Short answer: in most big cities, yes, and the map has changed fast. Of the 30 largest U.S. cities we cover, 22 allow an accessory dwelling unit by right on a single-family lot, three allow one only in some districts, two allow one with limits that rule most lots out, Dallas grants one only by special exception on a no-rental deed restriction, and Baltimore and Pittsburgh have not legalized them yet. We read each city's zoning code, its ADU page and its fee schedule and recorded the status, the size cap, the owner-occupancy rule, the number of units a lot may have and the city's own permit-fee example.
Every row links to the city page that quotes the rule, so you can read the source language yourself. The table sorts by any column.
All 30 cities
| City | ADU allowed? | Max detached size | Owner on site? · units per lot | City's own fee example | Rule the city cites, and notes |
|---|---|---|---|---|---|
| Albuquerque, NM | By right | 750 sq ft gross (650 in Downtown CPO-3) | None found in the IDO standards · 1 | about $1,142 in city fees for a 750 sq ft casita ($160 site plan + building + trades), before impact fees | Integrated Development Ordinance 4-3(F)(6) (2025 update, eff. April 2026) Allowed in R-A, R-1, R-T and R-ML since the 2023 zoning change. Behind the rear wall, 5 ft setback, one parking space, facade color similar to the house. A unit carved out inside the house is a two-family dwelling instead. |
| Baltimore, MD | Not yet legal | Bill as introduced: 75% of the house; internal unit 40% (committee amendment) | Not applicable yet · 1 per lot under the pending bill | about $595 in city fees for a 600 sq ft detached unit if priced under the current schedule (no ADU fee line exists) | Zoning Code 9-701 and 15-504 (current); Council Bill 26-0195 (pending); Md. Chapter 197 of 2025 State law required a local ADU law by October 1, 2026; the Council re-referred CB 26-0195 to committee on September 28, 2026. Today only carriage-house conversions and single-family to multi-family conversions in R-7 to R-10 are allowed. |
| Charlotte, NC | By right | 600 sq ft or 70% of the house, whichever is greater, max 1,000 heated | Same ownership as the house; no occupancy rule found · 1 | about $2,136 for a $150,000 detached unit (County valuation permits + $475 City review) | UDO 15.6.F; LUESA Fee Ordinance; City FY2026 IRL schedule Building permits are Mecklenburg County's, zoning is the City's. The City's older declaration form still prints 50%; the current UDO text says 70%. Must share the house's driveway except on corner, through or alley lots. |
| Chicago, IL | Some districts | Not stated on the city page (coach house in the rear yard) | Only in ADU-Allowed RS Areas · 1 coach house; conversion units by a 33% density formula | $2,450 minimum plan-based permit for a coach house; $1,800 for a conversion unit | Ordinance SO2024-0008918 (in force April 1, 2026); DOH pre-certification; Table 14A-12-1204.3 By right in RT, RM, business and C1/C2 districts; single-family RS districts only where the alderperson has opted the area in, with possible owner-occupancy rules and annual block caps. Half of any two or more ADUs must be affordable for 30 years. |
| Cincinnati, OH | By right | Footprint 15% of the lot or 800 sq ft (lots of 4,000 sq ft+); never larger than the house; 25 ft | Yes: owner or designated responsible person, recorded covenant, $15,000 fine · 1 | about $4,095 in permits for a $150,000 new build; $2,937 for a $60,000 conversion | Zoning Code 1421-06 (since 2023-10-02); FY2027 B&I fee schedule Registration with the Zoning Administrator, renewed every odd year. No parking. No tiny homes on wheels. Short-term rental allowed if registered. Electrical permits are Inspection Bureau, Inc.'s. |
| Dallas, TX | Special exception | 25% of the house's floor area in districts such as R-7.5(A) | Rental barred by a required deed restriction · 1 by special exception | about $2,227 for 500 sq ft including the $600 Board of Adjustment fee | Dallas Development Code 51A-4.209(b)(6)(E); Chapter 52 Table A-I Single-family lots are limited to one dwelling unit; the Board of Adjustment may grant an additional dwelling unit only if it will not be rented. A homeowner permit cannot be used to build it. |
| Fort Worth, TX | Major limits | Not stated; no taller than the house; utilities from the house's meters | Not stated; whether a unit may be rented separately in a one-family district could not be verified · not stated | $672.95 building permit for an 800 sq ft guest house, plus trade permits | Zoning Ordinance 5.301 (habitable accessory structure); Fee Ordinance 26-28781 No stand-alone ADU permit: a casita is a habitable accessory structure. The code text sits on a host that refused every request, so the rental question is hedged on the city page. A separate meter needs a $591 variance. Texas SB 673 did not pass. |
| Houston, TX | By right | 900 sq ft (secondary dwelling unit) | No city rule; deed restrictions may · 1 | about $789 for a 900 sq ft unit (square-footage tier + 25% plan review + $33.56 admin) | Code of Ordinances Chapter 42; Residential Permitting 101 Houston has no zoning: the city enforces subdivision deed restrictions, which often bar second units. One added parking space for a unit of 900 sq ft or less. |
| Indianapolis, IN | Some districts | 720 sq ft (secondary dwelling unit) | Yes: owner occupies one unit as permanent residence · 1 | $1,202 for a new detached unit (five flat permits); $865 for a conversion | Zoning Ordinance Table 743-1 and Sec. 743-306; 2026 DBNS fee schedule An accessory use in D-A, D-S, D-1 to D-5II, D-8, MU-2 and MU-3; not in D-6, D-7 or D-9 to D-11, where a variance of use is needed. One added parking space; a unit above an existing garage does not count against accessory-building area. |
| Jacksonville, FL | By right | Footprint 25% of the house or 750 sq ft, whichever is less | Homestead exemption required (or applied for) · not stated | about $528 for 600 sq ft with three inspections; about $920 for 750 sq ft with eight | Zoning Code 656.403(g); Ordinance Code 320.409 Florida Statute 163.31771 permits but does not require ADU ordinances; Jacksonville allows them by its own code. Behind the house, outside required yards; HOA rules must be certified on the application. |
| Kansas City, MO | By right | 800 sq ft or 90% of the house; footprint 60% of the house or 25% of the rear yard | Yes: recorded deed restriction before the certificate of occupancy · 1 | about $1,146 for a $250,000 detached unit; $639 for an $80,000 basement conversion | Zoning Code 88-305-15; IB170 Only on lots whose principal building is a detached house. No added parking. A contractor building a detached accessory building over 400 sq ft needs a city residential building license. |
| Long Beach, CA | By right | 800 sq ft detached by right (16 ft, 18 near transit); attached 50% or 800; conversions uncapped | No (JADU with shared bath excepted) · ADU + JADU | about $5,229 for an 800 sq ft new detached unit; $2,089 for a 400 sq ft garage conversion | Planning Information Bulletin IB-PZ-001 (state law applied directly); Gov. Code 66323 No local ADU ordinance in force. Impact fees waived at 750 sq ft or less; school district charges $5.38 per sq ft above 500. Pre-approved plans can be permitted the same day. Fees changed October 1, 2026. |
| Los Angeles, CA | By right | 1,200 sq ft detached (800 by right at 4 ft setbacks); attached 50% of the house | No (state law bars it) · ADU + junior ADU | about $2,696 permit + plan check on a $150,000 unit; LADBS sample shows $6,227 in school fees on top | Gov. Code 66314 and 66323; LAMC 12.22 A.33; LADBS bulletin P/BC 2026-150 Ministerial, 60-day decision. Impact fees only at 750 sq ft and above; school fees above 500 sq ft. AB 2533 amnesty for units built before 2020. |
| Louisville, KY | By right | 800 sq ft or 30% of the house, whichever is greater | Yes: owner lives in the house or the ADU (relief only by conditional use permit) · 1 | about $573 for a new 800 sq ft detached unit ($50 planning + building, trade and state plumbing permits) | Land Development Code 4.3.27; 815 KAR 20:050 Permitted in R-R, R-E, R-1 to R-5 and U-N. No short-term rental. A conditional use permit ($550) can relieve a standard; staff supported one for an LLC-owned lot in 2026. HOA bans are not overridden. |
| Miami, FL | Some districts | 800 sq ft detached / 500 attached, and 10% of the lot | One ownership; rental only while the property has homestead status · 1 | about $1,772 in permits for a $150,000 600 sq ft unit; city impact fees can add $8,099 | Miami 21 Table 3, 3.18 and Table 13 (Ord. 14375, eff. 2025-10-01); City Code 2-214 By right in T3-L, T3-O and all T4 to T6 zones, not in T3-R. Rental needs a $300 registration and $250 a year. One parking space unless in a TOD or transit corridor. Amnesty program for existing units. |
| Milwaukee, WI | By right | 1,300 sq ft or 16% of the lot, max 1,600; internal/attached 1,000 | Yes: an owner must live in the house when the permit is filed · 1 | about $2,430 for an 800 sq ft detached unit (incl. $450 assessor charge); $1,530 for a basement conversion | MCO 295-505-5-f and Table 295-505-2.5 (eff. 2025-08-02) A limited use in every residential district. Minimum 300 sq ft. The DNS info sheet still prints a flat 1,300 sq ft cap; the code allows more on large lots. Electrical by a licensed electrician only. |
| Minneapolis, MN | By right | 1,300 sq ft or 16% of the lot, max 1,600; internal/attached 800 | Only for an internal ADU (covenant); none for attached or detached since March 2021 · 1 | about $3,536 for a $150,000 detached unit; $2,098 for a $60,000 internal unit (incl. $325 zoning fee) | Zoning Code 550.1420; Table 525-1 No parking minimum or maximum. The ADU cannot become a separate tax parcel. Electrical permits are the state's (DLI). |
| New York, NY | By right | 800 sq ft; 2 stories or 25 ft | Yes: lot must be an owner's primary residence at initial occupancy · 1 | $130 DOB filing for an 800 sq ft cottage (design, plumbing and electrical fees separate) | DOB Ancillary Dwelling Unit page; DCP City of Yes ADU guide; Admin Code Table 28-112.2 Backyard units barred in historic districts, the Special Bay Ridge District and certain low-density R districts outside transit zones; basement and cellar units barred in FEMA and DEP flood-risk areas. No parking requirement. |
| Philadelphia, PA | Major limits | 800 sq ft, inside an existing building only (no new detached units) | Yes: affidavit and deed restriction · 1 | about $533 to $852 for a conversion ($189 zoning + $76 alteration + trades) | Zoning Code 14-604(11); L&I ADU checklist and Quick Guide Only in a historic structure, or a detached or semi-detached house in RSA-5 or CMX-1 on a lot of 1,600 sq ft or more; Council Districts 1, 2, 3 and 7 allow both, 4, 5, 8 and 9 historic only, 6 and 10 none. Bill 250042 to relax the rules was still only introduced as of June 2026. |
| Phoenix, AZ | By right | 1,000 sq ft or 75% of the house (lots to 10,000 sq ft); up to 3,000 on larger lots | No (state law bars it) · 2, a third if affordable on a 1-acre lot | about $2,124 for 600 sq ft; $3,226 for 1,000 sq ft, plus $98 plot plan | ARS 9-461.18 (HB 2720); Zoning Ordinance 706.A.8 as amended 2024 No parking, no design-matching rule. Short-term rental of an ADU is allowed under state law. Free standard plans in review. |
| Pittsburgh, PA | Not yet legal | Under 800 sq ft (overlay rule); the pending bill proposes 1,000 | Yes under the overlay rule (deed restriction) · 1 | about $1,641 for a $150,000 detached unit where an overlay applies (PLI + zoning + ACHD plumbing) | Zoning Code 912.08 (Ord. 32-2018); Council Bill 2025-1545 (held) ADUs are permitted only inside an ADU Overlay District; the city says the 2018 Garfield overlay was set to expire after two years. Bill 2025-1545 (ADUs by right, two per lot, no owner occupancy) was held in Council after a September 2026 hearing. |
| Portland, OR | By right | 800 sq ft or 75% of the house, whichever is less | No (only the optional SDC-waiver covenant) · 2 in R20 to R2.5 | about $36,721 for a new detached ADU with SDCs (city sample), about $17,759 with the SDC waiver; $2,864 for a basement conversion | Zoning Code 33.205; PP&D ADU program SDCs (about $19,000 in the city's sample) are waived for a 10-year no-short-term-rental covenant. No parking. Homeowner may not do the electrical work on an ADU. |
| Sacramento, CA | By right | Detached units may total 1,200 sq ft (local); 800 under state standards | No (state law bars it) · 2 in any combination | about $5,272 at 749 sq ft; $10,624 at 750 sq ft (city estimate CDD-0419) | City Code 17.228.105; Gov. Code 66323; estimate CDD-0419 (rev. July 2026) The 750 sq ft cliff is state law: park, flood and transportation impact fees switch on at 750. Free shelf-ready plans (367, 559, 747 sq ft). Each ADU needs its own address. |
| San Antonio, TX | By right | 800 sq ft or 50% of the house, whichever is larger, max 1,600 | Yes: notarized affidavit and recorded covenant · 1 | $1,136.30 combination permit for 800 sq ft ($1,227 with surcharges) | UDC 35-371; DSD ADU page; FY 2027 Development Fee Schedule By right in R-1 to R-6 and RM-4 to RM-6. An owner who will not live on site must rezone. Fee waivers possible for a unit rented at 80% AMI for 5 years. |
| San Diego, CA | By right | 1,200 sq ft; 800 allowed even over the FAR cap; conversions uncapped | No (JADU only, unless it has its own bathroom) · base ADU + JADU, plus bonus ADUs | about $6,490 for a 500 sq ft detached unit; about $17,236 for 800 sq ft detached | SDMC 141.0302; IB 400; IB 501 Table 501A; Gov. Code 66317 A detached ADU over 500 sq ft pays the full new-dwelling plan check. First two ADUs exempt from Development Impact Fees. No parking outside the Coastal Overlay Zone. Minimum 31-day rentals. |
| San Francisco, CA | By right | 850 sq ft (studio or 1 bed) or 1,000 (2+ beds) detached; conversions uncapped | No (state law bars it; JADU with shared bath excepted) · detached ADU + JADU on a single-family lot | about $10,400 at DBI and Planning for a $125,000 garage conversion; about $20,500 for a $300,000 cottage | Planning Code 207.1 and State ADU program; Gov. Code 66315, 66323, 66332 City fees run 6 to 9% of construction cost. Impact fees waived under 750 sq ft or on lots with three or fewer units. Local program adds ADUs to multi-unit buildings, likely rent controlled. |
| San Jose, CA | By right | 1,000 sq ft (lot to 9,000 sq ft) or 1,200; conversions uncapped | No (cannot be required) · ADU + junior ADU | $12,628 average for a detached unit up to 750 sq ft (city fee estimator); $21,446 at 751 to 1,200 | SJMC 20.80.175 and 20.80.176; Gov. Code 66323 Ministerial, 60 days. Impact fees waived at 750 sq ft or less. Setbacks 0 ft for one story, 4 ft for a second; 18 ft one-story height, 25 ft two-story. |
| Seattle, WA | By right | 1,000 sq ft gross (NR zones), lot of at least 3,200 sq ft | No · 2, including two detached | $3,453 for a 500 sq ft DADU (SDCI's 2026 example); about $5,250 at 1,000 sq ft | SDCI ADU page; Tips 116A/116B; SMC 23.42.022 (2025) No parking. Plumbing is a King County permit and the county sewer capacity charge is billed for 15 years. DADUs barred in shoreline districts. |
| St. Louis, MO | By right | 750 sq ft or 50% of the house, whichever is greater, max 1,200; 25 ft tall | No · 1 | $1,525 building permit on a $150,000 detached unit plus about $350 in trade permits and a $120 Certificate of Inspection | Ordinance 72036 (eff. 2025-09-29); Zoning Code 26.20.021 By right in all residential districts since September 2025; duplex owners may add one. Interior or basement units are reviewed as additional dwelling units instead. No parking for the ADU, but the house's required space may not be removed. |
| Tucson, AZ | By right | 1,000 sq ft or 75% of the house; every lot may have at least 650 | No (state law bars it) · 2, a third if affordable on a 1-acre lot | about $1,850 for a 400 sq ft casita; $3,190 for 1,000 sq ft; $1,740 with a model plan | UDC casita rules (amended 2024-11-21); ARS 9-461.18 Allowed in any zone that permits residential use. No parking, 5 ft rear and side setbacks, height to the zone's single-family limit. Impact fees extra. |
The status is the city page's reading of the zoning code as of the date it was last verified. Size is the cap on a detached unit (attached and conversion rules are in the notes). Owner on site records whether the code requires the owner to live in the house or the ADU. The fee column is the city's own worked example at the size or cost stated, before impact fees, utility charges and design fees unless the cell says otherwise. Download the table as CSV.
What the comparison shows
Legal in 22, conditional in 5, blocked in 3
Albuquerque, Charlotte, Cincinnati, Houston, Jacksonville, Kansas City, Long Beach, Los Angeles, Louisville, Milwaukee, Minneapolis, New York, Phoenix, Portland, Sacramento, San Antonio, San Diego, San Francisco, San Jose, Seattle, St. Louis, Tucson permit an ADU by right. Chicago, Indianapolis, Miami permit one only in some districts: Chicago in its multi-unit, business and commercial districts and in single-family areas an alderperson has opted in; Miami in every transect zone except T3-R; Indianapolis in the D-A to D-5II and D-8 districts but not D-6, D-7 or D-9 to D-11. Fort Worth, Philadelphia allow one with limits that exclude most lots: Philadelphia only inside an existing building in two zoning districts or a historic structure, and only in some Council districts; Fort Worth as a habitable accessory structure whose rental status the city's own code host would not let us verify. Dallas requires a Board of Adjustment special exception and a deed restriction against renting the unit. Baltimore, Pittsburgh have no ADU use in their zoning code today: Baltimore's bill was re-referred to committee four days before the state's October 1, 2026 deadline, and Pittsburgh's code allows ADUs only inside an overlay district that the city says was set to expire in 2020, while a citywide bill is held in Council.
State law decides more than city hall in a third of the table
The six California cities (Los Angeles, San Diego, San Jose, San Francisco, Sacramento, Long Beach) share the same floor: an 800 sq ft detached unit at 4 ft setbacks approved ministerially within 60 days, no owner-occupancy rule, no impact fees under 750 sq ft, and a junior ADU on top. Long Beach has stopped writing its own ordinance and applies the state law directly. Arizona's 2024 law gives Phoenix and Tucson two units per lot, no owner occupancy and, in Phoenix, short-term rentals. Washington's law gives Seattle two units including two detached. Texas has no state law (SB 673 died in 2025), which is why Houston, San Antonio, Dallas and Fort Worth each land somewhere different, and Florida's statute permits but does not require ADU ordinances. Maryland's 2025 law set the deadline Baltimore has now missed.
The 2023 to 2026 wave
Eleven of the 30 cities changed their ADU rules in the last three years: Cincinnati (October 2023), Albuquerque (2023), Phoenix and Tucson (2024), Milwaukee (August 2025), St. Louis and Miami (September and October 2025), New York (City of Yes), Chicago (in force April 2026), Indianapolis (ordinance effective August 2026) and Seattle (2025 code rewrite). Two more have bills pending (Baltimore, Pittsburgh) and Philadelphia has had a relaxation bill sitting since January 2025. Anyone quoting a 2022 summary of ADU rules is wrong in at least a third of these cities.
Nine cities require the owner to live on site, and they enforce it with the deed
New York, San Antonio, Philadelphia, Indianapolis, Milwaukee, Louisville, Kansas City, Pittsburgh (under its overlay rule) and Cincinnati require the owner, or in Cincinnati a designated responsible person, to live in the house or the ADU. Most record the promise: San Antonio a notarized affidavit and county covenant, Philadelphia an affidavit and deed restriction, Kansas City a deed restriction before the certificate of occupancy, Cincinnati a covenant plus registration every odd year with a $15,000 fine for breaking it. Fourteen cities impose no such rule, and in the eight California and Arizona cities state law forbids one. Three cities tie it to something else: Jacksonville and Miami to a homestead exemption, Minneapolis only to internal units created under older rules. Dallas sidesteps the question by barring rental altogether.
Size caps: 720 to 1,600 sq ft, and the arithmetic matters
Indianapolis caps a secondary dwelling unit at 720 sq ft, the smallest in the table; Albuquerque and Jacksonville at 750; ten cities at 800 or a formula built around 800. San Antonio, Minneapolis and Milwaukee allow up to 1,600. Watch the direction of the formula: Louisville's 800 sq ft or 30% of the house, whichever is greater, and Charlotte's 600 or 70%, whichever is greater, guarantee a floor; Jacksonville's 750 or 25%, whichever is less, and Portland's 800 or 75%, whichever is less, impose a ceiling that shrinks with the house. Three cities measure something other than floor area: Jacksonville and Kansas City cap the footprint, Cincinnati the footprint as a share of the lot.
Two units per lot in ten cities
Phoenix, Tucson, Seattle and Sacramento allow two ADUs outright (Phoenix and Tucson a third if one is affordable on a large lot), Portland allows two in its R20 to R2.5 zones, and the California cities add a junior ADU to the detached unit. Everywhere else the answer is one per lot, and Chicago requires half of any two or more new units to be affordable for 30 years.
What the city charges: from a $130 filing to $36,721
The permit fee is a small part of the bill in some cities and most of it in others. New York's DOB filing for an 800 sq ft cottage is $130, with the design professional's fee separate; Jacksonville, Louisville, Baltimore (if it were legal) and Fort Worth are under $1,000. The California cities are the expensive end: San Diego charges about $6,490 for a 500 sq ft detached unit and $17,236 for 800 sq ft, San Jose's own estimator averages $12,628 for a detached unit, and San Francisco's fees run 6 to 9% of construction cost. Portland's published sample is $36,721 with system development charges and $17,759 with the waiver you get for a 10-year no-short-term-rental covenant. The 750 sq ft cliff in California is real: Sacramento's estimate doubles from $5,272 at 749 sq ft to $10,624 at 750 when park, flood and transportation fees switch on.
Where the city's own documents disagree
Charlotte's ADU declaration form still prints a 50% size rule where the UDO now says 70%. Milwaukee's information sheet prints a flat 1,300 sq ft cap the code exceeds on large lots. Pittsburgh's zoning code refers to an overlay the city says expired. Fort Worth's zoning section is on a code host no client could reach, so its rental rule is unverified. Each city page states the discrepancy rather than resolving it.
Method
The 30 cities are the ones whose BuildPermitGuide pages have been rewritten from primary sources as of October 2026: the city's zoning code and ADU use standards, its ADU guidance page or bulletin, state statute where it controls, and the current fee schedule, each fetched and quoted on the city's ADU page. The status in the table is the city page's own reading of those documents; a bill that has not been enacted is reported as pending, and where a city document is stale or unreachable the row says so instead of guessing. Fees are the city's own worked example at the stated size or cost, before impact fees, utility connection charges and design fees unless the cell says otherwise. Nothing in this table is estimated from another city's rules or from state law alone. Each city page carries the date its sources were last verified and the change log records when a cited document changes.
BuildPermitGuide, “Where Can You Build an ADU? 30 Cities Compared” (2026), https://buildpermitguide.com/research/adu-rules-by-city/Questions, corrections or a city you want added: contact us.
Frequently asked questions
The city pages behind this table
Each page quotes the code section, exempt-work list and fee schedule it relies on and records the date they were last verified.
- Albuquerque, NM
- Baltimore, MD
- Charlotte, NC
- Chicago, IL
- Cincinnati, OH
- Dallas, TX
- Fort Worth, TX
- Houston, TX
- Indianapolis, IN
- Jacksonville, FL
- Kansas City, MO
- Long Beach, CA
- Los Angeles, CA
- Louisville, KY
- Miami, FL
- Milwaukee, WI
- Minneapolis, MN
- New York, NY
- Philadelphia, PA
- Phoenix, AZ
- Pittsburgh, PA
- Portland, OR
- Sacramento, CA
- San Antonio, TX
- San Diego, CA
- San Francisco, CA
- San Jose, CA
- Seattle, WA
- St. Louis, MO
- Tucson, AZ
Related: ADU Permit Guide · ADU permits in all 50 cities · Garage conversion permit guide · Shed size exemptions compared · Permit fee change log · Open data exports