Building permits, zoning and septic rules in DuPage County, Illinois

Unincorporated DuPage County requires building permits for new houses and listed residential accessory projects under its adopted building code¹. The county directs applicants to an online process for new houses and residential accessory work such as decks, detached garages, fences, sheds and pools¹. No work may begin before permit issuance, and inspections require at least 24 hours of advance notice through the Building Division at 630-407-6700¹³. Tearing off roofing or siding triggers a roofing or siding permit¹³. Before anyone uses, furnishes or occupies the completed building, DuPage County requires a final inspection and a certificate of use and occupancy⁶. Illinois lets qualifying owner-occupants perform plumbing on their single-family residence, but that narrow rule is not a general exemption from DuPage County building permits or other trade requirements^10,14.

The DuPage County Building & Zoning Department handles building permits for unincorporated land; its contact details and online application link appear above¹. County applications use Accela Citizen Access, with owner authorization, trust disclosure, drainage-easement and other forms potentially required depending on the project¹⁵. Work on properties using wells or septic may also need Health Department review or a health permit¹⁵. The county's rules apply to unincorporated land. Inside Naperville¹⁶, Elmhurst¹⁷, Lombard¹⁸, Hanover Park¹⁹, Addison²⁰, Woodridge²¹ and Glendale Heights²², the city or village issues building permits. Septic and private-well permitting for addresses in DuPage County stays with the DuPage County Health Department^4,5.

DuPage County administers zoning on unincorporated lots; the zoning portal and County Zoning Division can help identify the parcel's designation^7,8. Inside Naperville²³, Wheaton²⁴, Downers Grove²⁵, Lombard²⁶, Bartlett²⁷, Hanover Park²⁸, Addison²⁹, Woodridge³⁰, Glendale Heights³¹ and Glen Ellyn³², the municipality sets zoning, not the county. DuPage County Health Department still handles septic and private-well permits for DuPage County addresses^4,5. The county's guides identify R-1 through R-4 as single-family districts and R-5 through R-7 as multifamily; call the Zoning Section at 630-407-6700 for multifamily construction⁸. In unincorporated R-1, a detached dwelling generally needs a 100,000-square-foot lot at least 165 feet wide and 200 feet deep, with separate treatment for historic lots of record and planned developments³³. R-1 requires a 40-foot front yard, 20-foot side yard and 50-foot rear yard; detached houses on lots smaller than 40,000 square feet may not exceed 36 feet in height¹¹. The Zoning & Planning Division handles variations, conditional uses and rezoning³⁴.

The DuPage County Health Department runs the private sewage disposal program for the whole county, city or village addresses included, and sends applicants to Plan Review at 630-221-7045 for a permit to install a new septic system or repair an existing one⁴. Installing or repairing a private well uses the same Plan Review contact⁵. Fees are adjusted annually for inflation; the schedule effective December 1, 2025 lists $684 for a new septic system permit and plan review, $344 for a renovation or repair permit, $376 for a new well application, and $1,059 for a combined new well-and-septic application⁹. Health Department permit-system users must create an account³⁵. Surface-discharge aerobic systems require an operating permit and annual inspection and may be regulated by the county or Illinois Environmental Protection Agency³⁶. Only about 0.2% of DuPage County soils avoid severe limits for conventional drain fields, so obtain a site evaluation before assuming a standard system will work¹².

We could not confirm a DuPage County rule allowing long-term RV occupancy or a tiny home as a standalone residence on a private unincorporated parcel⁸. The county publishes district-specific zoning materials, and some temporary uses require review and approval with conditions on location, parking and duration, but that does not establish permission to live in an RV¹¹. Illinois rules for licensed manufactured-home communities and commercial campgrounds do not answer the private-lot question^37,38. Give the Zoning & Planning Division the parcel number, proposed unit and intended duration before buying or moving a unit onto the land³⁴.

1. Confirm that the parcel is in unincorporated DuPage County, because a city or village uses its own building-permit and zoning authority².
2. Identify the zoning district and confirm lot size, setbacks, height and any needed zoning relief with the Zoning & Planning Division^11,33,34.
3. If public utilities are unavailable, apply through Health Department Plan Review (630-221-7045) for private-well and septic permits before finalizing the house location^4,5.
4. Submit the building application in Accela Citizen Access with the project-specific forms and any required Health Department review¹⁵.
5. Complete required inspections and obtain the certificate of use and occupancy before moving in or furnishing the building⁶.

For unincorporated property on DuPage County sanitary sewer, new structures, tear-downs and additions over 800 square feet require new service lines to the main sewer; contact Public Works at 630-407-6800 before budgeting the work¹⁵. For private systems, assess septic soils and obtain well and septic permits through the Health Department^4,5,12. Development in an unincorporated regulatory floodplain requires an Elevation Certificate; temporary structures on properties with floodplain, wetlands or wetland buffers may need additional approvals^8,39. A driveway touching an Interstate, U.S. or Illinois route needs a separate state access permit⁴⁰. DuPage County's effective property tax rate is about 2.1%, with a median annual bill near $7,833¹².