Mobile Home Permits in California
What needs a permit, who issues it, and how it works, in plain English. Based on the state's own rules.
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The short answer
- Work on the home itself (plumbing, electrical, walls, floors, siding, most windows) is permitted by the state (HCD), not your city. That's true in a park or on private land.
- Patio covers, porches, carports and garages in a mobile home park need a park construction permit from the park's enforcement agency. That's HCD in most parks, and the city or county in a few.
- The same structures on a private lot go through your city or county building department.
- Your park's approval is a separate step. We handle both.
Who issues which permit
| Type of work | Home in a park | Home on a private lot |
|---|---|---|
| Kitchen, bath, plumbing, electrical, walls, floors, siding, windows | HCD (form MH 415) | HCD (form MH 415) |
| Awnings, patio covers, porches, carports, garages | Park's enforcement agency (HCD or local) | City or county building department |
| Foundations, installation and site work | Park's enforcement agency | City or county building department |
HCD puts it plainly: it "has sole authority for permit issuance and inspections of alterations" to manufactured homes and mobilehomes (HCD Information Bulletin 2024-04, December 23, 2024). An owner, or a contractor acting for them, applies on form HCD MH 415 before work begins, and several types of work can go on one application.
Does my project need a permit?
These are common remodeling jobs from HCD's own Manufactured Home Alterations and Permit Guidelines (HCD MH 604). For anything not listed, ask us or the HCD area office.
| Project | Permit? | Notes |
|---|---|---|
| Remodel a bathroom: install or move a tub, shower, sink or toilet | Yes | Any new or modified drain, waste, vent or water piping needs a permit and plan review. |
| Swap a toilet, sink or lavatory in the same spot | No | Unless the drain or water supply piping is modified. |
| Repair joists or replace floor framing | Yes | Plan review required. |
| Patch subfloor (decking) damage | No | Only when the repair is under four square feet. |
| Remove or change a wall | Yes | Load-bearing and shear walls also need engineered plans. |
| New interior wall paneling | Yes | Must have a flame-spread rating of 200 or less. |
| New exterior siding | Yes | A perimeter support detail is required. |
| Replace windows (same size) | Yes | No permit when swapping single-pane for dual-pane in the same opening. |
| Replace an exterior door (same size) | No | A different size needs a permit. |
| Add a ceiling fan or new circuit | Yes | New circuits may need electrical load calculations. |
| Replace a switch, outlet or breaker (same type) | No | |
| Replace a water heater | Yes | Even like-for-like, gas or electric. |
| Re-roof (old roof removed) | Yes | At least two inspections. Liquid roof coatings are not included. |
| Awning, porch or garage attached at a home in a park | Yes | Park construction permit from the park's enforcement agency (HCD or local). |
| Awning, porch or garage on a private lot | Yes | Permit from the city or county building department. |
How the process works
- Scope the work. We look at the home and decide exactly what's being changed: plumbing, electrical, structure, or an attached structure.
- Apply. We file HCD MH 415 for work on the home, plus a park construction or local building permit for any attached structure. Some jobs need plan review, engineered plans or electrical load calculations.
- Get park approval. We confirm colors, materials, setbacks and work hours with park management.
- Build and inspect. Inspectors check the work. Some jobs, like a re-roof, need at least two inspections.
- Final sign-off. The permit is finaled, and you keep the paperwork with the home's records.
Parks with local enforcement near us
Most parks in our service area are enforced by HCD. In these cities, the city (or county) enforces the Mobilehome Parks Act instead, so park construction permits come from them:
- Sebastopol
- San Pablo
- Union City
- Daly City
- Folsom
- Unincorporated Moss Beach (San Mateo County Environmental Health)
Enforcement can change. We confirm the right agency for your specific park before any work starts.
Permit questions
Who issues permits to remodel a mobile home in California?
The California Department of Housing and Community Development (HCD). Under the Manufactured Housing Act, HCD has sole authority to permit and inspect alterations to manufactured homes and mobilehomes, using form HCD MH 415. That's true in a mobile home park and on private land.
Does my city issue the permit for a mobile home kitchen or bathroom remodel?
No. Plumbing, electrical and structural changes to the home itself go through HCD, not the city. The city or county only gets involved for things like foundations, site work and accessory structures on private lots.
Who permits a patio cover or carport in a mobile home park?
The park's enforcement agency issues a park construction permit. In most California parks that's HCD, but some cities and counties enforce the Mobilehome Parks Act themselves. In our area, that includes Folsom, Sebastopol, San Pablo, Union City and Daly City.
Do I need a permit to replace my windows?
Usually, yes. HCD requires a permit for window replacements, even the same size. The exception is swapping a single-pane window for a dual-pane window in the same opening, which doesn't need one.
Do I still need permission from my park?
Often, yes. Park approval is separate from the permit. Many parks have rules on exterior colors, materials, setbacks and work hours. We coordinate with park management as part of every job.
Can you pull the permit for me?
Yes. As a C-47 licensed manufactured housing contractor (License #845399), we prepare and submit the permit application, schedule inspections and handle any plan review.
Sources
- HCD Information Bulletin 2024-04: Manufactured Housing Permit Requirements, Alterations or Conversions (Dec. 23, 2024)
- HCD MH 604: Manufactured Home Alterations and Permit Guidelines (Rev. 12/24)
- HCD: Modifying a Mobilehome (forms MH 415 and MH 604)
Want us to handle the permits?
We pull HCD, park and city permits as part of every project. Call for a free estimate.