How much does a building permit cost in unincorporated Mercer County, MO?

The minimum permit fee is Public fee schedule for ordinary building permits was not clearly found. The ordinance states amendment or conditional use applications are $200, with $150 annual renewal. Fees are calculated as: Flat fees were found for amendments and conditional use permits. Specific building permit fee formulas were not clearly published in the public text reviewed. Plan check fee: Not clearly published in the public materials reviewed.

What work is exempt from building permits in unincorporated Mercer County, MO?

The following work is generally exempt: Routine maintenance or repair of buildings, structures, or equipment, such as repainting, re-roofing, or insulating a building; Alterations costing less than $1,000 to existing buildings, so long as they do not change the exterior dimensions of the enclosed portion; Construction of a service connection to a municipally owned and operated utility; Agricultural uses; Small wind energy systems used for agricultural purposes are exempt from zoning and building fees.

How do I schedule a building inspection in unincorporated Mercer County, MO?

Inspections can be scheduled via: Public inspection scheduling methods were not clearly published for general county permits.

County Building Permits

Mercer County, MO - 2026 Building Permit Guide

How to apply for a building permit in unincorporated Mercer County, Missouri. Permit authority, application steps, fees, and inspection requirements.

Missouri Updated March 2026

Permit Authority

Mercer County zoning applies to unincorporated portions of the county. The public county ordinance requires a zoning certificate before buildings or structures are constructed, reconstructed, erected, moved in, or altered in unincorporated Mercer County

Department: Mercer County Zoning Officer / Mercer County Board of Commissioners
Address: 802 E Main St, Princeton, MO 64673 (county courthouse mailing/contact address)
Phone: 660-748-3425
Email: mcclerk@grm.net
Website: https://cms8.revize.com/revize/mercer/Ordinances/Mercer%20County%20Zoning%20Ordinances.pdf

Online Permit Portal

Open No public online permit portal found for county building permits

Platform: None found • Account required: No • Submission: In-person only

Additional resources:

Application Process

Confirm the site is in unincorporated Mercer County and determine whether the work is exempt from a zoning certificate
Prepare the county form and any supporting plats or drawings the Zoning Officer requires
Submit the application to the Mercer County Zoning Officer
The Zoning Officer examines the application for compliance with the Mercer County Zoning Resolution
If approved, obtain the zoning certificate and any related county approval before starting work
For qualifying projects such as mobile/manufactured/modular homes, solar facilities, or wind energy systems, obtain the separate county building permit required by ordinance before installation or construction

Typical processing time: Not clearly stated for general county zoning certificate requests. For wind energy systems, the Code Administrator should issue or deny a permit within one month of receipt

Source: Mercer County Zoning Officer / Mercer County Board of Commissioners

General Requirements

The county ordinance requires a zoning certificate for any building or structure constructed, reconstructed, erected, moved in, or altered in unincorporated Mercer County. Separate building permits are also required for newly installed or replacement mobile/manufactured/modular or panelized homes, wind energy systems, and solar energy facilities

Required Documents

When a permit is required: The county ordinance requires a zoning certificate for any building or structure constructed, reconstructed, erected, moved in, or altered in unincorporated Mercer County. Separate building permits are also required for newly installed or replacement mobile/manufactured/modular or panelized homes, wind energy systems, and solar energy facilities
Required documents: County form, and at least for some projects plats or drawings showing building location, dimensions, and lot lines. Wind energy systems require two copies of a drawing, engineer-sealed construction plans, special inspections, and FAA lighting permit if needed
Permit validity/expiration: General conditional use permits are valid for 12 months unless renewed. Building permits for mobile/manufactured/modular or panelized homes are valid for 12 months. Wind conditional use permits expire if not installed and functioning within 1 year or if unused for 12 months
Owner-builder rules if available: No public owner-builder rule was found in the county ordinance excerpts reviewed
Contractor license requirements: No county contractor licensing rule was found in the public materials reviewed
Building code adopted: Mercer County does not appear on Missouri's county building code list for an adopted county residential or commercial code. The public ordinance itself governs zoning and selected permit categories

Permit validity: General conditional use permits are valid for 12 months unless renewed. Building permits for mobile/manufactured/modular or panelized homes are valid for 12 months. Wind conditional use permits expire if not installed and functioning within 1 year or if unused for 12 months
Building code: Mercer County does not appear on Missouri's county building code list for an adopted county residential or commercial code. The public ordinance itself governs zoning and selected permit categories
Owner-builder: No public owner-builder rule was found in the county ordinance excerpts reviewed
Contractor requirements: No county contractor licensing rule was found in the public materials reviewed

Fees

Minimum permit fee: Public fee schedule for ordinary building permits was not clearly found. The ordinance states amendment or conditional use applications are $200, with $150 annual renewal
Plan check fee: Not clearly published in the public materials reviewed
Permit fee formula: Flat fees were found for amendments and conditional use permits. Specific building permit fee formulas were not clearly published in the public text reviewed
Reinspection fee: The ordinance references fines and costs for violations, but no standard reinspection fee schedule was found
Payment note: No online county payment workflow was found in the public sources reviewed

Fees change. Verify current amounts at the official fee schedule.

Work That Does NOT Require a Permit

Contact the Mercer County Zoning Officer / Mercer County Board of Commissioners to confirm whether your project requires a permit before starting work.

Inspections

How to Schedule

Public inspection scheduling methods were not clearly published for general county permits ()

Inspection hours: Not found

Typical inspection sequence: For wind energy systems, the county Code Administrator may inspect compliance and must verify application materials, road agreements, restoration agreements, and other ordinance conditions before approval

Additional Resources

Building code: Mercer County does not appear on Missouri's county building code list for an adopted county residential or commercial code. The public ordinance itself governs zoning and selected permit categories
Zoning information: View zoning info
cms8.revize.com
mocounties.com
License lookup guide: Missouri Contractor License Requirements
Contract template: Missouri Homeowner-Contractor Agreement
Missouri hub: Missouri Contractor License & Permit Hub

Information on this page was last verified: March 2026. Permit rules and fees change — confirm current requirements directly with the Mercer County Zoning Officer / Mercer County Board of Commissioners before applying.

Frequently Asked Questions

Mercer County Building Permit FAQ

Do I need a building permit in unincorporated Mercer County, MO?: The county ordinance requires a zoning certificate for any building or structure constructed, reconstructed, erected, moved in, or altered in unincorporated Mercer County. Separate building permits are also required for newly installed or replacement mobile/manufactured/modular or panelized homes, wind energy systems, and solar energy facilities
How much does a building permit cost in unincorporated Mercer County, MO?: The minimum permit fee is Public fee schedule for ordinary building permits was not clearly found. The ordinance states amendment or conditional use applications are $200, with $150 annual renewal. Fees are calculated as: Flat fees were found for amendments and conditional use permits. Specific building permit fee formulas were not clearly published in the public text reviewed. Plan check fee: Not clearly published in the public materials reviewed.
How do I apply for a building permit in unincorporated Mercer County, MO?: 1. Confirm the site is in unincorporated Mercer County and determine whether the work is exempt from a zoning certificate 2. Prepare the county form and any supporting plats or drawings the Zoning Officer requires 3. Submit the application to the Mercer County Zoning Officer 4. The Zoning Officer examines the application for compliance with the Mercer County Zoning Resolution 5. If approved, obtain the zoning certificate and any related county approval before starting work 6. For qualifying projects such as mobile/manufactured/modular homes, solar facilities, or wind energy systems, obtain the separate county building permit required by ordinance before installation or construction
How long does it take to get a building permit in unincorporated Mercer County, MO?: Typical processing time is Not clearly stated for general county zoning certificate requests. For wind energy systems, the Code Administrator should issue or deny a permit within one month of receipt.
What work is exempt from building permits in unincorporated Mercer County, MO?: The following work is generally exempt: Routine maintenance or repair of buildings, structures, or equipment, such as repainting, re-roofing, or insulating a building; Alterations costing less than $1,000 to existing buildings, so long as they do not change the exterior dimensions of the enclosed portion; Construction of a service connection to a municipally owned and operated utility; Agricultural uses; Small wind energy systems used for agricultural purposes are exempt from zoning and building fees.
How do I schedule a building inspection in unincorporated Mercer County, MO?: Inspections can be scheduled via: Public inspection scheduling methods were not clearly published for general county permits.

Need help with your project?

Navigating permits in Mercer County Unincorporated Areas can be complicated.

Jaspector connects you with local experts who can review your scope, verify your contractor, and help you understand what permits your project actually needs.

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Important: This page is an educational resource provided by jaspector.com. It is not legal advice, and it does not substitute for official guidance from the permit authority listed above. Permit requirements, fees, and processes change frequently. Always verify current requirements directly with the issuing department before beginning any construction project. Use of this page does not create an attorney-client relationship. Jaspector assumes no liability for any outcomes arising from reliance on this information.

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