Guide
Zoning laws by state
Can you put a modular home on your land? Call the right desk, then read HOA covenants. State law is only the first filter.
You cannot put a modular home on every parcel. Zoning, deed restrictions, septic feasibility, and floodplain rules can each kill a project that looked legal on a factory website. This page is the verification script plus a state snapshot. For the civics of variances and districts, see Zoning laws. For climate and plant coverage, see the custom regional guide.
Buyers on r/ManufacturedHome ask the same first question: "Who do I call?" If the land is inside city limits, start with city planning or zoning. If it is unincorporated, start with the county. Ask this sentence: "Are modular homes allowed in this zoning district?" That wording gets you to the right person faster than "Can I put a prefab here?"
The call script
1. Identify the jurisdiction from the tax parcel, not the mailing address. 2. Ask planning whether IRC modular is allowed by right in that district. 3. Ask building whether a permanent foundation and factory insignia satisfy their residential permit. 4. Ask environmental health about perc, well, and septic if you are off municipal systems. 5. Pull recorded CC&Rs and HOA architectural rules from the county clerk. Public zoning does not override private covenants. 6. Get the answer in writing (email is enough) before you order a factory slot.
LegalClarity and county handouts make the same point: even when modular is treated like site-built under the building code, an HOA can still require on-site construction, a minimum roof pitch, or a materials list your plan does not meet.
State snapshot (verify locally)
| State | What to know in 2026-2027 | Who to start with |
|---|---|---|
| Florida | HB 399 (effective January 1, 2027) expands by-right placement of modular and manufactured homes in many single-family districts. Local design standards still apply. | City or county zoning, then HOA |
| California | ADU statutes favor backyard units. Title 24 energy rules kill many Amazon kits. Crane access and trench length decide cost. | City planning plus ADU checklist |
| North Carolina | Appearance standards and special-use permits appear in some towns. Covenant cases have gone both ways on "mobile home" language. | County planning, then recorded covenants |
| Texas | Windstorm (TDI) and WUI rules change wall and roof specs. HUD and IRC are both common. | County or city plus windstorm inspector |
| New York | State code plus local overlays. Some towns still write "trailer" language that staff apply too broadly. | Town building department |
| Colorado | Snow load and wildfire (WUI) drive engineering. ADU and modular both active on the Front Range. | County community development |
| Pennsylvania | Industrialized housing is state-oversight modular. Local zoning still controls the lot. | Local zoning officer plus DCED context |
| Washington | Energy code and wet-site foundations matter. Factory plants serve the I-5 corridor. | City or county permit portal |
This table is a briefing, not a permit. Always re-check the ordinance year you apply.
Florida HB 399 without the hype
HB 399 is the bill buyers keep pasting into forums. It restricts local governments from banning compliant manufactured and modular homes solely because of construction method in certain single-family districts, starting 2027. It does not erase setbacks, floodplain rules, or HOA covenants. Design standards (roof pitch, facade materials) can still apply. If a Florida listing says "HB 399 means you are approved," ask for the zoning letter anyway.
HOA and covenant reality
North Carolina and Tennessee cases show courts sometimes distinguish permanent IRC modular from "mobile homes" in old covenants, and sometimes they do not. The recorded words win. If the covenant bans trailers, temporary structures, or homes not built on site, budget a lawyer before a factory deposit. An HOA architectural committee can also sit on plans for months.
Septic and floodplain are zoning-adjacent vetoes
A failed perc test is a reason to walk from land you do not own yet. Floodplain development permits add elevation, insurance, and foundation cost. Mills County, Iowa and similar rural handouts list the residential building permit, septic, well, and optional floodplain permit as a set. Modular does not skip any of them.
Appearance standards that act like bans
Some towns allow modular by right, then require a 6:12 roof, masonry on the street face, or a minimum width that a single-section plan cannot meet. Those rules are legal in many places. They are not a "prefab ban." They are a design filter. Ask for the residential design guidelines PDF, not just the zoning map.
Width standards show up in agricultural districts too. Iowa-style statutes limit some width mandates on ag land, but your state may not. Bring the statute if you have one. Do not rely on a factory salesperson to quote it.
ADU versus primary dwelling
A backyard ADU and a primary modular home use different statutes. California ADU law is not a statewide permission slip to drop a full-size ranch on a vacant lot. Vacant land usually cannot host an ADU until a legal primary dwelling exists. If your plan is "cheap Amazon unit as the house," you are not in the ADU lane. See Are expandable prefabs legal.
Utility letters
Planning approval without a will-serve letter from the electric cooperative or the sewer district is not a complete yes. Rural co-ops quote long lead times and footage charges. Get the letter dated and in the permit file.
Related tools
Run the zoning checker for a first-pass state note, then confirm with staff. If you are comparing backyard units, use Prefab ADU companies. For a shortlist check, use buyer help.
What by right does not mean
By-right approval means you do not need a rezoning vote if you meet the published standards. You still need a building permit, inspections, and any overlay (historic, coastal, WUI, airport). Staff can still reject a plan that misses setbacks or parking. By-right is a process win, not a skip-the-counter win.
If the clerk says they do not allow trailers, show the IRC insignia language and ask them to cite the ordinance section. If they cite a mobile-home park overlay, that is a different district. Your parcel either is in it or is not.
FAQ
- Can an HOA ban modular homes?
- Yes. HOAs and recorded CC&Rs can restrict factory-built homes even when state or city zoning allows them. Read the covenants before you buy land.
- Does Florida allow modular in all single-family zones?
- HB 399 expands by-right placement beginning 2027, but local design standards, floodplain rules, and private covenants still apply. Get a zoning letter.
- Who do I call to see if modular is allowed?
- City planning if you are inside city limits, county planning if you are not. Ask: "Are modular homes allowed in this zoning district?" Then call building and, if needed, environmental health.
- Is modular always treated like site-built?
- Under the IRC it usually is, once it sits on a permanent foundation. Zoning definitions and covenant language may still use older "mobile home" words. Do not assume staff know the difference until you show the insignia path.
- Can I get a permit for an Amazon expandable as a house?
- Rarely. Those kits often lack HUD or IRC approval and fail energy codes such as California Title 24. See the expandable prefab legality guide.