ADU Pass
Clinton
ADU Pass helps homeowners in Clinton, De Witt County, Illinois navigate the permit paperwork for building an accessory dwelling unit. This area covers 3 ZIP codes.
Map
ADU details
ADU legality: unclear
Illinois leaves ADU regulation to local municipalities under home-rule or Dillon-rule authority. Clinton permits ADUs subject to local conditions per its zoning ordinance.
Cost scenarios
| Scenario | Sq ft | Permit | Build | Total |
|---|---|---|---|---|
| minimum | 150 | $2,400 | $41,250 | $43,650 |
| 600 | 600 | $2,400 | $165,000 | $167,400 |
| midpoint | 525 | $2,400 | $144,375 | $146,775 |
| maximum | 900 | $2,400 | $247,500 | $249,900 |
Fee breakdown (as of 2026-04)
Permitting process
- Confirm parcel inside Clinton city limits vs unincorporated DeWitt County (~1d)
Clinton city limits do not include large rural sections of DeWitt County. The City of Clinton Building & Zoning Department handles permits inside city limits; the DeWitt County Planning & Zoning Department (same building, 201 W. Washington Street) handles unincorporated parcels including most of the Clinton Lake shoreline. Verify jurisdiction first because the form package and inspector are different. - Pre-application zoning consultation at City Hall (~5d)
Walk-in consultation with Clinton Building & Zoning at 119 N. Center Street (City Hall) or call 217-935-3432. Staff identify zoning district, accessory-use status, and whether the proposed ADU clears CMC §6.06 building regulations and the underlying zoning chapter. Owner-occupancy and minimum lot size are the routine sticking points. - Submit application through CloudPermit + paper supplements (~1d)
Building permit submitted via the DeWitt County / Clinton CloudPermit portal launched in 2023. Site plan, floor plan, structural sketch, electrical/plumbing scope. For parcels near Clinton Lake, FEMA flood zone determination required. Septic/well documentation routed to DeWitt County Health Department for parcels off city sewer. - Zoning Board of Appeals (if Special Use needed) (~35d)
If the ADU is not a permitted accessory use in the underlying district (most common in older Clinton residential areas where ADUs were not historically contemplated), application is referred to ZBA. Notice published in DeWitt County Republican; abutters notified. - Plan review against IRC 2021 with Illinois amendments (~14d)
Clinton Building Inspector reviews against IRC 2021 with Illinois state amendments (no residential sprinkler mandate per state R313 amendment). Floodplain construction standards apply for SFHA parcels along Salt Creek and Clinton Lake margins. - Pay fees, receive permit (~2d)
Permit fees paid through CloudPermit or in person at 119 N. Center Street. Sewer connection fee paid separately to City of Clinton water/sewer billing. - Inspection cycle
Footing, foundation, rough framing/MEP, insulation, final - scheduled through CloudPermit. Single building inspector covers all of Clinton plus shared county load on rotation. - Certificate of Occupancy / final approval (~5d)
Final inspection sign-off triggers Certificate of Occupancy. ADU eligible for occupancy and rental once water and sewer service confirmed by City billing.
Viability (permitted uses)
- Long-term rental: yes Long-term rental of ADU generally permitted; landlord-tenant law and any city rental-registration ordinance apply.
- Short-term rental: with-restrictions STR rules vary by city. Clinton regulates STRs separately from ADU permitting; check local STR ordinance and HOA covenants.
- Office rental: with-restrictions Detached office rental requires home occupation permit or rezoning.
- Home office: yes Home occupation permitted with restrictions on signage and customer traffic.
- Studio / workshop: yes Personal artist studio is a permitted accessory use.
- Agriculture: with-restrictions Limited urban agriculture permitted in residential zones; livestock varies by district.
- Relative support: yes Family-occupancy ADU explicitly permitted in single-family zones.
Contacts
Staff: City of Clinton Building & Zoning (Permit intake, plan review, inspections (city limits)), DeWitt County Planning & Zoning (Unincorporated parcels, ZBA hearings, comprehensive plan), DeWitt County Health Department (Septic/well permits for parcels off city water-sewer (Clinton Lake area))
Utilities
- Water: Clinton Water Utility · 30d connect · $4,500
- Sewer: Clinton Sewer / Wastewater · 30d connect · $5,500
- Electric: Clinton Electric Utility · 21d connect · $1,800
- Gas: Clinton Gas Utility · 30d connect · $1,500
Property values & taxes
Construction timeline
Realistic total: best 7mo · typical 10mo · worst 16mo
Financing
State ADU loans:
Insurance impact
HOA prevalence & preemption
Illinois has no HOA-ADU preemption; HOA covenants restricting ADUs are enforceable.
Technical envelope (climate & building code)
Climate & energy code
Building code
Amendments:
- Amendment
- Amendment
Legal history (timeline)
Current ordinance: Clinton Municipal Code Chapter 6.06 (Building Regulations) and zoning chapter, adopted 2008-01-01, last amended 2023-06-01
- 1972-08-08 — DeWitt County Zoning Regulations adopted by County Board (county-ordinance)
DeWitt County established countywide zoning regulations to promote public health, safety, comfort, and general welfare. The county code defines permitted uses, lot-size minimums, and setbacks for each zoning district.
Effect: Established the dual-jurisdiction posture in DeWitt: Clinton operates its own Building & Zoning Department under Clinton Municipal Code, while unincorporated parcels around Clinton fall under the County's 201 W. Washington Street office (sharing the same building as City Hall). - 1979-09-30 — Clinton Power Station first commercial operation - regional economic baseline (city-ordinance)
Clinton's nuclear-driven employment base (Constellation Energy operates the single-unit BWR; Clinton Lake serves as cooling reservoir) established the higher-than-typical-rural housing tenure that supports ADU demand for plant-staff temporary housing.
Effect: Underpins Clinton's relatively active accessory-housing market; multigenerational and rented-room arrangements have been historically common around the plant's operating workforce. - 2023-06-01 — City of Clinton CloudPermit online intake adoption (DeWitt County aligned) (city-ordinance)
DeWitt County moved building-permit submittal to the CloudPermit online platform; the City of Clinton followed on the same system to align workflows with the county-shared 201 W. Washington address.
Effect: Replaced the pure paper-counter intake with a hybrid CloudPermit + counter pathway; ADU applications can now be submitted digitally through the same portal used by the county for unincorporated parcels. - 2024-02-15 — Illinois HB 4439 (statewide ADU enabling) introduced (state-law)
HB 4439 would mandate by-right ADUs statewide. As of the 103rd General Assembly the bill remained in committee.
Effect: If enacted, would constrain Clinton's discretionary special-use route for ADUs and force ministerial review on owner-occupied lots. Until then, Clinton Municipal Code §6.06 (Building) and the underlying zoning chapter control.
Illinois state — ADU law and programs
State financing programs
Illinois does not operate an ADU-specific statewide loan, grant, or forgivable-loan program. The Illinois Housing Development Authority (IHDA) is the state's housing finance agency and administers a robust portfolio of homebuyer products: Access Forgivable, Access Deferred, Access Repayable down-payment-assistance variants, the IHDA Mortgage first-mortgage product, and the federal Low-Income Housing Tax Credit allocation. The 2025 IHDA Access Home program offers DPA equal to 6% of purchase price up to $15,000. None target ADU construction directly; an ADU-bearing primary residence on an Illinois lot can qualify for the underlying mortgage when other criteria are met.
Federal (United States) — ADU-relevant rules and programs
Federal ADU law
The United States has no federal statute that directly regulates accessory dwelling unit entitlement or design. Land-use authority over ADUs resides with states and local governments under the traditional police power. Federal engagement is limited to financing (Fannie/Freddie/FHA/VA/USDA), flood insurance (FEMA/NFIP), and discretionary housing programs (HUD), which are recorded in sibling sections of this file.
Federal financing programs
Federal housing-finance agencies and GSEs set nationwide underwriting rules that govern whether an ADU can be financed, appraised, and counted toward mortgage qualifying income. The relevant actors are Fannie Mae, Freddie Mac, FHA (HUD), VA, and USDA Rural Development.
Federal tax credits
There is no ADU-specific federal tax credit. ADUs may incidentally qualify for existing federal energy-efficiency and clean-energy tax credits when the ADU construction includes qualifying measures.
Federal housing programs
HUD administers several discretionary programs that can fund ADU-related activity at the grantee's election, but none is an ADU-specific program.
ZIP Codes
- 61727
- 61749
- 61750
Post Office
- 105 N Quincy St, 61727