500 off tank, $800 off tankless; not valid on dispatch fee; expires 9/30/2026). No base installed prices published.
What the reviews say
Water heater feedback Reviewers praised same-day response, clear explanation of options and quick tank and tankless installs.
Worth knowing Reviewers on BBB and Yelp said water heater prices were far above other quotes or not itemized (the company said on BBB it later sent an itemized invoice and wanted to make it right).
5 water heater reviews read, checked September 30, 2026.
Brennan Heating & Air Conditioning
Lists Mercer Island among the areas it serves. Based in Seattle.
- Tank
- Tankless
- Heat pump
- Repair
- Emergency service
What the reviews say
Water heater feedback No water heater-specific praise was found in the sources checked.
Worth knowing A BBB complainant said a gas tank was installed facing the wrong way, blocking access to controls (Brennan apologized and scheduled a return visit to rotate it), and Yelp reviewers described a delayed Costco-sourced install and a later diagnosis they disputed.
3 water heater reviews read, checked September 30, 2026.
Fast Water Heater Co. (Washington)
Lists Mercer Island among the areas it serves. Based in Woodinville.
- Tank
- Tankless
- Heat pump
- Repair
- Emergency service
What the reviews say
Water heater feedback Reviewers praised punctual, communicative technicians, quick scheduling and a competitively priced replacement.
Worth knowing BBB complainants and a Yelp reviewer said code items were sold as add-ons after a basic quote and that installs failed inspection or permits lingered; the company says it walks customers through a signed code checklist, and in several cases refunded charges or did the code work free.
5 water heater reviews read, checked September 30, 2026.
Fischer Plumbing
Lists Mercer Island among the areas it serves. Based in Mountlake Terrace.
- Tank
- Tankless
- Heat pump
- Repair
- Emergency service
What the reviews say
Water heater feedback Reviewers praised easy scheduling, same-day replacement and prices they described as fair.
Worth knowing A BBB complainant said a 2021 water heater install never kept water hot and tripped the breaker (Fischer said it provides a 1-year parts and labor warranty and cannot be responsible for home electrical; it refunded a service call fee), and a 2009 Yelp reviewer said the installer tried to raise a $900 quote to over $1,500.
4 water heater reviews read, checked September 30, 2026.
Goldstar Plumbing
Lists Mercer Island among the areas it serves. Based in Seattle.
- Tank
- Tankless
- Heat pump
- Repair
- Emergency service
What the reviews say
Water heater feedback Testimonials praised heat pump water heater installs with clear options, permit and inspection handling, cleanup and haul-away.
Worth knowing No water heater complaints found in the sources checked.
2 water heater reviews read, checked September 30, 2026.
Green Planet Plumbing & Sewer
Lists Mercer Island among the areas it serves. Based in Seattle.
- Tank
- Tankless
- Heat pump
- Repair
- Emergency service
What the reviews say
Water heater feedback A customer praised a next-day estimate, quick scheduling and pleasant technicians for a hot water tank replacement.
Worth knowing No water heater complaints found in the sources checked.
1 water heater review read, checked September 30, 2026.
Harts Plumbers, Electricians, & HVAC Technicians
Lists Mercer Island among the areas it serves. Based in Tacoma.
- Tank
- Tankless
- Heat pump
- Repair
- Emergency service
Published price: Promos (no base price): $100 off a standard water heater (or $39/month financing); $250 off a tankless water heater (or $199/month financing); 5% Heroes Discount up to $200.
What the reviews say
Water heater feedback Yelp reviewers praised technicians who flushed water heaters and explained maintenance clearly.
Worth knowing BBB reviewers and complainants said technicians recommended whole-house repipes or new tanks for water heater problems that other plumbers fixed cheaply (Harts denied any fraudulent practice and offered manager follow-up), and one disputed $2,500 for a tankless flush and diagnosis that did not fix the issue.
5 water heater reviews read, checked September 30, 2026.
Hunt's Services
Lists Mercer Island among the areas it serves. Based in Milton.
- Tank
- Tankless
- Heat pump
- Repair
- Emergency service
What the reviews say
Water heater feedback Reviewers praised same-day emergency water heater replacements and a technician who also corrected code issues at a reasonable price.
Worth knowing BBB reviewers said a tankless flush ended in a paid replacement without the promised phone controller (Hunt's said a controller is typically an optional upgrade) and that a $10,000 boiler hot water tank replacement left them without hot water.
5 water heater reviews read, checked September 30, 2026.
Puget Sound Plumbing & Heating
Lists Mercer Island among the areas it serves. Based in Burien.
- Tank
- Tankless
- Heat pump
- Repair
- Emergency service
What the reviews say
Water heater feedback Reviewers praised fast response to a leaking water heater, fair pricing and dispatch updates on arrival times.
Worth knowing No water heater complaints found in the sources checked.
3 water heater reviews read, checked September 30, 2026.
Ben's Plumbing, Heating & Air
Lists Mercer Island among the areas it serves. Based in Seattle.
- Tank
- Tankless
- Repair
- Emergency service
What the reviews say
We haven’t found reviews that mention this company’s water heater work yet.
Also listing Mercer Island: Home Comfort Alliance.
Order: companies based in Mercer Island first, then companies whose water heater reviews we’ve read. Each group is alphabetical. These businesses are not our employees or vetted partners and do not receive requests from Ember & Tank. We haven’t checked their license, insurance or quality of work. L&I Verify a Contractor, Tradesperson or Business ↗.
FROM COMPANIES SERVING MERCER ISLAND
Photos of water heater jobs from these companies.
HOMES IN MERCER ISLAND
What Mercer Island homes are like.
1973Median year built
61%Built before 1980
67%Owner-occupied
58%Heat with utility gas
67%Single-family homes
About 61% of homes were built before 1980. Older homes often have older venting, smaller closets and shutoff valves that should be checked before install day.
58% of homes heat with utility gas, so gas water heaters with existing venting are common here.
U.S. Census Bureau, American Community Survey ACS 2024 5-year ↗ (2020-2024). Heating fuel is what homes use to heat the house. It often, but not always, matches the water heater’s fuel.
LOCAL CONDITIONS
What’s different in Mercer Island.
A flat fee to swap a water heater
Mercer Island charges $120 for a straight water heater swap with no new gas piping. Other stand-alone trade permits have a $214 minimum.
Very soft Cedar River water
The island buys its water from SPU, mostly from the Cedar River. It tested at about 1.5 grains per gallon in May 2026, so very little scale builds up in tanks.
ENERGY & WATER
Who supplies Mercer Island homes.
Energy
- Electric: Puget Sound Energy (PSE's electric area covers King County outside Seattle, Mercer Island included)
- Gas: Puget Sound Energy
Water
City of Mercer Island water utility, supplied by Seattle Public Utilities (primarily Cedar River water, with the South Fork Tolt as an alternate): About 1.55 grains per gallon (about 24 mg/L calcium hardness) in SPU's Cedar distribution system, May 2026 quarterly analysis; the city's 2025 report does not list hardness.
Mercer Island 2025 Water Quality Report ↗ · SPU Quarterly Surface Water Analysis (May 20, 2026) ↗
REBATES & CREDITS
Rebates for Mercer Island homes.
For Puget Sound Energy customers in Mercer Island. Ask installers for the price before rebates, then check with the program that you qualify.
- PSE heat pump water heater rebate ↗Active$1,000 back on a qualifying Tier 3 or Tier 4 heat pump water heater installed on or after January 1, 2026.
- Washington HEAR (Home Electrification and Appliance Rebates) ↗ActiveState-run program covering heat pump water heaters, heat pumps, induction cooking and electrical upgrades for households at or below 150% of Area Median Income.
- IRA Home Energy Rebates (HARP appliance rebates and HOMES) ↗Not launchedThe federally funded appliance (HARP) and whole-house (HOMES) rebates for households up to 150% AMI had not launched statewide.
- Federal Energy Efficient Home Improvement Credit (25C) ↗EndedCovered improvements made through December 31, 2025.
Checked September 30, 2026. Who qualifies and the conditions: Washington rebates · How to check an incentive.
PERMITS & LICENSING
Permits and licenses in Mercer Island.
Permits and who issues them
Mercer Island's fee schedule has its own "Water Heater Exchange (no new gas piping)" permit, which is an exception to its $214 minimum for trade permits. You get most single-family plumbing permits online at MyBuildingPermit.com.
City of Mercer Island Community Planning & Development (Permit Counter) ↗ · Mercer Island 2026 Fee Schedule (2nd revised, effective Aug 1, 2026) ↗ · Mercer Island Single Family Residential Plumbing Permits ↗ · L&I: cities that do their own electrical permits and inspections ↗
Check the installer’s license
Ask for the license number and search it yourself on the L&I Verify a Contractor, Tradesperson or Business ↗. A listing on Ember & Tank is not a license check. Washington licensing explained →
NEARBY CITIES
Compare places near Mercer Island.
| City | Distance | Permit to replace | Fee | Electric |
|---|---|---|---|---|
| Newcastle | 4 mi | Required | $80 | Puget Sound Energy |
| Bellevue | 4 mi | Required | $50 | Puget Sound Energy |
| Renton | 6 mi | Required | $69 | Puget Sound Energy, Seattle City Light |
| Tukwila | 6 mi | Required | $37.81 | Seattle City Light, Puget Sound Energy |
| Seattle | 7 mi | Required | $137 | Seattle City Light |
| Burien | 8 mi | Required | $98 | Seattle City Light, Puget Sound Energy |
COMMON QUESTIONS
Mercer Island water heater questions.
How much is a water heater permit on Mercer Island?
$120 for a water heater exchange with no new gas piping, under the 2026 fee schedule (revised August 1, 2026).
Where do I apply?
Most single-family plumbing permits are online at MyBuildingPermit.com. The Permit Counter's number is 206-275-7605.
More guides: Washington water heater replacement · All local guides