Water Heater Replacement

Replacing a water heater requires at least one permit. The type of permit(s) required depends on what type of water heater is being installed and the scope of any related work that is occurring. 

STEP 1 - Determine what kind of permit is required

When a gas water heater is being installed to replace an existing water heater: 

  • A Mechanical Permit is required. Additionally... 
  • A Plumbing Permit is required when water piping must be rearranged to accommodate the new water heater. 
  • A Building Permit is required if any walls, floors or ceilings are being demolished, constructed, or opened in order to reroute water piping or accommodate the new water heater. 

When an electric water heater is being installed to replace an existing water heater: 

  • A Plumbing Permit is required. Additionally... 
  • A Mechanical Permit is required when existing gas lines that served a previous gas water heater are being removed or capped. 
  • A Building Permit is required if any walls, floors or ceilings are being demolished, constructed, or opened in order to reroute water piping or accommodate the new water heater. 
  • An Electrical Permit is required if the electric water heater is replacing an existing gas water heater.

STEP 2 - Determine whether plan review is required or not

If the water heater is being installed inside a single family residence (whether detached or attached to one other residence) or inside a townhouse unit, plan review is not required for a mechanical, plumbing or electrical permit, and should qualify for Over-the-Counter permitting.

If a building permit is required, then plan review is required. Plan review for a water heater replacement may qualify for Express Review. 

Whether or not plan review is required, all work performed must comply with current codes and will need to be inspected - see Step 4.

STEP 3 - Apply for a building permit

When applying for a permit that requires plan review:

  • Provide a floor plan, showing the area where the water heater is to be located, and indicate any walls that are being demolished or constructed. Label any adjacent rooms.
  • Any structural modifications and framing members must be identified on the plans (headers, posts, shear walls, etc.).
  • If any of the floor, ceiling, or wall assemblies being opened require insulation (to separate heated from unheated space), insulation shall be provided in accordance with the Washington State Energy Code and shall be indicated on the plans.
  • If any of the floor, ceiling, or wall assemblies being opened require fire protection (such as with garage/dwelling separation), fire-rated construction shall be provided and indicated on the plans.
  • Other building permit application requirements can be found on the Building Permit Checklist.

Apply for a permit

STEP 4 - After permit issuance

See Construction Tip Sheet 7 for a summary of code requirements for water heater installation. 

  • Schedule an inspection within 48 hours of water heater installation. 
  • If a contractor does the installation, the contractor should schedule the inspection. If the home owner does the installation, the home owner should schedule the inspection. 
  • The inspection can be scheduled by phone (see instructions on the permit) or can be scheduled online through MyBuildingPermit.com. 
  • See the Mechanical Final and Plumbing Final Inspection Checklists for more information about what the inspectors will be looking for.
  • Keep the manufacturer's installation instructions on site, attached to the water heater if possible.
  • Ensure that bonding wires are maintained or fully reconnected after water heater installation.
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