Remodeling a Bathroom in a Manufactured Home

A bathroom in a manufactured or mobile home is regulated by a different office and a different set of rules from a site-built house. In Washington, the Department of Labor and Industries (L&I) handles permits and inspections for alterations to manufactured and mobile homes, and the work follows the federal manufactured home standard as well as state rules. This page covers what that means for a bathroom remodel, with L&I's fees effective 1 July 2026.

L&I, not the city, issues the permit

L&I says: "Use our Find Labels page to find out if your home is a manufactured or mobile home that requires permits and inspections for alterations by L&I." And: "You must get a permit before starting an alteration." Clark County's plumbing and mechanical permit applications point the same way: "Manufactured/mobile home", contact "WA Dept. of Labor and Industries 360.896.2300".

Electrical is split by location. L&I: "If the electrical work takes place outside your home, you need an electrical permit. If the electrical work takes place inside your home, you need a manufactured/mobile home permit."

Homeowners can "Buy a permit online", with online processing listed as immediate. For "All other alteration applications, allow 2-3 weeks for a response." L&I's contact is 1-800-705-1411, option 3.

Which bathroom work needs an L&I permit

WAC 296-150M-0302 lists alterations and whether each needs a permit and inspection. The bathroom-relevant rows:

The fixture note matters most. The table's footnote says: "Fixtures include: Faucets, sinks, lavatories, laundry tubs, water closets (toilets), tubs, showers and tub/shower combos. A permit is not required for replacement of a like fixture as long as there are no changes to the existing water or drain lines." This is L&I's rule for manufactured homes only. It is not the City of Vancouver's rule for site-built houses, so do not carry it across.

L&I also notes: "Exemption from the permit and inspection requirements shall not be deemed to grant authorization for any work to be done in violation of the applicable code".

Codes for manufactured home alterations

Under WAC 296-150M-0306:

• "Alterations to a manufactured/mobile home must be in compliance with the Manufactured Home Construction and Safety Standards, 24 C.F.R. Part 3280" (the federal HUD standard).
• Water heaters must be "listed by a nationally recognized testing laboratory and installed per the manufacturer's installation instructions".
• "All electrical alterations and additions to the manufactured/mobile home shall comply with the current edition of the National Electrical Code".
• Structural alterations follow the International Residential Code.

Washington's plumbing and electrical rules for site-built homes, described on bathroom plumbing code and bathroom electrical code, are useful background, but your L&I inspector decides what applies to your home.

L&I fees (effective 1 July 2026)

These are from WAC 296-150M-3000, effective 1 July 2026. L&I adjusts them over time, so confirm when you buy the permit.

What to check before you plan

Manufactured homes are built to their own federal standard, so do not assume site-built dimensions or details. Before you choose fixtures or a layout, check:

• The floor: look and feel for soft spots around the toilet, tub and vanity. Repairing or replacing floor decking or joists is a permit row in the L&I table, so it belongs in the plan and the permit, not in a surprise. See rot, mold and leaks found during demolition.
• The tub or shower opening: measure the existing opening and the route into the room before you buy a replacement tub or shower base. If a new unit does not fit without framing changes, those changes may be structural alterations under L&I's rules.
• Where the plumbing runs: find out where the drains and supply lines run before you plan to move a fixture. Adding fixtures or changing water or drain lines takes the job out of the like-fixture exemption.
• Wall depth: check the framing before you plan a recessed niche or medicine cabinet. Adding a wall opening is a permit row.
• Wall and ceiling board: adding gypsum board to walls or ceilings is its own permit row, so tell L&I if the plan includes new board.

Selling or refinancing

Washington's seller disclosure form asks, for manufactured and mobile homes, "If alterations were made, were permits or variances for these alterations obtained?" L&I says: "An HRI is often needed to disclose unpermitted work before you refinance or sell your manufactured or mobile home." HRIs, homeowner requested inspections, "cannot be used to approve alterations" and "are non-refundable once an inspector visits your permit site." More on disclosure is in unpermitted bathroom work.

Who to ask

For permits and inspections, Washington L&I Factory Assembled Structures, 1-800-705-1411, option 3. For whether a plumber or electrician is certified, L&I's Verify tool; see checking contractor and trade credentials. To talk through a bathroom project with JDI Construction, start at our Vancouver bathroom remodeling page.