Where a manufactured home can go: zoning in five cities

Why the federal change doesn’t settle zoning

The HUD code governs how a manufactured home is built. Where it goes is state and local law.

Section 301 of the 21st Century ROAD to Housing Act rewrote the federal definition of a manufactured home to cover one built with or without a permanent chassis. The federal construction and safety standards preempt state and local standards that cover the same aspects of performance and are not identical to them. Installation, site and land-use rules can still apply.

The Act also requires each state to certify to HUD that its laws treat chassis-free homes like homes on a chassis, in financing, title, insurance, manufacture, sale, taxes, transportation, installation and any other areas HUD sets with its consensus committee. The list doesn’t name zoning. The state-by-state deadlines and the rest of the chassis change are covered separately.

San Jose and San Francisco: state law sets the floor

California requires every city to allow manufactured homes where it allows single-family houses.

Under Government Code 65852.3, every city and county, including a charter city such as San Jose or San Francisco, must allow a federally certified manufactured home on a foundation system on a lot zoned for a conventional single-family house. Apart from architectural requirements, the home and its lot get the same development standards as a site-built house on that lot, and those standards may not have the effect of keeping manufactured homes out as permanent residences.

• Design rules: on the home itself, limited to roof overhang, roofing material and siding material. Roofing and siding rules can be no stricter than for a house on the same lot.
• Age: a city may refuse a home made more than 10 years before the permit application.
• Historic places: a city may exempt places listed on the National Register of Historic Places.

The statute protects homes certified under the federal standards, the same definition Section 301 widened. Because it ties to that certification rather than to a chassis, nothing in its text turns on whether the home has one.

Denver: no outright exclusion, but no parity guarantee

Colorado bars cities from excluding HUD-code homes. Its 2025 parity rule covers a different kind of factory-built home.

SB25-002, signed May 8, 2025, amended C.R.S. 31-23-301(5)(b). No municipality may have zoning, subdivision or other development rules that “exclude or have the effect of excluding” state-certified factory-built structures or manufactured homes certified by HUD. A city may still apply zoning, aesthetic, foundation, floor-space, setback and similar standards that apply to similar housing or new site-built housing in the same district. In 1997 a federal court read the earlier version of this rule to let cities confine manufactured homes to particular districts, as long as they don’t keep them out of the city (summarized in the Lincoln Institute’s Colorado fact sheet).

The same law added a parity rule: a city “shall not impose more restrictive standards on factory-built structures” than on site-built homes in the same residential zones, covering home size, sections, floor space, foundations, setbacks and side yards. But Colorado’s definition of a factory-built structure excludes homes built to the federal standard. On the statute’s text, the parity rule reaches state-certified modular homes, not HUD-code manufactured homes with or without a chassis.

Denver’s zoning code defines a manufactured home to include any unit built to the federal standard, alongside chassis-built dwellings, older mobile homes and tiny homes. Its use rules define a single-unit dwelling as one dwelling unit in a single structure, and say mobile homes, recreational vehicles and trailers may not be used as accessory dwelling units (Section 11.8.2.1). In December 2024 Denver created a Manufactured Home Community zone district for its five existing mobile home parks, which had been nonconforming in every district; new communities can’t use it.

Philadelphia: no separate category, and no state rule

Philadelphia's zoning doesn't single out manufactured homes, and Pennsylvania's planning law doesn't reach the city.

Pennsylvania’s Municipalities Planning Code Section 604(4) says zoning ordinances “shall be designed” to provide for “all basic forms of housing,” including mobile homes and mobile home parks. But the code governs cities of the second class A and third class, boroughs, townships and most counties. It does not govern Philadelphia, a city of the first class, which zones under its own code.

Philadelphia’s zoning code (Title 14) has no use category for manufactured or mobile homes. Its use tables (Section 14-602) sort homes under Household Living by how many families live on the lot, single-family, two-family or multi-family, not by how the house was built, and the city’s February 2026 zoning quick guide lists no manufactured-home use in any district. The code’s only definition of a manufactured home, Section 14-203(180.2), applies to its flood protection rules and covers a structure “built on a permanent chassis.”

Boston: no state protection, and a definition built on a chassis

Massachusetts lets towns exclude manufactured homes. Boston's own rules regulate homes on a chassis.

Massachusetts has no law that stops a town from keeping manufactured homes out of residential areas. Its zoning act, Chapter 40A, Section 3, mentions them only to let an owner whose home burned live in one on the site for up to 12 months. In Town of Manchester v. Phillips (1962), the state’s highest court held that a town may exclude them from residential areas, and many towns allow them only in parks (Lincoln Institute, Massachusetts fact sheet).

Boston’s zoning code regulates a “mobile home” as its own use and defines it as a dwelling “transportable in one or more sections, built on a permanent chassis, and designed to be used with or without a permanent foundation.” The neighborhood districts use the same definition.

The chassis in local definitions

Section 301 removed the chassis from the federal definition. Some local definitions still turn on it.

Boston’s definition of a mobile home and Philadelphia’s floodplain definition of a manufactured home both describe a structure built on a permanent chassis, the federal definition before Section 301. Read literally, a home built to the federal standard without a chassis falls outside both. Neither city has said how it will classify one, and no chassis-free home can be sold as an ordinary product until HUD writes the standards for them.

Denver’s definition already covers homes built to the federal standard whether or not they have a chassis, and California’s statute turns on federal certification rather than a chassis. The question there is the one every manufactured home faces: whether the state rule reaches the city, and what the district allows.

Questions

Sources

1. U.S. Government Publishing Office, “Public Law 119-101, Section 301”
2. Legal Information Institute, “42 U.S.C. 5403, construction and safety standards and preemption (as amended)”
3. California Legislative Information, “Government Code 65852.3”
4. Colorado General Assembly, “SB25-002, signed act (amending C.R.S. 30-28-115 and 31-23-301)”
5. Public.Law, “C.R.S. 24-32-3302, definitions”
6. City and County of Denver, “Denver Zoning Code, Article 11, Use Limitations and Definitions”
7. City and County of Denver, “Denver Zoning Code, Article 13, Rules of Measurement and Definitions”
8. City and County of Denver, “Manufactured Home Communities text amendment”
9. Pennsylvania General Assembly, “Municipalities Planning Code (Act 247 of 1968), Section 604”
10. American Legal Publishing, “The Philadelphia Code, Title 14, Zoning and Planning”
11. City of Philadelphia, “Zoning Quick Reference Guide, February 2026”
12. Massachusetts Legislature, “General Laws, Chapter 40A, Section 3”
13. Boston Planning Department, “Boston Zoning Code, Article 2, Definitions”
14. Lincoln Institute of Land Policy, “2026 Manufactured Housing Legal Factsheet: Colorado”
15. Lincoln Institute of Land Policy, “2026 Manufactured Housing Legal Factsheet: Massachusetts”

More on the law: The ROAD to Housing Act explained · Environmental review changes · CDBG and HOME changes · Opportunity Zones · The Innovation Fund · Innovation Fund reforms, city by city · The Build Now Act · Manufactured housing and the chassis rule · Chassis-free manufactured homes by state · RESIDE Act funding status · How RESIDE grants should be sized · The ban on large investors buying homes