Two things changed for manufactured home insurance in California this year, and they pull in opposite directions. In January, a new law made the state insurer of last resort cover manufactured homes on the same terms as any other house. In October, that same insurer raises rates by about twenty nine percent on average.
Here is what both changes mean for you, whether the home is your main house or an ADU in the backyard.
The good news: full replacement cost is finally available
For years, manufactured homes in California were insured against what the owner paid for the home, not what it would cost to rebuild it. If the home burned, the check often did not come close to covering a replacement.
Senate Bill 525 fixed that. It became Chapter 476, Statutes of 2025, and took effect January 1, 2026. The law requires the California FAIR Plan to cover manufactured homes and mobilehomes on the same terms as every other home it insures. That opens the door to full replacement cost coverage.
Before this law, no insurance company in California offered it on a manufactured home. More than 500,000 homes were affected. The FAIR Plan also raised its maximum dwelling coverage to three million dollars on the same date.
This matters more on an ADU than most people expect. The cost to replace an ADU is not the price you paid for the unit. It is the unit plus the permits, the foundation, the utility connections, the crane set, and the finish work. A policy written against a purchase price leaves all of that uncovered.
The bad news: rates go up October 15
The California Department of Insurance approved an average rate increase of twenty nine point one percent for the FAIR Plan. It takes effect October 15, 2026 on new and renewal policies. The FAIR Plan had asked for thirty five point eight percent.
An average hides a lot. Homes with heavy wildfire exposure will see much bigger jumps, and some owners will actually see a decrease. Where your property sits on the fire hazard maps matters more than the headline number.
One thing to know before you rely on it: the FAIR Plan is a floor, not a full homeowners policy. It covers fire, lightning, and internal explosion. It does not cover liability, theft, or water damage. Owners who use it normally add a separate Difference in Conditions policy to fill those gaps. Treat the FAIR Plan as the backup you use when no private carrier will write you, not as your first stop.
Manufactured or modular changes the rules
Which product goes on your lot decides which rules apply. People mix these two up constantly.
| Manufactured | Modular | |
|---|---|---|
| Code | Federal HUD Code, run in California by HCD | California Building Code, Title 24 |
| Foundation | Permanent or non permanent | Conventional permanent foundation |
| Height, historically | Single story | Two or more stories |
| Cost and speed | Lower cost, factory speed | Higher cost, more customization |
Here is the part that trips up buyers and even some lenders: a manufactured home on a permanent foundation is still a HUD code manufactured home. It does not turn into a modular or a site built house. The foundation changes how the home is titled and taxed. It does not change which building code governs it.
Fire rules follow the same split. For manufactured homes, HCD sets the ignition resistant construction rules, and those state rules override local ones. Modular and site built homes follow the new California Wildland Urban Interface Code, Title 24 Part 7, which replaced Chapter 7A of the building code on January 1, 2026.
What actually decides your rate happens on your lot
Putting the home on an approved permanent foundation and recording HCD Form 433A converts it from personal property to real property. That is the switch that matters. It moves the home onto real property taxes, opens normal mortgage financing instead of chattel loans, and it is the status lenders, title companies, and insurers all look at.
BuiltADU does not manufacture these homes. Our factory partners do, including Cavco, Silvercrest, Clayton, and Samara. We are the operator on the lot: permits, site prep, the foundation, utilities, the crane set, the recorded 433A, and the finish work. Most of what an insurer looks at is site work, not factory work, and site work is the part we control.
If you are a developer or own multifamily, insurability is now a site selection question, not a closing detail. Price the carrier question before you tie up land in a mapped hazard area, whether you are adding detached units under SB 1211 or building small lot product under SB 1123.
One thing to watch: Zone 0 is not statewide law yet
You will read a lot of confident claims about Zone 0, the ember resistant zone in the first five feet around a house. Be careful with those.
AB 3074, Chapter 259, Statutes of 2020, told the State Board of Forestry and Fire Protection to write the rules for that zone. The deadline has moved several times since, most recently under Executive Order N-18-25. The Board has published draft language and taken comment, but there is still no enforceable statewide Zone 0 rule on the books.
Cities can move first, and some have. San Diego adopted its own version by Ordinance O-22042, effective February 28, 2026. So plan and site the home as though Zone 0 is coming, because it is, but check your own city rather than trusting a statewide date you read online.
Worth saying plainly: BuiltADU does not sell insurance and is not a broker. Nothing here is a quote or a promise of what you will pay. Talk to a licensed broker about your specific address.
Bottom line
Manufactured homes in California can finally be insured like any other house. That is a real win after years of owners being underinsured without knowing it. It arrived the same year the backup insurer got a lot more expensive.
The answer is not to wait for rates to fall. It is to build and site the home so a private carrier will write it, and to get the foundation, the 433A, and the fire details right the first time. If you want to know what your lot can support, call BuiltADU at 714-353-1360 or start a project inquiry. You can size a budget on the Project Cost Calculator.