Building permits, zoning and land rules in Montgomery County, Illinois

Unincorporated Montgomery County does not issue a building-code permit, but construction and improvements require a Structural Improvement notification for assessment purposes¹. File the notification before construction; failure to file can bring a fine of up to $500 per day¹. The completed worksheet satisfies the county notification process but does not replace city, township, subdivision or state requirements⁷. Illinois has imposed statewide baseline building-code requirements since 2025, including a framework for jurisdictions that have not adopted a local building code⁸. We could not confirm Montgomery County's countywide building-code adoption or ordinary building-inspection program, so ask the Supervisor of Assessments what your project must submit and which authority will inspect it¹.

Start with the Montgomery County Supervisor of Assessments at (217) 532-9595 or assessor@montgomerycountyil.gov, at 1 Courthouse Square Room 201, Hillsboro, IL 62049¹. That office receives the Structural Improvement notification; Montgomery County describes the filing as an assessment notice, not a building-code permit¹. When a rural project needs a 911 address, obtain the building-address permit first; the assessment office verifies the parcel and routes the application through highway, health and 911 review⁹. Inside a city or village, ask its clerk which municipal building permits and zoning approvals apply². The Montgomery County Health Department still handles the local septic permit, inspection and final approval under statewide IDPH regulation³.

Rural, unincorporated Montgomery County has no county zoning ordinance or rural county zoning districts². County zoning therefore sets no minimum dwelling size, general minimum lot size, setback, lot-coverage limit or building-height limit there². Subdivision plats are different: preliminary plats generally require lots of at least 6,000 square feet and 50 feet wide at the building line, subject to the ordinance's stated exception¹⁰. County zoning also does not restrict a tiny home, manufactured home or accessory dwelling in rural unincorporated areas, but septic, subdivision and other rules remain². Inside a municipality, ask its clerk about local zoning².

IDPH regulates private sewage disposal statewide, while the Montgomery County Health Department administers the local septic permit, inspection and final-approval process³. Obtain the county septic permit before installation; it lasts one year, and the application states a $50 fee⁴. Request inspection two working days before installation begins and obtain final Health Department approval before covering any part of the system⁴. For a subdivision using private sewage systems, the preliminary plat must include a licensed soil classifier's report and identify the proposed system for each lot¹⁰. Conventional septic feasibility deserves early attention because only about 4.9% of county soils are rated without severe limits for a conventional drain field¹¹. Approved alternative toilets do not eliminate the need to handle other domestic wastewater through a conventional private sewage system¹².

Rural, unincorporated Montgomery County has no county-zoning restriction on RV occupancy or temporary camping². That answer is limited to county zoning: septic, health, building, access and other requirements can still determine whether a particular setup is lawful or workable². A tiny home likewise faces no county-zoning restriction on occupancy or minimum dwelling size there². A manufactured home faces no rural county-zoning restriction, while Illinois installation and licensing requirements still apply^2,13. Before placing an RV, ask the Health Department how wastewater will be handled⁴. Inside a city or village, obtain the municipality's own zoning answer rather than relying on the rural county rule².

1. Confirm whether the parcel is rural unincorporated land or inside a city or village; ask the municipal clerk about city or village building permits and zoning approvals².
2. Contact the Supervisor of Assessments at (217) 532-9595 and file the Structural Improvement notification before construction¹.
3. Ask the assessment office to confirm the applicable Illinois baseline-code path and any inspection or occupancy requirements, because county adoption, inspection and certificate-of-occupancy details remain unconfirmed^1,8.
4. Obtain the Montgomery County Health Department septic permit, request inspection two working days before installation and secure final approval before covering the system^3,4.
5. Obtain the required private-well permit and confirm plan review and inspection with IDPH or the local health department⁶.
6. If a rural 911 address is needed, obtain the building-address permit so assessment can route the review through highway, health and 911 offices⁹.
7. Confirm subdivision approval when dividing land, and get an IDOT permit before work in a state-maintained road right-of-way^10,14.

Verify the parcel's municipal status first because rural land has no county zoning ordinance, while a city or village may impose its own zoning requirements². Test septic feasibility early: only about 4.9% of county soils are rated without severe limits for a conventional drain field, and a county permit and final approval are required^4,11. If the property is being subdivided, confirm the preliminary-plat standards and sewage documentation before relying on the general absence of a county zoning lot minimum¹⁰. Confirm the private-well permit path before drilling⁶. A rural electric connection may require a verified 911 address, but we could not confirm a countywide water or sewer connection rule⁹. Property taxes average about 1.7% effectively, with a median annual bill near $1,758, while reported farmland value is about $8,961 per acre¹¹.