Local guide / Kennewick, WA
Replacing a Water Heater in Kennewick: Permits and Code Basics
A water heater swap looks simple: old tank out, new tank in. In Kennewick it usually comes with a permit and a short list of code items the inspector will look for.
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Photo: Columbia River, Kennewick, Washington by Ken Lund, CC BY-SA 2.0
Yes, Kennewick issues permits for this
The City of Kennewick publishes monthly Building Permit Activity Reports, and water heater swaps show up in them as residential plumbing permits. The February 2021 report, for example, lists plumbing permits to replace an electric water heater and to replace a water heater at another home, each with its own permit number.
If you are not sure whether your job needs one, ask before the work starts. Building Safety is at 210 W 6th Avenue and can be reached at 509-585-4561.
What the City asks for on the application
Permits are applied for online through the City's Customer Self Service portal. The residential mechanical and plumbing checklist says the plumbing application asks for:
- The number of units being replaced or installed.
- Applicant, owner and contractor names and contact details.
- A valuation. If the owner is doing the work, the City says to double the cost of materials.
If a contractor is doing it, you will also need their City of Kennewick business license number and their Washington L&I contractor license number, both with expiration dates. The City lists 509-585-4266 for help with online applications.
Water heater leaking or out in Kennewick? Call to reach a local plumber.
Call (509) 286-1592Code items an inspector looks for
MyBuildingPermit.com, a permitting site run by a group of Washington cities, has a water heater tip sheet based on the 2021 Uniform Plumbing Code with Washington amendments. Kennewick's inspector has the final word, but these are the usual items.
- Seismic straps. At least 3/4 inch by 22 gauge metal, one in the upper third and one in the lower third of the tank, with the lower strap at least 4 inches above the controls. Plumber's tape does not count.
- Expansion tank. Required on a closed plumbing system. Ask your plumber or the inspector whether yours is one.
- Relief valve line. A 3/4 inch temperature and pressure relief line sloped to drain to an approved location.
- Shutoff valve. A shutoff on the incoming cold water line, plus a shutoff and sediment trap on the gas line for gas units.
- Garage installs. The ignition source has to be at least 18 inches above the floor unless the unit is listed as flammable vapor ignition resistant.
- Insulation. At least R-3 on water piping in unconditioned spaces, and R-10 under an electric water heater sitting on a concrete floor or in an unconditioned space.
Gas to heat pump, and the new home rule
You may have heard Washington requires heat pump water heaters now. The tip sheet explains that rule applies to new construction, starting July 1, 2023. In an existing home, other types of water heaters can be replaced like-in-kind as long as the new unit's rated capacity is not greater than the old one.
So if your gas tank dies, you can generally put in a new gas tank. If you want to switch to a heat pump unit, that is your choice, and it may change the electrical and space needs of the job.
The electrical side
Electrical permits in Washington are covered by L&I rules.
L&I's permit basics page says most electrical work needs a permit, but it lists like-in-kind replacement of one household appliance among the exemptions. A straight swap of an electric water heater on the same circuit can fall under that. A new circuit, a bigger breaker, or new wiring for a heat pump unit is different work, so check with L&I before it starts. L&I also says whoever does the electrical work is the one who has to get the permit.
Before you sign off on the job
A quick checklist for when the new heater is in: straps at the right heights, an expansion tank if your system needs one, a relief line that runs where it should, and a permit number on the paperwork. Keep the invoice and permit together. They are handy if you sell the house or file a warranty claim.
If your old tank is leaking or you have no hot water, call to reach a local Kennewick plumber who can handle the replacement and the permit.
Sources
Where these facts come from
Checked 2026-10-31. Rules and phone numbers change, so confirm with the source before you rely on them.
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