For land outside the cities, Montgomery County Planning and Zoning, 310 Salisbury Street, Suite D, Montgomery City (573-564-2142), issues construction permits under the county Zoning Order for structures 10 by 10 ft or larger. The county’s permit brochure prices a house, mobile or modular home or commercial building at $0.10 per sq ft of total floor area, garage, carport and finished basement included, so a house with 2,000 sq ft in all is $200; the permit lasts one year and the fee doubles if building starts first. A septic permit from the Montgomery County Health Department comes before the construction permit for a new system.
What needs a county construction permit
Permit needed
- New homes, including mobile and modular homes
- Commercial and industrial buildings, including data centers
- Storage buildings and detached garages 10 by 10 ft or larger
- Portable carports
- Additions and changes in the use of land or of a building
- New septic systems (Health Department permit)
No permit
- Agricultural buildings, with last year’s Schedule F tax form to prove farm use
- Fences and decks
- Swimming pools
- Gazebos and picnic shelters
- Open porches
The Zoning Administrator decides whether a building counts as agricultural. Since January 2007 the county has not permitted a mobile home made more than 10 years before the application date, and the title or another manufacturer document must show its age.
Montgomery County building department: who handles permitting
Planning and Zoning is open in the office Monday to Friday, 8 a.m. to 4 p.m. (planningzoning@mcmo.us). It administers the county Zoning Order, with agricultural, residential, commercial, industrial and Rural Village districts, and its Planning and Zoning Commission meets monthly. The Rural Villages are Danville, Mineola, Big Spring, Americus, Gamma, Buell, Marling, Price’s Branch, Bluffton, Starkenburg, Pinnacle Lake and Golden Eagle Reserve. Septic permits come from the Montgomery County Health Department, 400 Salisbury Street (573-564-2495), and street addresses from the county E-911 Addressing office (573-564-2284).
Short on time to read all of this?
Get a free quote →The incorporated places permit work inside their own limits. Populations are Census Bureau Vintage 2025 estimates.
| Place | Who permits building work |
|---|---|
| Montgomery City (2,782) | The City Administrator/Clerk handles building code and ordinance questions; City Hall 573-564-3160 |
| Jonesburg (864) | City Hall approves building permits: print the residential, commercial or miscellaneous application, attach plans and surveys, and drop it off at 106 West Booneslick Road (636-488-5508); approval takes a couple of days |
| New Florence (650) | City code enforcement, on the City’s building permit application; contractors need a City business licence first. The posted City Code adopts the 2003 International Building and Residential Codes. City Hall, 217 South Main Street, 573-835-2106 |
| Wellsville (1,012), Bellflower (337), High Hill (186), Middletown (169), Rhineland (138), McKittrick (80) | The published sources do not say; ask the town clerk |
Construction permit application
The county’s construction permit application covers new buildings, enlarging or altering an existing structure, moving a structure, a new sewage system under the On-Site Sewage System Ordinance, and a change in the use of land or of a building. It assigns both a construction permit number and a certificate of occupancy number. Bring to the Planning and Zoning office:
Not sure this scope needs a permit?
Get a free quote →- The Assessor’s property record card for the parcel
- A copy of the deed
- The physical address from E-911 Addressing
- A site plan with all setbacks and existing structures, utilities, water supply, sewage system, drainage and driveways
- A floor plan on letter-size paper with total square footage, for new homes and mobile or modular homes
- The septic permit receipt from the Health Department, if a new system is being installed
- Elevations of the building and its utilities if the site is in the Flood Plain Overlay District
Montgomery County permit fees
| Permit | Fee |
|---|---|
| House, mobile or modular home, commercial building | $0.10 per sq ft |
| Storage building, detached garage or portable carport | $0.05 per sq ft, $15 minimum |
| Agricultural building | Exempt |
| Started before the permit was issued | Double the fee |
The square footage counts every level, including the garage, carport, finished basement and loft. For example, a house with 2,000 sq ft in all is $200 and a 24 by 30 ft (720 sq ft) detached garage is $36. Permits are valid for one year from the date they are bought.
Septic systems
The Montgomery County Health Department is the county’s onsite wastewater authority under its own ordinance, in force since September 2011. Every new septic installation needs a permit whatever the acreage, and a septic tank must come before any lagoon. Adding a bedroom, bathroom or kitchen, or replacing one structure with another, needs a soil test and site check by a licensed installer, with the results sent to the County Sanitarian.
Rather talk it over?
Call 1-855-478-4290 →How to get a Montgomery County construction permit
Check that the parcel is outside the cities and that the use is allowed in its zoning district; some uses need a conditional use hearing.
Request the address from E-911 Addressing and, for a new system, the septic permit from the Health Department.
Draw all setbacks and existing structures, and show flood elevations if the site is in the Flood Plain Overlay District.
Bring the record card, deed, plans and fee to 310 Salisbury Street, Suite D, before starting work.
The construction permit is valid for one year from purchase.
Floodplain, data center and zoning updates
Floodplain: the county takes part in the National Flood Insurance Program, with flood maps dated May 18, 2009. Building sites in the Flood Plain Overlay District need flood elevations on the application, and the Emergency Management office, 250 Pickering Street, Montgomery City (573-564-2283), is the county’s floodplain contact.
Rather not deal with the Montgomery County building department?
Get a free quote →Data centers: the county’s March 30, 2026 FAQ says data centers are permitted by right on commercial or industrial land after a Planning and Zoning administrative review, need a conditional use hearing on agricultural land and are not allowed in Rural Village or residential districts. Construction permits for two data center campuses on the Mega Site at I-70 and Highway 19 near New Florence were issued in February and March 2026, and in October 2026 the county posted a map of a proposed Amazon campus on Tree Farm Road.
Missouri building code
Missouri has no mandatory statewide building code for private construction: a county, fire protection district or municipality may adopt one (usually by reference under RSMo 67.280), and in parts of the state none has. Building codes in Missouri
Montgomery County permit FAQs
Who issues building permits in unincorporated Montgomery County?
Montgomery County Planning and Zoning, 310 Salisbury Street, Suite D, Montgomery City (573-564-2142), issues construction permits under the Zoning Order.
How much is a construction permit for a house?
$0.10 per sq ft of total floor area, garage, carport and finished basement included; a house with 2,000 sq ft in all is $200. The fee doubles if construction starts before the permit is bought.
Do I need a permit for a shed, deck or fence?
Storage buildings 10 by 10 ft or larger need one ($0.05 per sq ft, $15 minimum). Fences, decks, pools, gazebos and open porches do not.
Are farm buildings exempt?
Yes, buildings used only for agriculture are exempt, but you must show last year’s Schedule F to prove farm use.
Who issues septic permits?
The Montgomery County Health Department, 400 Salisbury Street, Montgomery City (573-564-2495). Every new septic system needs a permit.
Want this handled start to finish?
Get a free quote →Are data centers allowed in Montgomery County?
On land zoned commercial or industrial, yes, after a Planning and Zoning administrative review; agricultural land needs a conditional use hearing, and Rural Village and residential districts do not allow them.
Montgomery County permit search and official resources
- Montgomery County Planning and Zoning
- Montgomery County construction permit brochure
- Montgomery County construction permit application
- Montgomery County Mega Site and data center FAQ (March 2026)
- County Commission agenda, October 26, 2026
- Montgomery County departments and phone numbers
- Missouri DHSS onsite wastewater permit contacts: Montgomery County
- FEMA Community Status Book: Missouri
- Montgomery City building inspection contact
- City of Jonesburg building permit applications
- City of New Florence forms and permit applications
Inspections are where schedules slip.
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Read guide →This guide is provided by Alliance Permitting for general information about Montgomery County permitting. Requirements, fees, and procedures change; confirm details with the permitting authority before relying on them.