How Much Does an ADU Permit Cost? 30 Cities Compared

Short answer: it depends on the city far more than on the unit. Using each city's own fee schedule and worked example for a new detached accessory dwelling unit of roughly 500 to 900 square feet, the city's fees run from a $130 filing fee in New York and about $530 to $800 in Jacksonville, Louisville, Baltimore, Fort Worth and Houston, through $1,000 to $3,000 in 14 cities, to about $12,600 in San Jose, $17,200 in San Diego, $17,800 in Portland with its development charges waived and $20,500 in San Francisco. The fee basis explains most of it: the Texas cities price by square footage because state law bars valuation-based fees, Indianapolis and San Antonio charge flat rows, and the California, Arizona and Pacific Northwest cities price on a valuation of $170 to $186 per square foot and then add plan review at 50 to 100 percent of the permit. Impact fees sit outside every one of those figures and can exceed them: Miami's city impact fee is $8,099 on a unit whose permits cost $1,800, Portland's four System Development Charges are $18,962 in the city's sample, and Sacramento's estimate roughly doubles at 750 square feet when the state's impact-fee exemption ends. We read each city's fee schedule, ADU bulletin, fee estimator or published sample and recorded the example, the basis and the add-ons.

$130–$20,500the range of city fees for a new detached ADU across the 30 cities' own examples

7cities under $1,000; 14 between $1,000 and $3,000

4cities over $10,000: San Jose, San Diego, Portland and San Francisco

750 sq ftthe line below which California and Maryland bar impact fees on an ADU

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	New detached ADU, city fees	The city's worked example	Conversion or attached unit	How the fee is computed	Impact fees, charges and add-ons	Schedule the city cites, and notes
Albuquerque, NM	$1,000 to $3,000 ⚠	About $1,142 for a 750 sq ft casita: $160 Site Plan Administrative + building permit $635.05 (Table 112-A on a $67,043 valuation x 0.50 + 65% plan review) + about $350 in electrical, plumbing and mechanical permits; about $997 at 500 sq ft.	A garage conversion is the same site plan, building and trade permits; no separate worked example on the page.	Valuation at $89.39 per sq ft: UAC Table 112-A x 0.50 residential modifier + 65% plan review, itemized trades with a $47 administrative charge each, plus the $160 site plan.	Charged: the fee schedule lists the impact fee assessment as varies, collected separately; zoning and hydrology fees are collected with plan review.	UAC Table 112-A; General Planning Fee Schedule; IDO 4-3(F)(6) (2025 update, eff. April 2026) From July 1, 2026 the city uses the February 2021 ICC valuation table, so the per-square-foot figure may rise.
Baltimore, MD	Under $1,000 ⚠	About $595 for a 600 sq ft detached unit: $150 new-building minimum + $95 plumbing and water and sewer lines + $102 electrical + $55 mechanical + $45 occupancy permit, plus the 5% permit tax and the $125 plan-review application fee.	About $493 for a 500 sq ft interior unit: $150 alteration + $40 plumbing + $60 for ten circuits + $55 mechanical + $45 occupancy, with tax and application.	Flat code lines: alteration $0.30 per sq ft ($50 minimum), addition $10 per 1,000 cu ft ($75 minimum), new building $10 per 1,000 cu ft ($150 minimum), itemized trades.	State law bars impact fees or excise taxes on ADUs under 750 sq ft. Utility connection charges are separate.	BFRCBC 109.6; Md. Land Use 4-504 (Ch. 197 of 2025); Council Bill 26-0195 (pending) The city has no ADU fee line and, as of the page's last check, no enacted ADU law; the figures price the work under the current schedule.
Charlotte, NC	$1,000 to $3,000	About $2,136 for a $150,000 detached ADU: County building $1,203.62 + electrical $169.41 + plumbing $145.03 + mechanical $120.65 (each with a $3 technology charge) = $1,660.71, plus the City's $410 stormwater and $65 zoning review.	About $1,425 for a $60,000 garage conversion: County $949.52 plus the $475 City LDIRL.	Valuation per trade on the LUESA Fee Ordinance table ($59.70 + $12.19 per $1,000 over $3,000 … $1,203.52 + $4.59 above $150,000) plus flat City LDIRL fees.	Not stated as impact fees. A City tree preservation review adds $180 to $300 when trees are affected; a third County review cycle is billed at $145 per hour.	LUESA Fee Ordinance rev. 2026-07-01; City FY2026 IRL schedule; UDO ADU standards Every ADU, including a conversion, goes through County residential plan review; City approval must come before the County's.
Chicago, IL	$1,000 to $3,000	$2,450: the plan-based minimum for new residential construction (a coach house). A $600 non-refundable deposit is collected at submission.	$1,800: the minimum for a permit that increases the number of dwelling units (a basement or attic conversion); the formula computes to $396 for 900 sq ft, so the minimum controls.	Plan-based formula (construction factor x scope factor x area) that falls below the minimums for typical units.	Not stated. Add the Title 17 zoning review fee (not published), a $500 administrative adjustment where one applies, and $500 DOH registration per affordable unit when adding two or more ADUs.	Table 14A-12-1204.3(3) and (4); DOH pre-certification and affordability pages DOH pre-certification comes before the DOB permit; coach houses must be built by contractors in an apprenticeship program.
Cincinnati, OH	$3,000 to $10,000	About $4,095 for a $150,000 new detached ADU: building $2,803.50 ($1,065 + $11.59 per $1,000 above $50,000) + $49 processing + about 11% surcharges = about $3,166, plus HVAC about $464, five plumbing fixtures about $254, IBI electrical $146.45 and the $65 certificate of occupancy.	About $2,937 for a $60,000 garage conversion: building about $2,008 plus the same trades and certificate.	Valuation on the FY2027 B&I schedule plus $49 processing and five surcharges (3% technology, 1% training, 1% financial recovery, 5% planning, 1% state); trades itemized; electrical by IBI.	Not stated as impact fees; utilities are assessed by each provider case by case, and free sewer and water availability requests go to MSD and the water works first.	FY2027 B&I fee schedule (eff. 2026-07-01); IBI fee sheet; Zoning 1421 ADU standards A new address must exist before the permit application; the certificate of occupancy issues only after the owner-occupancy covenant is recorded.
Dallas, TX	$1,000 to $3,000	About $1,627 for a 500 sq ft unit ($535 square-footage fee + $577 plan review minimum + $500 for four trade inspections + $15 technology), $2,227 with the $600 Board of Adjustment fee; 700 sq ft about $1,841 / $2,441.	A garage conversion is a garage conversion permit with the energy code trade; no worked example on the page.	Square footage (Texas LGC 214.907 bars value-based fees): Table A-I $1.07 per sq ft up to 700 sq ft, plan review $0.046 per sq ft or $577, $125 inspection per trade.	Not stated as impact fees. Water and wastewater service connections are a separate application with their own charges; a 10% surcharge applies in planned development, SUP and deed-restricted areas.	Chapter 52 Table A-I; fee schedule eff. 2025-07-01; Sec. 51A-4.209(b)(6)(E) Every ADU needs a Board of Adjustment special exception with a no-rental deed restriction ($600 plus $10 per notification sign), and a homeowner may not build it.
Fort Worth, TX	Under $1,000	About $673 building permit for an 800 sq ft detached guest house ($570 for the first 700 sq ft + $0.53 per sq ft + $33.08 application + $16.87 technology). Trade permits extra.	About $262 for a 400 sq ft attached suite ($61.01 for the first 65 sq ft + $0.45 per sq ft + $49.95). A garage conversion may also need a $591 variance if it removes required parking.	Square footage from the R-3 table of Fee Ordinance 26-28781 (eff. 2026-10-01); Texas LGC 214.907 bars value-based fees.	Not stated. No plan review deposit for accessory structures; a separate electric meter needs a Board of Adjustment variance ($591).	Fee Ordinance 26-28781 (R-3 table); Zoning habitable accessory structure rules The unit must take water, electric and gas from the meters serving the main house and may not be taller than it.
Houston, TX	Under $1,000	About $789 building permit for a 900 sq ft detached unit ($604 square-footage fee + 25% plan review + $33.56 admin); $530 for 600 sq ft. Trade permits extra.	A garage conversion is a residential remodel or conversion permit with plan review; no worked example on the page.	Square footage tier (Texas HB 852 bars valuation-based residential fees): $47 base + $5.36 per 8.17 sq ft after the first 57.16.	Charged: the page says impact fees, utility taps and the designer's fee are on top, without amounts. Trades: plumbing $97.56 minimum, electrical $91.06 minimum + $94 meter loop, HVAC $11.41 per ton + $47.	2026 Building Code Enforcement fee schedule; Chapter 42 (secondary dwelling unit, 900 sq ft) Plan review is listed at 15 business days for new residential construction; a legal survey is required at the first structural inspection.
Indianapolis, IN	$1,000 to $3,000	$1,202 for a new detached unit: Improvement Location Permit $140 + structural accessory permit $490 + plumbing $185 + electrical $202 + heating and cooling $185, all flat.	About $865 for a conversion inside the house (no ILP): structural remodel $390 + plumbing $153 + electrical $169 + heating $153.	Flat fees per permit on the DBNS schedule of 2026-01-05; the unit needs five permits.	None on the city schedule: the page says no impact fee appears on the DBNS schedule. A sewer lateral permit from Citizens Energy Group is needed before the structural permit; a septic permit on septic lots.	DBNS fee schedule 2026-01-05; Sec. 743-306 (720 sq ft, owner-occupied lot) Craft permits carry no application fee. A unit over 720 sq ft or a second unit needs a variance ($550 + $29 per standard).
Jacksonville, FL	Under $1,000	About $528 for a 600 sq ft unit with three or fewer inspections: building $302.10 ($112.50 BID minimum + $9.60 + $37.50 + $52.50 debris + $90 plan review) plus electrical $100, plumbing $66, mechanical $60; about $920 for 750 sq ft with eight inspections and a $170 service.	No separate conversion example; attached units are a building permit with no internal access to the house.	Per 100 sq ft of enclosed area ($6.38 BID + $1.60 + $2.13 + $8.75 debris) against minimums ($112.50 BID, $37.50 Development Services, plan review 67% or $90); trades per item.	JEA water and sewer charges and any mobility fee are extra; the city lists a $28 De Minimis Concurrency and Mobility Fee Review. Single-family accessory structures are exempt from the landscape fee.	Ordinance Code Sec. 320.409 (city fees page); Zoning Code 656.403(g) Florida's 1% + 1.5% state surcharges are not shown on the fee page and are left out. Plan review starts after zoning and Development Services sign off; first review 25–30 business days.
Kansas City, MO	$1,000 to $3,000	About $1,146 for a $250,000 detached ADU: building $694.50 ($483 + $1.41 per $1,000 above $100,000) + electrical $157.59 + plumbing $157.59 + mechanical $135.94, each on its own value.	About $639 for an $80,000 basement conversion: building $395.74 + trades $83.98, $83.98 and $75.32.	Valuation table in Sec. 18-20(b)(2), applied separately to the building permit and each trade permit; no plan review fee.	Not stated as impact fees. Water and sewer connection charges (KC Water) and recording the owner-occupancy deed restriction are separate.	KC Code Sec. 18-20(b)(2); Zoning 88-305-15; IB170 A contractor building a detached accessory building over 400 sq ft needs a city Residential Building Contractor license; plan review goal seven business days.
Long Beach, CA	$3,000 to $10,000 ⚠	About $5,229 for an 800 sq ft new detached ADU ($140,736 valuation); about $4,416 for 600 sq ft ($1,950 combination permit + $1,105 plan check + $528 zoning + NPDES $371 + processing, state, records and C&D review fees) plus a refundable C&D deposit of $3,167.	About $2,089 for a 400 sq ft garage conversion valued at $42,000: $1,025 combination permit + $581 plan check + $310 zoning plan check + processing and state fees.	Valuation ($175.92 per sq ft new, $105 conversions): combination permit = 150% of the building fee, plan check 85%, zoning plan check 0.5% ($310 minimum), NPDES $2 per $1,000 + 75%, $115 processing, 5% records fee.	Waived at 750 sq ft or less (state law); above that fire $241.74, police $342.86 and parks $1,781.39 ADU rates apply proportionally; the school district charges $5.38 per sq ft above 500 sq ft.	LBMC 18.06; IB-077; IB-PZ-001; Master Fee and Charges Schedule Council adopted a new fee schedule on 2026-09-08 effective 2026-10-01; the figures are the pre-October rates until the new schedule is posted.
Los Angeles, CA	$1,000 to $3,000	About $2,696 permit plus plan check for a $150,000 ADU ($3,723 at $250,000), surcharges included; the combined permit covers the trades.	Same valuation formula; LADBS's sample one-story detached ADU valued at $121,200 printed $8,800.20 in all, $6,227 of it LAUSD school fees.	Valuation: combined building-mechanical permit plus plan check at 90% of the permit fee, with surcharges.	City impact fees (Residential Development Fee, Dwelling Unit Construction Tax) only at 750 sq ft or more, proportional to the house; LAUSD school fees above 500 sq ft ($6,227 in the sample); no park or linkage fees.	LADBS Permit Fee Calculator; IB P/BC 2026-150; LADBS sample ADU permit The sample permit shows the stack that the calculator does not: $986 permit subtotal, trade lines inside it, $205 plan check, surcharges, school fees and two city construction taxes.
Louisville, KY	Under $1,000	About $573 for a new 800 sq ft detached ADU with six plumbing openings: Planning ADU application $50 + building $84 (800 x $0.105) + electrical $200 + HVAC $105 + state plumbing $134; $1,123 if a conditional use permit ($550) is needed.	About $514 for a $30,000 garage conversion: $50 Planning + building $125 ($50 + $2.50 per $1,000) + electrical $100 + HVAC $105 + plumbing $134.	Per square foot for new floor area ($0.105, 1–2 family) or $50 + $2.50 per $1,000 for alterations ($75 minimum), flat trade permits, state plumbing at $50 + $14 per opening.	Not stated. Sewer and water connection charges are separate.	LMCO 150.096 (rev. 2024-02-06); Planning fee schedule; 815 KAR 20:050; LDC 4.3.27 There is no single ADU fee; you pay each office. The plumbing permit is the state's, not Metro's.
Miami, FL	$1,000 to $3,000 ⚠	About $1,772 in permits for a $150,000 detached 600 sq ft unit: building $750 + $40 application + $330 solid waste + $66 energy + $18.75 state surcharges, three $154 trade permits and a $105 certificate of occupancy; about $2,526 at $250,000.	No conversion example; attached or internal ADUs are capped at 500 sq ft and priced the same way on their cost.	0.50 of estimated construction cost per permit, read as one-half of one percent, $110 minimum, plus a $40 application fee and surcharges on each.	Charged: City Code Chapter 13 impact fees on every new dwelling unit, $8,099 at the single-family detached row ($164 police, $704 fire-rescue, $413 general services, $6,818 parks), with Zoning deciding the row; county road and school impact fees extra at rates no city document states. Renting the unit: $300 registration then $250 a year.	City Code 10-18 (as amended by Ord. 14439); Chapter 13; City Code 2-214 The page title's $10,000+ ceiling is the permits plus the $8,099 city impact fee. A county code-compliance surcharge of unstated rate also applies.
Milwaukee, WI	$1,000 to $3,000	About $2,430 for an 800 sq ft detached ADU: $0.55 per sq ft building permit + $0.25 per sq ft plan review + $65 energy code + erosion control ($250 + $175), with the 1.6% surcharge and processing = $1,188.08; plus the $450 assessor charge, electrical $375.52, plumbing $223.20, HVAC $192.64.	About $1,529 for a 600 sq ft basement ADU costing $45,000: building side $1,153.92 (1.6% of cost + review) + electrical $192.64 + plumbing $106.36 + ductwork $75.80.	Per square foot for new construction ($0.55 permit, $0.25 review), 1.6% of cost for alterations, plus a 1.6% surcharge and $20 to $25 processing per permit.	Not stated as impact fees. The assessor's MCO 81-6 service charge is $450 per new dwelling unit or $250 for an alteration.	MCO 200-33 (DNS 2026 fee schedule); MCO 81-6; MCO 295-505 Detached units need separate site utility plans and three copies of plans; an owner must live in the existing house at application.
Minneapolis, MN	$3,000 to $10,000	About $3,536 for a $150,000 detached ADU: building permit $1,900.50 + 65% plan review $1,235.33 + state surcharge $75 + $325 zoning application. Plumbing, mechanical and state electrical permits extra.	About $2,098 for a $60,000 basement ADU ($1,056.50 permit + $686.73 plan review + $30 surcharge + $325 zoning).	Valuation ($950.50 for the first $50,000 + $10.60 per $1,000; $1,480.50 + $8.40 above $100,000) + 65% plan review + 0.0005 x value state surcharge + a flat $325 zoning fee.	A Metropolitan Council sewer availability charge may apply: one SAC unit is $2,485 in 2026. Plumbing $41.40 per fixture; electrical permits are the state's (DLI).	Building permit fee schedule; Table 525-1 (zoning); Met Council SAC Detached ADUs need frost footings, rated walls within 5 ft of the lot line and a new water service if the existing one is undersized.
New York, NY	Under $1,000	$130: an 800 sq ft detached cottage files as a new building at $0.06 per sq ft with a $130 minimum. PE/RA, plumbing and electrical permits extra.	About $469 for a $120,000 basement or garage conversion (Alteration Type 1: $170 minimum for the first $5,000 plus $2.60 per $1,000).	DOB filing fee by floor area (new building) or job cost (alteration); no ADU-specific line.	Not stated. DOB's page lists no ADU fee; design professional, trade permits and any City Planning or Landmarks review are separate.	Admin Code Table 28-112.2 as amended by Local Law 128 of 2024 (eff. 2025-12-21) Half the fee is due with the application and the balance before the permit, because the work changes the certificate of occupancy.
Philadelphia, PA	Under $1,000	No new detached ADUs are permitted; the page's examples are conversions.	About $533 for a 600 sq ft conversion ($189 zoning use registration, $139.50 building alteration, $57.50 plumbing, $70.50 electrical minimum, $76.50 ductless mechanical) and about $852 for an 800 sq ft unit with $6,000 of electrical and ducted HVAC.	Flat L&I rows: building alteration $76 for the first 500 sq ft + $56 per 100; plumbing $50 for 7 fixtures; electrical $25 per $1,000 ($63 minimum); mechanical $69 or $189; each plus $7.50 in surcharges.	Not stated. No certificate of occupancy fee as part of the building permit.	L&I fee summary PG_012; zoning fee summary PZ_008; ADU checklist ADUs are allowed only inside an existing building in RSA-5/CMX-1 or a historic structure, in some Council Districts, with owner occupancy.
Phoenix, AZ	$1,000 to $3,000	About $2,124 for a 600 sq ft detached ADU valued at $102,480 ($1,180 permit + $944 plan review); $1,573 at 400 sq ft, $3,226 at 1,000. Plus $98 plot plan review; trades not itemized.	A garage or carport conversion is a building permit with replacement parking; no worked example on the page.	Valuation at $170.80 per sq ft (R-3 Type VB): Table A $703 on the first $50,000 + $9 per $1,000, plan review 80% above $50,000.	Charged in growth-area impact fee zones at permit issuance, plus water and sewer fees for meters and service; the page says ask the Growth and Infrastructure team what applies to the address.	2026 Development Fee Schedule Appendix A.2 (eff. 2026-01-20); Building Valuation Table; Zoning 706.A.8 Free standard plans from the ADU Standard Plan Library cannot be modified. Two ADUs are allowed per single-family lot.
Pittsburgh, PA	$1,000 to $3,000 ⚠	About $1,641 for a $150,000 detached unit: PLI building $914.50 ($6 per $1,000 + $14.50 fixed) + zoning review $150 + electrical $141.50 + mechanical $141.50 + ACHD plumbing $293 ($117 plan + 8 fixtures at $22).	About $908 for a $60,000 basement conversion: building $374.50 + zoning $60 + electrical $141.50 + mechanical $141.50 + ACHD $190.	Valuation: PLI residential base fee $6 per $1,000 ($130 minimum) plus fixed fees, zoning review $1 per $1,000 ($50 minimum), county plumbing per plan and fixture.	Not stated. A Zoning Board of Adjustment hearing is $400 if relief is needed.	PLI 2026 Fee Schedule; ACHD fee schedule; Zoning 912.08 (ADU Overlay Districts) ADUs are allowed only inside an ADU Overlay District today; the citywide bill is held in Council. PLI's permitting page puts attached 1–2 family houses in the commercial category ($605 minimum).
Portland, OR	Over $10,000 ⚠	$36,720.91: PP&D's published sample for a new detached ADU at July 2023 rates, of which $18,962 is four System Development Charges; about $17,759 with the SDC waiver, still including an $8,070 water service and a $749 school excise tax.	About $2,864 for a $60,000 basement conversion: $1,868 in building permit, 65% plan review, Development Services fee, 12% state surcharge and zoning inspection, plus about $997 in electrical, plumbing and mechanical permits.	Valuation (ICC Building Valuation Data for new units, 33.3% of it for conversions): $797.28 for the first $50,000 + $6.81 per $1,000, plan review 65%, trades per item.	SDCs (sanitary $6,639, parks $7,101, transportation $2,941, water $2,281 in the sample) are waived with a 10-year covenant that no structure on the property is a short-term rental; revoking it costs 150% of current SDCs. School excise tax $748.80.	PP&D building permit fee table; PP&D detached ADU sample (July 2023); ADU SDC waiver program The sample is the only published total for a new detached ADU and predates the current fee table; the conversion example uses 2026 rates.
Sacramento, CA	$3,000 to $10,000	About $5,272 for a 749 sq ft detached ADU per the city's own estimate CDD-0419 (valuation $170.80 per sq ft: $1,267.56 permit + $532.37 plan review + Fire, Planning, excise, General Plan and technology fees); $10,624 at 750 sq ft and $14,843 at 1,200 once impact fees switch on.	A garage conversion is a Residential Remodel permit valued at $101.16 per sq ft; no worked total on the page.	Valuation at $170.80 per sq ft with plan review, Fire Department administrative, inspection and plan review fees, Planning inspection ($526) and review ($263), and the city's surcharges, all in the CDD-0419 estimate.	Waived at 749 sq ft or less (state law); at 750 sq ft the estimate adds park $2,617.50, flood control $1,575 and transportation $1,154.64. School impact fees and regional sanitation and sewer fees are not included.	CDD-0419 (rev. 2026-07-12); CDD-0245; City Code 17.228.105 The one-square-foot step from 749 to 750 roughly doubles the city's estimate; free shelf-ready plans top out at 747 habitable sq ft.
San Antonio, TX	$1,000 to $3,000	$1,136.30 for an 800 sq ft detached casita (the 501–1,000 sq ft row), $1,227 with the two 4% surcharges: one combination permit covering building, trades, a $230 plan review and the $73.60 sewer fee. Rows run $752.10 (up to 500 sq ft) to $1,603.20 (1,501–1,600).	No separate conversion line; the combination permit is priced by square footage whatever the construction.	Flat combination-permit rows by square footage on the FY 2027 Development Fee Schedule (revised Sept 2026).	SAWS water and wastewater impact fees are set by SAWS and are not in the table. City development and permitting fees and SAWS impact fees may be waived when the house or the ADU is rented at or below 80% of AMI for 5 years.	DSD FY 2027 Development Fee Schedule; UDC 35-371 Plan review is invoiced first and the rest after approval; staff processing adds $11.50 per paper application.
San Diego, CA	Over $10,000	About $17,236 for an 800 sq ft detached ADU: $8,085.26 plan check + $8,401.90 inspection on the new-dwelling line + $737 General Plan fee + $12.16 mapping; a detached unit up to 500 sq ft uses the addition line, about $6,490.	An attached ADU or conversion up to 1,100 sq ft uses the addition/remodel line: about $9,922 for 800 sq ft ($5,607 plan check + $3,566 inspection + the two fees).	Flat lines by unit size on IB 501 Table 501A ($3,512.92 + $2,228.29 for the first 500 sq ft, then $6.98 and $4.46 per sq ft; new-dwelling line above 500 sq ft detached), plus the $737 General Plan Maintenance Fee.	Development Impact Fees exempt for ADUs under 750 sq ft, JADUs, and the first two ADUs on a lot regardless of size (unless SB 9); school fees only when the unit creates 500 sq ft or more; RTCIP fees when there is more than one ADU; IB 501 lists a 2.5-hour impact-fee assessment charge ($442.10).	IB 501 Table 501A; IB 400; SDMC 142.0640(b)(1) The step at 500 sq ft is the largest single break in the table: a detached ADU one square foot over it moves from the addition line to the new-dwelling line.
San Francisco, CA	Over $10,000	About $20,500 for a $300,000 detached cottage: $7,165 at DBI plus $13,348 at Planning, before $1,500 to $2,000 in trade permits; the city's own guide puts City fees at 6 to 9% of construction cost.	About $10,400 for a $125,000 garage conversion: DBI $3,826 ($2,787 plan review + $1,039 issuance) plus Planning $6,602, about 8.3%.	Valuation: DBI Table 1A-A plan review and issuance, plus the Planning Department's own building-permit application fee ($5,638 + 3.855% of cost above $100,000).	Impact fees exempt for units under 750 sq ft or on lots with three or fewer existing units; above that, proportional to the primary home. School facility fees calculated separately by DBI. Trades: plumbing $549 or $809, mechanical $290, electrical $740.	DBI Table 1A-A (eff. 2026-07-12); Planning fee schedule; Planning Code 207.2 Two payments at DBI: a filing fee that starts review and an issuance fee at approval. The Planning fee, not DBI's, is the larger half.
San Jose, CA	Over $10,000 ⚠	About $12,628 for a detached ADU up to 750 sq ft: the city fee estimator's September 2026 average ($3,912 permit issuance, $2,508 plan check, $2,078 trade permits, $4,129 taxes); $21,446 for 751 to 1,200 sq ft.	About $10,298 for an attached ADU up to 750 sq ft (estimator average); $18,697 for 751 to 1,200 sq ft. No separate conversion figure.	City fee estimator averages of recent permits by ADU type and size band; the fixed processing line is $422 up to 750 sq ft and $633 above.	None up to 750 sq ft of livable space (state law); above that, impact fees in proportion to the primary home. Construction taxes are inside the estimator figures.	Building Division Fee Estimator (Sept 2026); Schedule of Fees and Charges eff. 2026-07-01; SJMC 20.80.175 The estimator reports averages, not a schedule, so a given project can land above or below the figure; fees are paid in stages (plan check at intake, permits and taxes at issuance).
Seattle, WA	$3,000 to $10,000	$3,453 for SDCI's own 500 sq ft DADU example (valued at $93,145), $3,632 with the 5% technology fee and $6.50 state surcharge; about $5,248 at 1,000 sq ft. Electrical, plumbing and sewer extra.	About $2,624 for a $60,000 AADU conversion inside the house (index $1,246.50 doubled, plus fees).	Valuation at $186.29 per sq ft (Director's Rule 5-2025): permit fee and plan review fee are each 100% of the Table D-1 index.	King County sewer capacity charge on every new connection, billed quarterly for 15 years (amount set by the county); SDCI electrical permit (60–200 A feeder $146 + circuits + $55.48 admin), Public Health plumbing $137 + $27 per fixture, possible side sewer permit.	2026 Fee Subtitle Table D-1; SDCI 2026 Fee Summary (DADU example, up 18.7% from 2025); Tip 116B About 75% of the fee is due at intake; intake appointments can be 2 to 4 months out for a custom ADU, 2 to 6 weeks for a pre-approved plan.
St. Louis, MO	$1,000 to $3,000 ⚠	About $1,875 for a $150,000 detached unit: building permit $1,525 ($25 + $10 per $1,000 above $3,000) plus roughly $350 in trade permits (electrical new service $145, plumbing about $140 for six fixtures, furnace and condenser $65).	About $1,175 for an $80,000 garage conversion: building $825 plus the same trades.	Valuation: $25 application + $10 per $1,000 or fraction above $3,000 on the estimated cost including trades; trade permits itemized.	Not stated as impact fees. Water taps and sewer connections are $25 each on the plumbing permit if the unit gets its own; a $120 Certificate of Inspection is required before occupancy.	Building Division fee table; electrical, plumbing and mechanical fee pages; Zoning 26.20.021 (Ord. 72036) The ordinance's codified table still prints an older rate; the page uses the Division's live figures. Owner-drawn plans need no seal on an owner-occupied 1–2 family home.
Tucson, AZ	$1,000 to $3,000	About $1,740 for a 600 sq ft casita from the Model Plan Library (permit $1,544.80 + $176.55 site plan review + $18.54 filing; construction document review waived); a custom 400 sq ft casita about $1,850, 1,000 sq ft about $3,190.	An attached casita or garage conversion is an ADU permit under the same standards; no worked example on the page.	Valuation at $170.80 per sq ft: $1,038.05 for the first $50,000 + $9.64 per $1,000 to $100,000, then $1,520.05 + $8.25; plan review 50%; digital filing fee 1% ($18.54 minimum).	Charged: development impact fees for parks, streets and police on every casita; the city is updating its impact fee program, so the page says use the city's calculator for a current figure.	PDSD FY27 fee schedule (eff. 2026-07-01); Construction Valuation Table; UDC casita standards (2024-11-21) Model-plan permits go through the 15-day Fast Lane instead of the roughly 30-day new-building review; designers charge their own license fee for the plan.

The status bands the city's own worked example for a new detached ADU as the city page states it on the date it was last verified, counting only city fees (permit, plan review, zoning and the trade permits where the city's example includes them); each example says whether trade permits are inside or extra. Examples differ in size and construction value because they are the cities' own, so compare them as the city's answer to a typical unit, not as a priced-alike quote. The conversion column gives the city's example for an attached unit or a conversion where it publishes one. Impact fees, development charges, utility connection charges, school fees and deposits are listed separately and are never inside the band. A flag marks a figure that is an average, a dated sample, a superseded rate or a city whose documents disagree. Download the table as CSV.

What the comparison shows

A 150-to-1 spread, and the fee basis explains most of it

Baltimore, Fort Worth, Houston, Jacksonville, Louisville, New York, Philadelphia charge under $1,000 for the city's own detached-ADU example; Albuquerque, Charlotte, Chicago, Dallas, Indianapolis, Kansas City, Los Angeles, Miami, Milwaukee, Phoenix, Pittsburgh, San Antonio, St. Louis, Tucson between $1,000 and $3,000; Cincinnati, Long Beach, Minneapolis, Sacramento, Seattle between $3,000 and $10,000; and Portland, San Diego, San Francisco, San Jose above $10,000. The cheap cities share a basis: New York files an 800 sq ft cottage at $0.06 per square foot with a $130 minimum; Houston, Dallas, Fort Worth, Louisville and Milwaukee price by the square foot (Texas Local Government Code 214.907 and HB 852 bar valuation-based residential fees); Jacksonville charges per 100 square feet against minimums; Baltimore and Indianapolis use flat code lines. The expensive cities price on valuation and then multiply: Los Angeles adds plan check at 90 percent of the permit, Phoenix 80 percent, Seattle 100 percent, Portland, Minneapolis and Albuquerque 65 percent, Tucson 50 percent, Long Beach 85 percent on a combination permit that is itself 150 percent of the building fee. San Diego's flat lines are the outlier: $8,085 plan check plus $8,402 inspection for any detached ADU over 500 square feet, before its $737 General Plan fee. San Francisco's bill is two bills, and the Planning Department's ($13,348 on a $300,000 cottage) is the larger.

Three cities use the same $170.80 per square foot, and land in three different bands

Phoenix, Sacramento and Tucson all value a wood-frame dwelling at $170.80 per square foot, the ICC figure, and Seattle uses $186.29, Long Beach $175.92 and Albuquerque $89.39. What they do next sets the bill. Phoenix charges $703 on the first $50,000 plus $9 per $1,000 and 80 percent plan review: about $2,124 for 600 square feet. Tucson charges $1,038 plus $9.64 per $1,000 and 50 percent review, and waives construction document review for a model plan: about $1,740 for a 600 sq ft model-plan casita. Sacramento's estimate for a 749 sq ft unit is about $5,272 because Fire Department, Planning, excise, General Plan and technology fees ride on the same valuation. Albuquerque's lower valuation, a 0.50 residential modifier and 65 percent review put a 750 sq ft casita at about $1,142 with trades. Seattle doubles its Table D-1 index for permit plus plan review: $3,453 on SDCI's own 500 sq ft example, up 18.7 percent from 2025.

Impact fees are the other half of the bill, and the 750-square-foot line decides them in seven cities

California bars impact fees on an ADU of 750 square feet of livable space or less, which the pages for Los Angeles, San Diego, San Jose, San Francisco, Sacramento and Long Beach each restate, and Maryland's 2025 ADU law does the same for Baltimore. Above the line the fees arrive at once: Sacramento's estimate goes from $5,272 at 749 square feet to $10,624 at 750 (park $2,617.50, flood control $1,575, transportation $1,154.64), Long Beach's fire, police and parks rates apply proportionally, and Los Angeles charges its Residential Development Fee and Dwelling Unit Construction Tax from 750 square feet. San Diego exempts the first two ADUs on a lot regardless of size. School fees have their own line at 500 square feet: $6,227 in LADBS's sample permit, $5.38 per square foot in Long Beach, exempt below 500 in San Diego. Where no exemption exists the impact fee can dwarf the permit: Miami's Chapter 13 fees are $8,099 at the single-family detached row on a unit whose permits total about $1,772, with county road and school fees on top; Phoenix collects impact fees in its growth-area zones; Tucson charges parks, streets and police fees on every casita; Albuquerque's schedule says the assessment varies; Houston says impact fees and utility taps are on top. Portland is the one city that publishes the whole stack: $36,721 for a new detached ADU in its sample, $18,962 of it four System Development Charges that are waived for a 10-year covenant against short-term rental. Seattle's King County sewer capacity charge is billed quarterly for 15 years, and Minneapolis's Metropolitan Council sewer availability charge is $2,485 per unit when it applies.

The add-ons that are neither permit nor impact fee

Nearly every city attaches something to an ADU that no other project pays. Chicago collects a $600 non-refundable deposit at submission and $500 per affordable unit when two or more ADUs are added. Miami charges a $105 certificate of occupancy and, to rent the unit, $300 registration then $250 a year. Dallas requires a $600 Board of Adjustment special exception for every ADU. Louisville's Planning application is $50, or $550 for a conditional use permit when the unit exceeds 800 square feet and 30 percent of the house. Minneapolis charges a $325 zoning application, Albuquerque a $160 site plan, Indianapolis a $140 Improvement Location Permit, Philadelphia a $189 use registration, Charlotte $475 of City stormwater and zoning review plus $180 to $300 for tree review. Milwaukee's assessor charges $450 per new dwelling unit. St. Louis requires a $120 Certificate of Inspection before anyone moves in, Cincinnati a $65 certificate of occupancy after the owner-occupancy covenant is recorded. Long Beach holds a refundable construction-and-demolition deposit of 3 percent of value, $3,167 on a 600 sq ft unit. Pittsburgh's zoning board hearing, if relief is needed, is $400.

Conversions cost less everywhere a city prices them, except where a minimum controls

Twenty cities publish a conversion or attached-unit figure, and it is lower than the new-detached figure in every one: about $469 for a $120,000 conversion in New York, $493 for a 500 sq ft interior unit in Baltimore, $514 in Louisville, $639 for an $80,000 basement in Kansas City, $865 in Indianapolis (no Improvement Location Permit), $908 in Pittsburgh, $1,175 in St. Louis, $1,425 in Charlotte, $1,529 in Milwaukee, $2,089 for a 400 sq ft garage in Long Beach, $2,098 in Minneapolis, $2,624 in Seattle, $2,864 in Portland, $2,937 in Cincinnati, $9,922 for an 800 sq ft attached unit in San Diego, $10,298 in San Jose and $10,400 for a $125,000 garage in San Francisco. Chicago is the exception that proves the rule: its formula computes to $396 for a 900 sq ft basement unit, but the $1,800 minimum for adding a dwelling unit controls, against $2,450 for a coach house. Philadelphia publishes only conversions, because new detached ADUs are not permitted there. Los Angeles prices conversions on the same valuation formula, and its sample permit is the one place a reader can see the whole bill: $8,800 on a $121,200 unit, of which the permit and plan check were under $1,500 and the school fees $6,227.

Where the figure is an average, a dated sample or a superseded rate

San Jose's figures are its fee estimator's averages of recent permits ($12,628 for a detached unit up to 750 square feet), not a schedule line, so a given project can land above or below them. Portland's only published total for a new detached ADU is a sample at July 2023 rates. Long Beach's Council adopted a new fee schedule effective October 1, 2026 that was not yet posted when the page was verified. Albuquerque switched its valuation basis to the February 2021 ICC table on July 1, 2026, so its $89.39 per square foot may be superseded. Miami's code prints the residential rate as 0.50 without a percent sign. St. Louis's codified table prints $6 per $1,000 while the Building Division charges $10. Pittsburgh allows ADUs only inside an overlay district today, and its permitting page puts attached houses in a commercial category with a $605 minimum. Baltimore's ADU ordinance was still in committee past the state deadline, so its figures price a unit the zoning may not yet allow. The table flags those rows rather than resolving them.

Method

The 30 cities are the ones whose BuildPermitGuide pages have been rewritten from primary sources as of October 2026. For each city the ADU page quotes the fee schedule or ordinance, the building valuation table where one is used, the city's ADU bulletin, fee estimator or published sample permit, and the impact fee or development charge schedule, and works an example for a new detached unit and, where the city publishes one, a conversion. The figures in the table are those worked examples, counting city fees only: permit, plan review, zoning review and the trade permits where the city's example includes them. Each example states its unit size or construction value and whether trades are inside or extra, because the cities' own examples differ. Impact fees, development charges, utility connection charges, school fees and deposits are recorded in their own column and never inside the band. Nothing is estimated from another city's schedule, and where a figure is an average, a dated sample or a superseded rate, or the city's documents disagree, the row carries a flag instead of a resolution. Each city page carries the date its sources were last verified, and the change log records when a cited schedule changes.

Use this data. The table and CSV are published under CC BY 4.0. Cite it as:

BuildPermitGuide, “How Much Does an ADU Permit Cost? 30 Cities Compared” (2026), https://buildpermitguide.com/research/adu-permit-fees/

Questions, corrections or a city you want added: contact us.

Frequently asked questions

Between $130 and about $20,500 in city fees for a new detached unit across the 30 largest cities we compared, using each city's own example: under $1,000 in New York, Jacksonville, Louisville, Baltimore, Fort Worth, Houston and Philadelphia (conversions only); $1,000 to $3,000 in 14 cities including Phoenix, Chicago, Los Angeles, Dallas, Charlotte and Milwaukee; $3,000 to $10,000 in Seattle, Minneapolis, Cincinnati, Sacramento and Long Beach; and over $10,000 in San Jose, San Diego, Portland and San Francisco.

Because the basis differs. Texas cities price by square footage since state law bars valuation-based fees; Indianapolis and San Antonio charge flat rows; New York charges a filing fee with a $130 minimum. California, Arizona and Pacific Northwest cities price on a valuation of $170 to $186 per square foot and add plan review at 50 to 100 percent of the permit, and San Francisco adds a Planning Department fee larger than the building department's.

In California, on an ADU of 750 square feet of livable space or less: Los Angeles, San Diego, San Jose, San Francisco, Sacramento and Long Beach each restate the rule, and Maryland's 2025 law does the same for Baltimore. Above the line Sacramento's estimate roughly doubles and Los Angeles and Long Beach charge proportionally. Portland waives its development charges for a 10-year no-short-term-rental covenant. Miami ($8,099), Phoenix, Tucson, Albuquerque and Houston charge impact fees on an ADU.

Less than a new detached unit in every city that publishes a figure: about $469 for a $120,000 conversion in New York, $514 in Louisville, $639 in Kansas City, $865 in Indianapolis, $908 in Pittsburgh, $1,175 in St. Louis, $1,425 in Charlotte, $1,800 in Chicago (a minimum), $2,089 in Long Beach, $2,098 in Minneapolis, $2,624 in Seattle, $2,864 in Portland, $2,937 in Cincinnati and about $10,400 in San Francisco.

Sometimes. San Antonio, San Diego, Long Beach and Los Angeles issue one combination permit that covers the trades; the examples for Miami, Milwaukee, Louisville, St. Louis, Indianapolis, Kansas City, Charlotte, Pittsburgh, Cincinnati, Albuquerque, Baltimore and Jacksonville add the trade permits in. New York, Houston, Phoenix, Seattle, Minneapolis, Fort Worth, Tucson and San Francisco price the building permit and say the trades are extra; each row in the table says which.

A zoning or planning filing in many cities ($50 in Louisville, $160 in Albuquerque, $189 in Philadelphia, $325 in Minneapolis, $475 in Charlotte, $600 Board of Adjustment in Dallas), a certificate of occupancy or inspection (Miami $105, Cincinnati $65, St. Louis $120), deposits (Chicago $600, Long Beach $3,167 refundable), Milwaukee's $450 assessor charge, utility connection or sewer capacity charges (Seattle, Minneapolis $2,485, Jacksonville, Dallas, Kansas City) and school fees above 500 square feet in the California cities.

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.