An accessory dwelling unit (ADU) is a self-contained second home — with its own kitchen, bathroom, and sleeping area — on the same lot as a primary residence. ADUs include backyard cottages, tiny homes, garage conversions, in-law suites, and casitas.

It depends on your state's law, your local zoning district, and your lot. Enter your address and we check official public records — your parcel, your zoning where available, and the actual state and local rules that apply — in seconds, free.

Yes. The address screening is free, instant, and requires no signup. The full report — detailed rules, constraints, cost context, and financing options — is also free in exchange for your contact info.

Every US state gets a cited state-law answer. Parcel-level screening is live in 19 states: Arizona (Tucson, zone-level rules), New Hampshire (town-verified rules), Massachusetts, Florida, plus Arkansas, Connecticut, Indiana, Maine, Maryland, Montana, New Jersey, New York, North Carolina, Ohio, Utah, Vermont, Washington, West Virginia, and Wisconsin. Deeper local rules roll out market by market as builders join the network.

Official public sources: state statutes, municipal ordinances (cited to the section), county GIS and state parcel records, and FEMA flood data — not scraped listings or guesses. Every rule in our database carries its source citation, and rules that have passed our human review carry a green Human Verified tag.

It varies by state. New Hampshire and Massachusetts have state laws that entitle homeowners to an ADU with limited local discretion. Florida leaves the decision to each city and county. Arizona requires larger cities to allow them. Our screener applies the right hierarchy for your address.

Yes. NH RSA 674:71-73, as amended by HB 577 in 2025, entitles owners of single-family homes to an accessory dwelling unit. Towns keep limited discretion over dimensions and process, which is why town-level rules still matter.

Where a town ordinance conflicts with state law, state law generally wins — but towns retain some dimensional discretion, and many posted ordinances still contain overridden language. Our screener flags exactly these conflicts for your town.

It depends on the town. Some towns allow ADUs by right; others use special exceptions or conditional use permits. Enter your address to see your town's current permit path.

Yes — statewide. Since February 2025, the Affordable Homes Act makes one ADU up to 900 sq ft (or half the principal home's floor area) a by-right use in single-family zoning districts across Massachusetts.

Towns can apply reasonable regulations (site plan review, dimensional standards) but cannot prohibit a by-right ADU or impose owner-occupancy requirements under the 2024 state law.

The state by-right protection covers ADUs up to 900 sq ft or half the principal dwelling's gross floor area, whichever is smaller. Larger units may still be allowed under local zoning.

It depends on your city or county. Florida state law authorizes — but does not require — local governments to allow ADUs. Many cities allow them; some counties prohibit them in single-family districts. Enter your address to check your parcel.

No. SB 48, which would have required every local government to allow ADUs by December 2026, passed the Senate 38-0 but died in the House on the last day of the 2026 session. Some websites report it as law — that is incorrect. The proposal is expected to return in 2027.

Yes — Florida's ADU statute does not override HOA covenants or deed restrictions. Even where zoning allows an ADU, private restrictions can still apply.

Yes. Most Tucson residential zones (R-1, R-2, R-3, CR-1 and others) allow an ADU, attached or detached, with size caps between 1,000 and 1,500 sq ft depending on the zone. Enter your address and we'll check your exact zone.

In R-1/R-2/R-3 zones, up to 1,000 sq ft (capped at 75% of the primary residence's square footage). In CR-1, GR-1, SR and similar zones, up to 1,500 sq ft (capped at 70%). Some zones use a percentage-of-lot formula.

In many zones, yes — Arizona HB 2720 allows two ADUs, and the HB 2721 Middle Housing Initiative can allow up to four total structures on qualifying lots. Zone-specific limits apply.