State guide
Illinois
Illinois regulates private sewage disposal primarily through the Illinois Department of Public Health, but local health departments remain central because many counties review plans, issue permits, and inspect installations as IDPH agents or under local ordinance. For surface-discharging private sewage systems needing NPDES coverage, Illinois EPA has a separate permit track.
Checked against official sources on October 4, 2026. Rules and links change; confirm with the office listed before you act.
- Who regulates septic permits
- Illinois Department of Public Health regulates private sewage disposal statewide, while many local health departments review plans, issue permits, and inspect systems as IDPH agents or under local ordinance; Illinois EPA separately handles ILG62 surface-discharge NPDES coverage.
- Who can do the soil or perc test
- For subsurface system design, soil investigations must be based on soil boring data collected by a soil classifier or an Illinois licensed Professional Engineer; certain qualified local health department employees may also conduct soil investigations under the code.
- Official septic permit page
- Official page →
- State fee
- Not published by an official source we could verify. Ask the office.
Official resources in Illinois
Primary state page for private sewage disposal laws, forms, contractor search, and overview of local health agency involvement.
State directory map residents can use to find the local health department that may issue or review septic permits.
Official Illinois EPA page for new and replacement surface-discharging private sewage disposal systems requiring NPDES coverage.
State contractor search linked from IDPH for active private sewage licenses.
Key facts for Illinois
- IDPH regulates private sewage disposal systems with no surface discharge and those discharging treated effluent up to 1,500 gallons per day to ground surface.
- IDPH says about 90 local health agencies also review sewage disposal construction plans, either by local ordinance or as Department agents.
- Illinois code says soil boring data for proposed private sewage systems must be collected by a soil classifier or an Illinois licensed Professional Engineer.
- Illinois code also allows certain local health department employees with stated experience and coursework to conduct soil investigations.
- After January 1, 2014, percolation tests may not be used to determine design requirements for a subsurface system.
- Illinois EPA’s ILG62 general permit applies to new and replacement surface-discharging private sewage disposal systems.
County septic and soil-evaluation offices in Illinois
| County office | city | phone | Details |
|---|---|---|---|
| Coles County Health Department — Private Sewage Systems Coles | Charleston | Not published* | County sewage page explains soil evaluation first, and the program approves plans, performs inspections, and investigates complaints. |
| DeKalb County Health Department — Well & Septic DeKalb | DeKalb | Not published* | County page states septic installations, repairs, and modifications must be done by IDPH licensed septic system installation contractors. |
| Bond County Health Department — Environmental Health Bond | Greenville | (618) 664-1442 ext. 149 | Environmental health page says a permit is required before installing, replacing, or modifying any private sewage disposal system. |
| Crawford County Health Department — Private Sewage Crawford | Robinson | 618-544-8798 | County page says environmental health staff review plans and inspect installations before systems are constructed. |
| Clay County Health Department — Private Sewage Clay | Flora | (618) 662-4406 | County page says construction permits are issued after a plan review application and fee are submitted and approved. |
* Not published: the official page doesn't list it. Call the office to confirm before you rely on it.
What to do next
- Start with the local health department for the county where the property sits, because many permit reviews and inspections are handled locally.
- For a conventional subsurface design, line up a qualified soil classifier or Illinois licensed Professional Engineer before finalizing plans.
- If the proposed system will surface-discharge to waters of the United States, check whether Illinois EPA NPDES coverage is also required.
Not seeing your county office or county?
Not every county office publishes its rules online. Try these, in order:
- General Start with the statewide information above.
- Closest verified Nearest places where we have verified local data outside this state (distance from Illinois's population center, for comparison only):
- Fountain County Health Department — Septic Systems, Indiana · about 100 miles
- Jackson County Environmental Health - Onsite Wastewater Treatment, Iowa · about 132 miles
- Wisconsin DSPS - POWTS Program, Wisconsin · about 136 miles
- Call to confirm Ask the official office.Illinois EPA — Illinois Surface Discharge Permit (ILG62)
Website →Phone: (217) 782-3397 (as listed on that page, checked Oct 4, 2026)Your city or county office: Local governments →Not sure who handles it locally? USAGov's free help line, 1-844-872-4681, or the Illinois page on USA.gov can point you to the right office. - Know the current info? Tell us with a link to the official page.