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

Yes. Franklin County requires a building permit before construction of a permanent structure or an addition to an existing structure begins, and each structure needs its own permit¹. Mobile homes, manufactured homes, and permanently affixed decks or porches are among the covered projects¹. A portable building, portable carport, or other portable structure smaller than 12 by 14 does not require the county permit¹. The building-permit fee is $50, payable to the Supervisor of Assessments; agricultural uses of land or buildings do not pay that fee, but the exception does not waive the permit requirement^1,2. Illinois's statewide building-code baseline has applied since 2025, including in jurisdictions without a locally adopted code³. Franklin County says the permit is issued within 30 days after all facts and pertinent data are properly presented².

Franklin County uses the Supervisor of Assessments rather than a separately named building department for building-permit applications, and the County Engineer approves every permit². The office is in the Franklin County Campbell Building, 901 Public Square, Benton, Illinois, and its phone number is (618) 435-9800¹⁰. Submit a separate application for each structure; once all facts and pertinent data are properly presented, the county's stated issuance period is 30 days². For unincorporated parcels, the County Engineer also checks building permits for floodplain compliance, but that review does not establish a general inspection program for all construction¹¹. Ask the Supervisor of Assessments which code path and local inspections apply; the statewide baseline is confirmed, but Franklin County's own adopted code edition, general inspection schedule, and occupancy-certificate process could not be confirmed^3,10.

Franklin County's countywide zoning status is unconfirmed; no official county zoning ordinance or clear statement that the county has no zoning was confirmed⁵. Do not treat that gap as permission for a particular use, setback, building height, minimum home size, or lot layout⁵. Illinois counties can establish setback lines and regulate building height through local zoning districts, so any actual dimensional limit would come from the applicable local rules¹². The county board lists zoning among its Public Safety committee responsibilities, and its permit notice distinguishes cities, towns and villages that do not have zoning or city ordinances, so land-use controls differ by locality¹. For property inside a city, town or village without zoning or city ordinances, the county states that a building permit is required¹. Ask the Supervisor of Assessments which land-use authority applies to the parcel before fixing a site plan¹⁰.

The Franklin-Williamson Bi-County Health Department administers local sewage review and enforcement under local ordinances incorporating the state code, while Illinois retains statewide authority⁴. Private systems serving 15 people or fewer need a permit before construction for new and major-renovation work, and the permit fee is $150^6,7. The application needs a 911 address, and the department must be notified 48 hours before construction begins after the permit is issued⁶. A private-system permit may be refused if sanitary sewer service adjoins the property or a practical permitted connection is available within 300 feet for a single-family home¹³. A septic permit is valid for 12 months from issuance, and the Board of Health acts on applications within 15 days¹³. Routine cleaning or replacing a septic-tank cover does not need a construction permit¹³. The department inspects for compliance with approved plans and code; a homeowner-installed system also needs a site inspection before permit issuance⁴. Only about 3.1% of county soils are rated without severe limitations for a conventional drain field, so confirm feasibility before fixing the house site¹⁴.

Franklin County has not confirmed a rule allowing or prohibiting long-term RV occupancy, temporary camping, or tiny-home occupancy on an individual private parcel⁵. The county's permit rule still applies to permanent structures, additions, mobile homes, and manufactured homes, while only portable structures smaller than 12 by 14 receive the stated size exception¹. Illinois campground licensing addresses regulated campgrounds and temporary RV parking there, not the separate question of living in an RV on your own land¹⁵. Before buying or moving a unit onto land, ask the Supervisor of Assessments whether the proposed structure and use need county approval, and ask Environmental Health how wastewater will be approved^4,10. A manufactured home also remains subject to Illinois installation requirements and any applicable local zoning, floodplain, and utility rules¹⁶.

1. Confirm whether the parcel is unincorporated or inside a municipality, and ask the Supervisor of Assessments which land-use rules apply because countywide zoning is unconfirmed^5,10.
2. Check sewer availability with Environmental Health and obtain septic approval before construction if a private system is allowed^6,13.
3. Submit a separate building-permit application for each permanent structure and pay the $50 fee unless the agricultural-use fee exception applies^1,2.
4. Confirm the applicable code path and inspections; Illinois's statewide baseline applies, while Franklin County's local code edition and general inspection schedule could not be confirmed^3,10.
5. Obtain the County Engineer's approval and, for development in an unincorporated floodplain, a floodplain-development permit^2,17.
6. Obtain a private-well permit before construction if the property will use a new well⁴.
7. Identify the road authority; Franklin County provides one 20-foot entrance per property on county highways, while state-highway work needs an IDOT permit^11,18.

Start with sewer availability and septic feasibility: a nearby sanitary sewer can prevent private-system approval, and only about 3.1% of county soils are rated without severe limitations for a conventional drain field^13,14. Check the house site for floodplain constraints because development in an unincorporated floodplain needs a permit from the County Engineer¹⁷. Identify the road authority before planning access; Franklin County provides one 20-foot entrance per property on county highways, while state-highway work needs an IDOT permit^11,18. Land transfers must follow the Franklin County Subdivision Ordinance and Illinois Plat Act, and a transfer outside a city or subdivision lot needs the Supervisor of Assessments' approval for compliance¹⁹. A new private well needs a permit before construction and will be inspected⁴. Reported farmland value is about $5,677 per acre, while the median property-tax bill is about $1,316 a year at an effective rate near 1.5%¹⁴.