Ralls County is zoned, and its Zoning Order (effective January 1, 2025) requires a Construction Permit before anyone builds, enlarges, alters or moves a building anywhere in the unincorporated county, including modular and manufactured homes. Permits come from Ralls County Planning & Zoning (573-822-4608); applications are taken by appointment only, booked through the Road & Bridge office at 573-985-2011. A new home is a flat $250 under the fee schedule revised January 12, 2026, and a moratorium blocks applications for large economic development projects and data centers until September 1, 2027.
Ralls County building department: who handles permitting
Ralls County Planning & Zoning issues Construction Permits for all unincorporated land, including unincorporated villages. Applications are taken by appointment only; call 573-985-2011, the number the county lists for the Road & Bridge office, to book one. Inside the cities, the city’s own rules apply. Populations are Census Bureau Vintage 2025 estimates for the part of each place in Ralls County.
Short on time to read all of this?
Get a free quote →| Place | Who permits building work |
|---|---|
| New London (981) | The Building Inspector, a city officer designated by the Mayor, issues permits for $10; plans and a statement of materials go in duplicate. City clerk 573-985-4041 |
| Perry (686) | The City issues building permits for $50 per structure, valid for a year; $75 penalty if work starts first. City clerk 573-565-3131 |
| Center (542) | The City requires a building permit for any type of construction under its zoning regulations; City Hall, 103 S. Public St.; 573-267-3331 |
| Hannibal (283; 16,521 in Marion County) | City Building Inspector’s Office, City Hall, 320 Broadway; 573-221-0111. Its online portal asks applicants whose address may fall under Ralls County zoning to call before applying |
| Rensselaer (249) | The published sources do not say; the county lists a village contact at 573-248-6525 |
| Monroe City (30; 2,175 in Monroe County) | City building official under the city code; City Hall 660-735-4585 |
| Vandalia (0 in Ralls; 3,029 in Audrain County) | The City of Vandalia’s Building Permit Commissioner |
Ralls County permit fees
The fee schedule in the Zoning Order was revised on January 12, 2026. Fees are reviewed on the first Wednesday of November each year, and any change takes effect the following January 1. Only checks are accepted, payable to the Ralls County Treasurer.
| Permit | Fee |
|---|---|
| New home | $250 for any square footage, covering everything under the roof |
| Addition to a home | $100 |
| Non-residential or commercial building | $0.50 per sq ft, $1,000 minimum; $0.40 per sq ft over 10,000 sq ft |
| Accessory building over 100 sq ft | $50 |
| Agricultural building over 100 sq ft | $25 |
| Concentrated animal feeding operation | $500, renewed every five years |
| Building without a permit | Double the permit fee |
Not sure this scope needs a permit?
Get a free quote →Permits expire after one year. Buildings of 100 square feet or less are exempt from the permit requirement.
Application, lot size, septic and flood rules
What to submit: names and contact details for the owner and every professional on the job, site plans and construction plans, and a site plan showing lot dimensions, soil information, existing and proposed buildings, drainage and sewage disposal, and water supply. The septic design must meet the On-Site Domestic Wastewater Treatment Systems Ordinance (Appendix E), and a copy of the sewer application and permit goes in with the Construction Permit application.
Lot size: any parcel surveyed after May 12, 2025 on which a home is built must be at least 3 acres. The 3-acre minimum does not apply to a single-family home connected to an existing central sewer system approved by the Missouri Department of Natural Resources; bring a letter from the sewer provider. The minimum is also waived for a one-time transfer of at least 1 acre to each immediate family member (spouse, son, daughter, sister, brother, father, mother or grandchild), provided the owner keeps at least 3 acres; the recipient must hold the land for a year before it changes hands again.
Septic systems: the Ralls County Health Department (405 W. First St., New London; 573-985-7121) requires a permit for every new system, regardless of lot size, and for any repair, replacement or upgrade. The permit fee is $115, waived for upgrades and repairs; the application needs a soil test by a registered soil scientist and a registered installer’s signature, and the department must be told between 48 and 4 hours before installation starts. This health permit is separate from the Planning & Zoning wastewater permit.
Rather talk it over?
Call 1-855-478-4290 →Floodplains and roads: the county Road Supervisor is also the floodplain administrator (573-406-9611), and the Zoning Order has a Floodplain Overlay District. Ralls County takes part in the National Flood Insurance Program with maps dated April 19, 2010; New London and Hannibal do too, while FEMA lists Perry and Rensselaer as not in the program. Road & Bridge (573-985-2011) maintains about 451 miles of county road, installs driveway pipes and handles road use agreements and utility permits.
Getting a Ralls County Construction Permit
Confirm the land is outside city limits and, for a new home, at least 3 acres if surveyed after May 12, 2025.
Apply to the Ralls County Health Department and keep a copy of the sewer application and permit.
Call 573-985-2011 and bring the site plan, construction plans and septic paperwork to Planning & Zoning.
Pay the fee to the Ralls County Treasurer; the permit is valid for one year.
Contact the Road Supervisor for floodplain questions and for driveway pipes on county roads.
Rather not deal with the Ralls County building department?
Get a free quote →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
Ralls County permit FAQs
Do I need a permit to build in rural Ralls County?
Yes. A county Construction Permit is required for new buildings, additions, alterations, moved buildings and changes of land use anywhere in the unincorporated county. Buildings of 100 square feet or less are exempt.
How much is a building permit for a new house in Ralls County?
$250 regardless of size, or $100 for an addition, paid by check to the Ralls County Treasurer.
What is the minimum lot size for a new home?
3 acres for land surveyed after May 12, 2025, unless the home connects to a DNR-approved central sewer system or the lot is a one-time family transfer of at least 1 acre.
How long is a Ralls County permit good for?
One year from issue.
Can a data center be built in Ralls County now?
Not before September 1, 2027 unless the County Commission grants an exception; until then the county will not process applications for data centers or economic development projects of 50 acres and $3 million or more.
Who issues permits in New London and Perry?
Each city issues its own: New London’s Building Inspector charges $10, and Perry charges $50 per structure.
Want this handled start to finish?
Get a free quote →Ralls County permit search and official resources
- Ralls County Planning & Zoning
- Ralls County Zoning Order with fee schedule (January 2026)
- Ralls County economic development and data center moratorium
- Ralls County Road & Bridge and floodplain administrator
- Ralls County communities and city contacts
- Ralls County Health Department onsite sewage permits
- Ralls County Health Department procedures to obtain a septic permit
- SEMA emergency management and floodplain contacts: Ralls County
- FEMA Community Status Book: Missouri
- New London City Code on eCode360
- Perry City Code on eCode360
- City of Center City Hall information
Inspections are where schedules slip.
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Read guide →This guide is provided by Alliance Permitting for general information about Ralls County permitting. Requirements, fees, and procedures change; confirm details with the permitting authority before relying on them.