Building permits, zoning and septic rules across Illinois counties

Illinois has 20 counties that do not require a residential building permit in unincorporated areas, including Brown County, Schuyler County, Crawford County, Clark County, Clay County, Wayne County, Greene County, Effingham County¹. Another 23 counties require a building permit only in some cases, while 59 require a residential building permit⁶. Use the Illinois no-building-codes county list to compare counties by their building-permit answers¹.

Illinois's statewide building-code baseline took effect in 2025, including requirements for jurisdictions without adopted local codes, so the absence of a county building permit does not remove the applicable state code requirements¹⁰. The State does not issue building permits for privately funded construction; any required building permit comes through the local government¹¹. CDB's Building Codes and Regulations office provides local code directories; ask the local code official which requirements apply to the proposed home¹⁰.

Illinois has 23 counties without countywide zoning, including Brown County, Schuyler County, Crawford County, Clark County, Clay County, Wayne County, Greene County, Richland County². Countywide zoning is present in 65 counties, and we could not confirm the zoning answer in 14 counties⁶. Compare the Illinois counties with no zoning before choosing a parcel².

Illinois has 19 counties combining no residential building permit with no countywide zoning; the combined county list helps narrow that search⁷. Where county zoning applies, setback distances depend on the applicable district or local ordinance, and agricultural buildings may still have to meet setback lines¹². Even in a county without zoning, a new private sewage disposal system needs plan approval before construction³.

Illinois septic authority is divided among county offices in 74 counties, multi-county health districts in 26, and the state agency in 2; Southern Seven Health Department is the most frequently named district authority⁶. IDPH regulates private sewage disposal and reviews plans alongside local health agencies¹³.

Before building a new septic system, obtain plan approval from IDPH or the applicable local authority and submit site information, bedroom count or design volume, and soil or percolation information³. Notify that authority at least 48 hours before installation, repair or modification begins³. Ask the health authority serving the parcel for its septic application and fee before ordering equipment¹³.

Illinois permits specified human-waste alternatives, including compost and incinerator toilets, but other domestic wastes still require conventional private sewage disposal under that rule¹⁴. Eligible surface-discharging systems also face Illinois EPA permit conditions, including periodic inspection, monitoring and reporting¹⁵.

Illinois RV occupancy has an answer in 36 counties: 9 allowed, 5 temporary-only, 16 limited and 6 prohibited; the other 66 are unconfirmed⁴. The first counties with an allowed county-zoning answer are Richland County, Effingham County, Hancock County; these answers concern county zoning and do not waive sanitation or other applicable requirements⁴. Browse the Illinois RV-living county list for those county-specific conditions⁴.

Illinois tiny-home occupancy has an answer in 23 counties: 11 allowed and 12 limited, with 79 unconfirmed⁵. The first allowed entries are Schuyler County, Richland County, Effingham County, with the stated allowances limited to county land-use zoning⁵. Use the Illinois tiny-home county list and ask the parcel's local building and zoning office about the proposed unit and occupancy⁵. Illinois's campground law addresses overnight camping in regulated campgrounds; that scope does not establish permission to reside in an RV on a private residential parcel¹⁶.

The highest Bolthole Index scores belong to Brown County, Schuyler County, Crawford County, Clark County, Clay County, Wayne County, Fulton County, Greene County⁶. Brown and Schuyler lead at 83 out of 100; both have no residential building permit and no countywide zoning, with septic authority at the county level⁶. Fulton differs: its building-permit requirement is limited to some cases, county zoning applies, and septic authority is a health district⁶.

The median county farmland value across Illinois is $8,250 per acre, while Pope County has the lowest listed value at $4,224 per acre; these are farmland values rather than an asking price for a particular homesite⁶. The median county effective property-tax rate is 1.8%, and the median county property-tax bill is $2,363 annually; neither figure is a parcel-specific tax estimate⁶. Compare the county's building, zoning and septic answers alongside land cost when selecting a place to investigate⁶.

Illinois requires a permit from IDPH or an approved local health department before constructing, modifying or sealing a water well⁹. Water-well permit fees may not exceed $100, and the permit becomes void if construction has not begun within a year of issuance⁹. The application includes well location and distances to contamination sources such as septic tanks and seepage fields, so plan the well and sewage layout together before work starts⁹.

The northeastern Illinois deep bedrock aquifer is identified as declining or over-appropriated in Will County, Kendall County and Kane County¹⁷.

Qualifying owner occupants can perform plumbing on a single-family residence intended for their own occupancy, subject to state plumbing standards, inspection and restrictions on hired assistance⁸. Local plumbing permits may still be required; the owner-occupant provision does not establish a general exemption from building permits¹⁸.