🏠 Accessory Dwelling Unit (ADU) permit in Missouri
A secondary, self-contained living unit on a single-family lot — detached, attached, or conversion of existing space (garage/basement). Here is the Missouri-specific rule: who issues it, typical fees, timeline, go / no-go, and the official source to verify.
Accessory Dwelling Unit (ADU) permit in Missouri
The Missouri rule for a accessory dwelling unit (adu), with fee range, timeline, go / no-go, and the official source.
Missouri
🏠 Accessory Dwelling Unit (ADU)
Exact permit fees are set by the local building department. WikEst shows the published or code-based range where one exists, linked to its official source — verify the final amount at the source before budgeting.
🏠 Accessory Dwelling Unit (ADU) permit fee in Missouri
Permit requiredCase by casecity authority
Permit fee range
Permit fees set locally by each municipality — verify with the city building department (St. Louis Building Division or KC Permits Division).
Typical timeline
Varies by municipality — simple permits often same-day to ~2 weeks; full plan-review permits several weeks.
Setback
—
Exempt if
Not size-exempt
ADUs require a building permit plus zoning/use approval. Missouri has no statewide residential building code, so allowance and rules are set locally (e.g., St. Louis and Kansas City each have their own requirements). Verify with your municipal building department.
Official sources: American Wood Council — Missouri Adopted I-Codes (local adoption; no statewide mandate) · City of St. Louis — Building Division
Representative cities for Missouri: St. Louis, Kansas City.
All 20 project fee ranges in Missouri
Official-source ranges where published; “By local jurisdiction” means no flat fee is published and the amount is set case by case.
| Project | Permit? | Authority | Fee range | Go / no-go |
|---|---|---|---|---|
| 🏠 Accessory Dwelling Unit (ADU) | yes | city | Permit fees set locally by each municipality — verify with the city building department (St. Louis Building Division or KC Permits Division). | case-by-case |
| 🪵 Deck / Porch | conditional | city | Permit fees set locally by each municipality — verify with the city building department. | allowed |
| 🧱 Fence / Wall | conditional | city | Usually no building permit under the height threshold; zoning setback/height rules apply. Verify locally. | allowed |
| 🛖 Shed / Outbuilding | conditional | city | No fee under the exemption; a permit fee applies if over the local threshold. | allowed |
| 🪜 Basement Finish | yes | city | Building permit fee set locally; trade permits billed separately. | allowed |
| 🚗 Garage / Carport | yes | city | Building permit fee set locally; zoning clearance may be required first. | allowed |
| ☀️ Rooftop Solar PV | yes | city | Electrical/structural permit fee set locally by the municipality. | allowed |
| 🌡️ HVAC Replacement | yes | city | Mechanical permit fee set locally by the municipality. | allowed |
| 🍳 Kitchen Remodel | yes | city | Building permit fee; trade permits (plumbing/electrical) billed separately. | allowed |
| 🛁 Bathroom Remodel | yes | city | Building permit fee; trade permits (plumbing/electrical) billed separately. | allowed |
| 🏗️ Room Addition | yes | city | Building permit fee based on valuation; zoning and plan review apply. | allowed |
| 🪟 Window / Door Replacement | conditional | city | Permit fee if changing the opening; in-kind swap is often exempt. | allowed |
| 🏘️ Roof Replacement | conditional | city | Roof-covering permit fee set locally; in-kind re-roof may be exempt. | allowed |
| 🅿️ Driveway / Parking Pad | conditional | city | No building permit for private flatwork; a right-of-way/curb cut needs a separate permit. | allowed |
| 🏊 Swimming Pool / Spa | yes | city | Building permit fee; barrier fencing required by code. | allowed |
| 🧱 Retaining Wall | conditional | city | No fee under the exemption; a permit applies if over the threshold. | allowed |
| 💥 Demolition / Teardown | yes | city | Demolition permit fee set locally by the municipality; verify with the city building department. | allowed |
| 🚰 Septic System | yes | state | Onsite sewage construction permit fee set by the MO DHSS Onsite Sewage Program; verify with the program (573-751-6095). | allowed |
| 🔌 EV Charger | yes | city | Electrical permit fee set locally by the municipality. | allowed |
| ⚡ Standby Generator | yes | city | Electrical (and gas, if fuel-fired) permit fee set locally by the municipality. | allowed |
Missouri rule at a glance
Needs permit
yes
Issuing authority
city
Typical fee
Permit fees set locally by each municipality — verify with the city building department (St. Louis Building Division or KC Permits Division).
Typical timeline
Varies by municipality — simple permits often same-day to ~2 weeks; full plan-review permits several weeks.
Setback
—
Exempt if
Not size-exempt
ADUs require a building permit plus zoning/use approval. Missouri has no statewide residential building code, so allowance and rules are set locally (e.g., St. Louis and Kansas City each have their own requirements). Verify with your municipal building department.
Official sources for this rule: American Wood Council — Missouri Adopted I-Codes (local adoption; no statewide mandate) · City of St. Louis — Building Division
Frequently asked questions
Does a accessory dwelling unit (adu) need a permit in Missouri?
In Missouri, a accessory dwelling unit (adu) is generally required to have a permit. Issuance is at the city level. Confirm the exact threshold with the local building department using the sources on this page.
Who issues the accessory dwelling unit (adu) permit in Missouri?
Missouri permits for this project are handled at the city level — usually the city or county building department. Use the county permit authority lookup to find the exact office for your property.
How much does a accessory dwelling unit (adu) permit cost in Missouri?
Fees are set locally in Missouri and are not a single statewide number. Open the official authority link on this page for the current schedule.
What exemptions apply to a accessory dwelling unit (adu) in Missouri?
Baseline exemptions (e.g. small detached structures, low decks) may apply but Missouri or your city can amend them. Verify with the local building department.
🗺️ All projects in Missouri
The full Missouri permit guide across 20 home projects.
📊 Accessory Dwelling Unit (ADU) in every state
Compare the accessory dwelling unit (adu) rule across all U.S. states.
Accessory Dwelling Unit (ADU) in other states
| State | Permit? | Authority | Typical fee | Timeline | Go / No-Go | Key notes |
|---|---|---|---|---|---|---|
| California | Permit required | city | Permit and plan-check fees set by the local jurisdiction; state law limits impact fees on ADUs. Verify with the city building department. | ~3–6 months for full plan review; many cities offer pre-approved plans or over-the-counter review. | Generally allowed | State law (Gov. Code §65852.2) requires cities to approve ADUs ministerially by right in most zones; local design review is limited to objective standards. Local fees, setbacks, and coastal/historic overlays still apply. Exempt: By-right up to 1,200 sq ft (≤800 sq ft for a 1-bedroom unit) under state law. |
| Texas | Permit required | city | Permit and plan-review fees set by the city. Verify with the local building department. | Varies by city; 2–8 weeks. | Restricted | Texas has no statewide ADU mandate; ADUs are allowed only where the local ordinance permits (e.g., Austin, Houston, Dallas). Zoning, size caps, and parking rules apply. Exempt: Allowed only where the local ordinance permits. |
| Florida | Permit required | city | Permit and plan-review fees set by the city. Verify with the local building department. | Varies by city; 2–8 weeks. | Restricted | Florida has no statewide by-right ADU mandate; ADUs are allowed only where the local ordinance permits, with size/setback set by that ordinance. Exempt: Allowed where local zoning permits (e.g., Miami 21, Orlando, Tampa). |
| New York | Permit required | city | Permit and plan-review fees set by the city. Verify with the local building department. | Varies by city; NYC ADU filings may take several weeks. | Restricted | New York has no statewide by-right ADU mandate; ADUs are allowed where local law permits (e.g., the NYC ADU program, Buffalo). Zoning applies. Exempt: Allowed only where the local law permits. |
| Pennsylvania | Permit required | city | Permit fees set by each municipality; Philadelphia adds a $3 city and $4.50 state surcharge per permit plus plan-review fees. No single statewide fee. | Typically ~15 business days for residential alterations (Philadelphia L&I); other PA municipalities vary. | Case by case | ADUs require a building permit plus zoning/use approval. The PA UCC governs construction; local zoning controls whether an ADU is allowed on your lot. Verify with your municipality (e.g., Philadelphia L&I). |
| Illinois | Permit required | city | No flat statewide fee; Chicago calculates fees from construction type, occupancy, square footage, and scope via its online calculator. Other municipalities set their own fees. | — | Case by case | Illinois has no statewide building code; most municipalities use the IRC while Chicago enforces the 2019 Chicago Building Code. ADUs require a building permit plus local zoning approval — Chicago and other cities regulate ADUs through zoning. Verify with your municipality. |
| Ohio | Permit required | city | Columbus minimum permit fee $125; total scales with project valuation and trade permits. Municipal fees vary. | Residential permits ~10 business days (Columbus BZS). | Case by case | Ohio’s Residential Code (based on the 2018 IRC) governs construction; ADUs need a building permit plus local zoning approval. Confirm ADU legality with your city (e.g., Columbus BZS). |
| Georgia | Permit required | city | Atlanta minimum permit cost $150 plus $25 technology fee; total scales with cost of construction. Municipal fees vary. | — | Case by case | Georgia’s mandatory 2024 IRC with Georgia Amendments (eff. Jan 1, 2026) governs construction; ADUs need a building permit plus local zoning approval. Verify with your city (e.g., Atlanta Office of Buildings). |
| North Carolina | Permit required | city | Permit fee based on project valuation; Raleigh uses a published Development Fee Guide / calculator. No single statewide flat fee — verify with the issuing city. | Typically 4–10 weeks (plan review + inspections); Charlotte ADU reviews commonly 50–75 days. | Generally allowed | ADUs are allowed in both Charlotte and Raleigh single-family zones. Owner-occupancy not required in Charlotte. Always confirm zoning, setbacks, and parking with the city planning department. Exempt: Charlotte caps detached ADU at 1,000 heated sq ft or 50% of principal dwelling, whichever is less. |
| Michigan | Permit required | city | Building permit based on project valuation; verify with the city. Detroit issues residential permits in about 5 days. | Typically 5–15 business days; Detroit ~5 days, Grand Rapids 5–10 days for simple projects. | Generally allowed | ADUs are allowed in Michigan subject to local zoning. A building permit and zoning approval are required; some cities cap size and occupant/rental rules. Confirm with Detroit or Grand Rapids planning. Exempt: No state size exemption for an ADU (it is habitable space). |
| New Jersey | Permit required | city | Construction permit based on valuation plus a zoning/land-use fee; verify with the city. | Plan review commonly up to 20 business days for subcode review; zoning first. | Generally allowed | New Jersey permits ADUs subject to local zoning. A UCC construction permit plus zoning approval are required. Jersey City publishes ADU zoning guidance — confirm size, parking, and occupancy rules locally. Exempt: No state size exemption — ADUs are habitable accessory structures. |
| Virginia | Permit required | city | Building permit based on valuation plus a 2% state levy (Virginia Beach); verify with the city. | Residential plan review ~10 business days for new construction; zoning first. | Generally allowed | Virginia law requires localities to allow ADUs in single-family zoning. A USBC building permit and zoning approval are required. Henrico lists ADUs as permit-required. Exempt: No state size exemption — ADUs are habitable accessory structures. |
| Washington | Permit required | city | Valuation-based; Seattle SDCI issue fees scale with project value (no flat state fee). | Seattle pre-approved DADU plans ~2–6 weeks; custom plans longer. | Generally allowed | Washington HB 1337 (2025) mandates ADUs; Seattle also allows two ADUs per lot. Owner-occupancy and extra parking are not required in Seattle. Exempt: Statewide HB 1337 (eff. 2025) allows ≥1 ADU per lot; Seattle allows up to 2 ADUs. |
| Arizona | Permit required | city | Valuation-based; set by the issuing city. | Phoenix ~30–90 days; Tucson ministerial review since the Nov 2024 UDC amendment. | Generally allowed | Arizona has no statewide ADU law. Phoenix and Tucson both allow ADUs by local ordinance; Tucson review is ministerial under state HB 2720. Exempt: Phoenix max 1,000 sq ft; Tucson allows ≥1 ADU per lot (up to 2 on lots with an existing home). |
| Massachusetts | Permit required | city | Valuation-based; set by the issuing city (Boston uses a long-form permit). | Boston: up to ~5 weeks for long-form permit review; longer with zoning relief. | Generally allowed | Massachusetts requires ADUs by right under MGL c. 40A §3A; Boston requires a long-form building permit and zoning review. Exempt: State law (MGL c. 40A §3A) allows ADUs by right on lots with a single-family home. |
| Tennessee | Permit required | city | Valuation-based; Nashville residential fee is $5.00 per $1,000 of valuation. | Nashville DADU review under Metro Code §17.16.250; varies by city. | Generally allowed | Nashville streamlined DADU rules in 2025 (removed alley-access requirement, raised size limits); owner-occupancy is required. Other cities follow state ADU allowances. Exempt: Nashville allows detached ADUs (DADUs) by right in most residential zones (Urban Services District). |
| Indiana | Permit required | city | Building permit fee set by the local building department; zoning/use approval also required. | — | Case by case | ADUs are allowed only where local zoning permits an accessory dwelling unit. A building permit is required for construction. Verify with your city (e.g., Indianapolis BNS or Fort Wayne Community Development). |
| Maryland | Permit required | city | Building permit fee set by the city; zoning/use approval also required. | — | Case by case | ADUs require a building permit and local zoning approval. Maryland’s MBPS governs construction; local zoning controls whether an ADU is allowed. Verify with Baltimore DHCD or Annapolis Planning & Zoning. |
| Wisconsin | Permit required | city | Permit fees set by each municipality — verify with the local building inspection department (Milwaukee DNS or Madison Building Inspection). | Varies by municipality — simple permits often same-day to ~2 weeks; full plan-review permits several weeks. | Case by case | ADUs require a building permit plus zoning/use approval. Wisconsin’s UDC (SPS 320-325) governs one- and two-family dwellings; local zoning controls whether an ADU is allowed on your lot. Verify with your municipal building inspection department. |
| Alaska | Permit required | city | Valuation-based; set by the municipality or borough. | — | Case by case | Alaska has no statewide ADU law. ADUs are allowed only where the local zoning ordinance permits them (rules vary by municipality — Anchorage, Fairbanks, and the boroughs each set their own). When an ADU is permitted by zoning, a full building permit is required. |
| Alabama | Permit required | city | Valuation-based; set by the issuing city or county. | — | Case by case | Alabama has no statewide ADU (accessory dwelling unit) law. ADUs are allowed only where the local zoning ordinance permits them — for example, Birmingham has rezoned to allow ADUs in certain residential zones. When an ADU is permitted by zoning, a full building permit is required. |
| Arkansas | Permit required | city | Valuation-based; Little Rock minimum building-permit fee $50 (work over $5,000 or requiring inspection). | — | Case by case | Arkansas has no statewide ADU law. ADUs are allowed only where the local zoning ordinance permits them (e.g., Fayetteville allows ADUs). When permitted by zoning, a full building permit is required. |
| Colorado | Permit required | city | Valuation-based; set by the issuing city/county. | — | Case by case | Colorado is a home-rule state with no mandatory statewide residential code, so ADU rules vary by jurisdiction. Denver allows ADUs by right through its e-permits process; other cities/counties differ. When permitted by zoning, a full building permit is required. |
| Connecticut | Permit required | city | Valuation-based; set by the city/town. | — | Case by case | Connecticut has a uniform statewide building code, but ADU allowance is set by local zoning, which varies by town. When an ADU is permitted by zoning, a full building permit is required under the 2022 CT State Building Code. |
| Delaware | Permit required | county | Valuation-based; set by the county (unincorporated) or city. | — | Case by case | Delaware has no statewide building/residential code — codes are adopted at the county and municipal level. ADUs are allowed only where the local zoning ordinance permits them (Wilmington and the counties vary). When permitted by zoning, a full building permit is required. |
| Hawaii | Permit required | county | Valuation-based; set by the county building department (R-3 / U occupancy schedule). | Plan review typically several weeks; varies by county workload. | Generally allowed | Hawaii’s statewide ADU law (Act 50, 2008) allows one accessory dwelling unit per single-family lot; the four counties administer permits and set local size/setback rules. Owner-occupancy and parking standards vary by county. Exempt: Statewide ADU law allows one ADU per single-family lot; counties set size limits (commonly 400–1,000 sq ft by county). |
| Iowa | Conditional | city | Valuation-based; set by the issuing city. | — | Generally allowed | Iowa has no statewide ADU mandate; local zoning governs whether ADUs are allowed. Des Moines and Cedar Rapids regulate ADUs by ordinance. Confirm with the local planning and building department before designing. Exempt: Local limits vary by city. |
| Idaho | Permit required | city | Valuation-based; set by the issuing city or, in unincorporated areas, by Idaho DOPL. | Plan review typically 1–3 weeks in Treasure Valley cities. | Generally allowed | Idaho has no single statewide ADU mandate; cities adopt ADU rules by local ordinance. Boise and other growing cities allow ADUs subject to zoning. Verify with the local building department. Exempt: No statewide size exemption; local zoning sets ADU size and lot limits. |
| Kansas | Conditional | city | Valuation-based; set by the issuing city. | — | Case by case | Kansas has no statewide residential code; whether ADUs are allowed is purely local. Some Kansas cities permit ADUs by ordinance, others do not. Confirm with the city planning department. Exempt: Local limits vary. |
| Kentucky | Conditional | city | Valuation-based; set by the issuing city. | — | Generally allowed | Kentucky has no statewide ADU mandate; local zoning governs. Lexington publishes an ADU permit guide, so ADUs are allowed there by ordinance. Confirm with the local planning department. Exempt: Local limits vary. |
| Louisiana | Conditional | city | Valuation-based; set by the issuing parish/city. | — | Case by case | Louisiana has no statewide ADU mandate; local zoning governs. In New Orleans, properties in historic districts (VCC/HDLC) need extra approvals. Confirm with the local planning department. Exempt: Local limits vary. |
| Maine | Permit required | city | Valuation-based; set by the issuing municipality (no statewide flat fee). | Plan review typically 2–4 weeks in staffed cities; over-the-counter where pre-approved. | Generally allowed | Maine has no statewide ADU law. ADUs are allowed only where the local ordinance permits them (e.g., Portland). Verify with your Code Enforcement Officer — many small towns have no ADU provision at all. Exempt: No statewide ADU mandate; size limits set by local ordinance. |
| Minnesota | Permit required | city | Permit fees set by the municipality; verify with the local building department (Minneapolis Development Review or Saint Paul DSI). | Varies by municipality — ADUs with full plan review typically several weeks. | Case by case | An accessory dwelling unit is a dwelling-unit addition and requires a building permit plus zoning/occupancy approval. Whether an ADU is allowed on your lot is set by local zoning; verify with your municipal building department. |
| Mississippi | Conditional | city | Where a jurisdiction enforces a code, fees follow that city/county schedule; many rural counties have no permit fee because no code is enforced. Verify locally. | Varies — only applies where your city/county has adopted a building code. | Case by case | Mississippi has no mandatory statewide building code. Whether an ADU needs a permit depends entirely on whether your city or county has adopted and enforces a residential code, plus local zoning. Confirm with your local building department. |
| Montana | Conditional | city | Where a certified city/county enforces, fees follow that jurisdiction; in non-certified areas a single-family home is exempt from the state building permit (trade permits still apply). Verify locally. | Where enforced, plan review typically 1-4 weeks depending on scope. | Case by case | ADU allowances are set by local zoning. In certified cities (Billings, Missoula) a permit is required; in non-certified areas, residential buildings with fewer than five dwelling units are exempt from the state building permit under MCA 50-60-102, though state electrical/plumbing/mechanical permits are still required. |
| North Dakota | Permit required | city | — | — | Generally allowed | North Dakota has no statewide by-right ADU law; allowance is set by local zoning. Verify with your city/county building department whether ADUs are permitted in your zone. Exempt: No statewide ADU mandate; an ADU is a dwelling and requires a building permit where codes are enforced. |
| Nebraska | Permit required | city | Permit fees set by the municipality; verify with Omaha or Lincoln Building & Safety. | Varies by municipality — ADUs with full plan review typically several weeks. | Case by case | An ADU is a dwelling-unit addition and requires a building permit plus zoning/occupancy approval. Whether an ADU is allowed is set by local zoning. Verify with your municipal building department. |
| New Hampshire | Permit required | city | — | — | Generally allowed | New Hampshire has no statewide by-right ADU law; whether an ADU is allowed depends on local zoning. The structure itself requires a building permit under the state residential code regardless of town ordinance. Exempt: No statewide ADU mandate; an ADU is a dwelling unit and requires a building permit. |
| New Mexico | Permit required | city | — | — | Generally allowed | New Mexico has no statewide by-right ADU law; allowance is set by local zoning. Example: Albuquerque’s Integrated Development Ordinance (IDO) permits one casita (max 750 sq ft) in R-A and R-1 zones as of 2023. Verify with your local planning department. Exempt: No statewide ADU mandate; an ADU is a dwelling and requires a building permit. |
| Nevada | Permit required | city | Valuation-based building + plan-check fees; no flat ADU fee published. Clark County fees scale with valuation. | Clark County (unincorporated) typically administrative approval under recent state ADU law; City of Las Vegas requires a special-use permit (entitlement ~2–4 months) before a building permit. | Restricted | Nevada has NO statewide ADU mandate. Clark County (unincorporated) permits "Accessory Living Quarters" largely by right under Nevada’s 2025 ADU law (SB 396), but the City of Las Vegas treats ADUs as a conditional/special-use permit under LVMC Title 19. Verify the exact entitlement path for your jurisdiction. Exempt: Clark County allows one ADU per lot with a single-family residence; size tied to a % of the primary dwelling (state law). |
| Oklahoma | Permit required | city | Valuation-based building + trade permits per the local fee schedule. | Plan review; timeline varies by city (OKC full review several weeks for ADU/accessory dwelling). | Restricted | Oklahoma has no statewide ADU law. Accessory dwelling units / apartments are permitted through local zoning in cities like Oklahoma City and Tulsa, often with conditions (setbacks, parking, owner-occupancy). Verify the specific district allowances with the city. Exempt: Local zoning controls size/number of accessory dwelling units. |
| Oregon | Permit required | city | Valuation-based building + trade permits per the local fee schedule. | Plan review; Portland and other cities review ADUs under standard residential review (weeks). | Generally allowed | Oregon’s HB 2001 (2019) requires cities (generally those over 10,000 population) to allow accessory dwelling units in single-family zones, so ADUs are broadly permitted statewide. Local zoning still sets size, setbacks, parking, and owner-occupancy rules — verify with your city. Exempt: Oregon HB 2001 requires most cities to allow ADUs in single-family zones (size/number set locally). |
| Rhode Island | Permit required | city | Rhode Island statewide valuation-based fee formula (Providence minimum permit fee $125). | Plan review; timeline varies by city (Providence 5–15 business days for most reviews). | Generally allowed | Rhode Island’s statewide ADU law requires every municipality to allow accessory dwelling units by right in single-family and two-family zones, so ADUs are broadly permitted. Local zoning still sets size, setbacks, parking, and owner-occupancy rules — verify with your city. Exempt: Rhode Island requires municipalities to allow ADUs by right in single- and two-family zones; size/number set locally. |
| South Carolina | Permit required | city | Valuation-based building + trade permits per the local fee schedule. | Plan review; Charleston requires a full permit package (site plan, floor plans, often a floodplain elevation certificate). | Generally allowed | South Carolina has no statewide ADU law, but many cities (e.g., Charleston) allow accessory dwelling units in residential zones by local ordinance. Verify the specific district allowances (setbacks, parking, flood/storm requirements) with your city. Exempt: South Carolina has no single statewide ADU mandate; local zoning controls size/number of ADUs. |
| South Dakota | Conditional | city | Valuation-based; set by the issuing city. | Plan review handled by the local building department. | Generally allowed | South Dakota has no statewide building code and no state ADU law. Sioux Falls and Rapid City allow ADUs by local ordinance; many rural counties have no building department at all. Zoning approval (use, setbacks, parking) is typically required before the building permit. Exempt: Local zoning sets lot-coverage, setback, and size limits. |
| Utah | Conditional | city | Valuation-based; set by the city under the statewide code. | Plan review through the city (SLC first review ~14 business days). | Generally allowed | Utah follows the statewide Utah Construction Code (IRC-based). ADU allowances are set by local zoning; construction must meet all IRC standards. Local jurisdictions cannot enforce rules more restrictive than the state code (Utah Code Title 15A). Exempt: Local zoning sets size, setback, and parking limits; state law supports ADU by right in many cases. |
| Vermont | Conditional | city | Valuation-based where a building department enforces (e.g., Burlington). | Plan review through the enforcing town (Burlington reviews via Permitting & Inspections). | Generally allowed | Vermont has NO statewide building code for owner-occupied 1–2 family homes — code enforcement is opt-in by town (≈93 opted in, 82 opted out, 266 exempt as of 2020). Burlington enforces the 2025 Vermont Fire & Building Safety Code (2021 IRC). Verify with your town. Exempt: Local zoning sets size, setback, and parking limits. |
| West Virginia | Conditional | city | Valuation-based per the city Schedule of Permit Fees (fees waived for total job cost ≤ $2,500). | Plan review through the city building department. | Generally allowed | West Virginia has a mandatory statewide State Building Code based on the 2018 IRC with state amendments, adopted by the State Fire Commission. ADU allowances are set by local zoning. Exempt: Local zoning sets size, setback, and parking limits. |
| Wyoming | Conditional | city | Valuation-based where a building department enforces (e.g., Cheyenne). | Plan review through the local building department. | Generally allowed | Wyoming has NO mandatory statewide residential building code — Cheyenne, Casper, and other cities adopt the IRC locally (Cheyenne is on the 2024 I-Codes). Much unincorporated county land has no building permit at all. Verify with your local building department. Exempt: Local zoning sets size, setback, and parking limits. |