Water heater repair and installation in Seattle: costs and code points

What does water heater repair or replacement cost?

The ranges below are national figures from two cost guides. They differ because each guide uses its own data, which is a good reminder to compare several written quotes.

HomeAdvisor lists some common repair parts with labor: a pressure relief valve at $20 to $200, an anode rod at $50 to $150 and electric heating element replacement at $200 to $300. It puts a tank flush at about $200.

Should you repair or replace?

HomeGuide puts the average life of a tank water heater at 8 to 12 years, up to about 15 with maintenance, and a tankless unit at 15 to 20 years. As a rule of thumb:

• Repair makes sense for a younger unit with a single failed part: a thermocouple, a gas control valve, a heating element, a relief valve or an anode rod.
• Replace when the tank itself leaks, the unit is near the end of its expected life, or repairs keep adding up. A leaking tank cannot be patched.
• Act quickly if you smell gas near the heater. Leave and call 911 and Puget Sound Energy, as described in our emergency checklist.

What does Seattle require for a water heater installation?

In Seattle, plumbing permits and inspections come from Public Health Seattle and King County, which says codes require a permit whenever you install, relocate or change a plumbing or gas piping system. Its water heater guidance lists the points an inspector will look at:

• Seismic bracing. The tank must be strapped against earthquakes with two 20-gauge sheet metal straps, one in the upper third and one in the lower third of the tank.
• Access. The heater must sit in an accessible location with at least 24 inches of continuous width for access.
• Garage protection. A heater in a garage must be protected by a fixed barrier, such as a metal post set in the concrete, between the heater and where a car parks.
• Expansion tank. On a closed water system, an expansion tank or other approved thermal expansion device is required.
• Relief valve discharge. The temperature and pressure relief valve must drain by gravity to the outside or to an approved drain.
• Gas units. Gas heaters need enough combustion air and correct venting, because poor venting can cause dangerous carbon monoxide. Only direct-vent units may go in a bedroom or bathroom unless special criteria are met, and any new or changed gas piping needs a separate gas piping permit.

Outside Seattle, Clyde Hill and unincorporated King County, the permit comes from your city's building department. Our location pages list them.

Tank, tankless or heat pump?

Tank heaters are the lowest-cost option to install. Tankless heaters cost more up front but last longer, according to HomeGuide's lifespan figures. Heat pump water heaters move heat from the surrounding air into the tank. Seattle City Light says they are 2 to 3 times more energy-efficient than conventional water heaters and can cut water heating energy use by up to 70 percent. City Light currently advertises a $750 rebate on heat pump water heaters, which can be passed through as an instant discount when a contractor buys a qualifying unit from a participating distributor, or claimed by do-it-yourself buyers. Check the City Light page for current terms before you rely on it.

How do you choose a water heater installer?

• Look up the company in the L&I verify tool. Water heaters are part of the plumbing trade that L&I says requires a certified plumber, so paid installation should be done by a licensed plumbing contractor.
• Ask whether the quote includes the permit, seismic straps, an expansion tank if needed, haul-away of the old unit and any venting or electrical changes.
• For a heat pump unit, ask whether the contractor can apply the City Light discount on the invoice.
• Get several written quotes. City Light itself recommends at least three bids for heat pump water heater projects.

We are an independent guide and do not do this work. You can send a request through our contact page; we reply with next steps and, where we know a licensed contractor for your area, an introduction.