Zoning, building permits and septic rules in Wilmington, Illinois

Wilmington’s own rules

• Building permitRequired

  Construction work inside Wilmington city limits; the city building department administers permits.

  • The city page lists some work that does not need a permit (landscaping, exterior and interior painting, repair or replacement of fixed appliances).
  • Building permit placard must be displayed from the street.

  “obtain a building permit (if you are unsure if a permit is required, please call the city hall and ask for the building department).”

• InspectionsRequired

  Permitted construction inside Wilmington city limits

  • Inspections are scheduled through constructioncodes.com/inspections, per the city page.
  • The city contracted B&F Construction Code Services, Inc. for reviews and inspections.

  “schedule inspections as necessary: don't proceed with additional work until completed work has been inspected.”

• Local zoningPresent

  Land inside Wilmington city limits (Wilmington, IL 60481, Will/Grundy county area); the city's own zoning ordinance, Chapter 150 of its code, governs.

  • Zoning chapter is Ord. 1324 (passed 1-4-00) as amended, per the Municode text.
  • Official zoning map is the 2026 Wilmington Zoning Map published by the city.

  “all the land in the city is divided into the following districts: a-1 agricultural district e-r estate residential district”

• Zoning districtsPublished

  Land inside Wilmington city limits

  • Districts: A-1, E-R, G-R, R-1, R-2, R-3, R-4, R-5, R-B, B-1, B-2, B-2A, B-3, I-1, I-2, I-3 per the city zoning page and Chapter 150.

  “r-b restricted business district b-1 neighborhood commercial district b-2 light commercial district b-2a central business district b-3 general commercial district i-1 office, research and light industrial district i-2 light industrial district i-3 heavy industrial district”

• Minimum lot sizeSpecified

  Single-family detached dwelling in the E-R estate residential district inside Wilmington city limits

  • Nonresidential uses require five acres unless otherwise specified.
  • Minimum lot width 100 feet for single-family detached dwellings in E-R.

  minimum lot size: >= 20000 square feet (nonresidential uses five acres, unless otherwise specified)

  “the minimum lot size for permitted and conditional land uses in the e-r estate residential district shall be as follows: expand single-family detached dwelling 20,000 square feet nonresidential uses five acres, unless otherwise specified”

  2 more reviewed findings on this topic

  • Specified — Single-family detached dwelling in the R-1 single-family residential district inside Wilmington city limits

    “the minimum lot size for permitted and conditional land uses in the r-1 single-family residential district shall be as follows: expand single-family detached dwelling 10,000 square feet nonresidential uses five acres, unless otherwise specified”

  • Specified — Single-family dwelling in the A-1 agricultural district inside Wilmington city limits

    “(10) single-family dwelling, only if ancillary and lot size is not less than 10 acres.”

• SetbacksSpecified

  Principal building in the E-R estate residential district inside Wilmington city limits

  • Side yard 15 feet and rear yard 25 feet from the lot lines, per the same section.

  front yard setback: 40 feet

  “(a) front yard. no principal building shall be allowed within 40 feet of any front lot line or a street right-of-way line. (b) side yard. no principal building shall be allowed within 15 feet of any side lot line. (c) rear yard. no principal building shall be allowed within 25 feet of any rear lot line.”

  One more reviewed finding on this topic

  • Specified — Principal building in the R-1 single-family residential district inside Wilmington city limits

    “(a) front yard. no principal building shall be allowed within 30 feet of any front lot line or a street right-of-way line. (b) side yard. no principal building shall be allowed within 10 feet of any side lot line. (c) rear yard. no principal building shall be allowed within 25 feet of any rear lot line.”

• Lot coverageSpecified

  Commercial uses in the B-2 light commercial district inside Wilmington city limits

  • Municode section 150.60 applies to the B-2 district.

  maximum site coverage: <= 70 percent

  “(4) maximum site coverage. site coverage shall not exceed 70%.”

  One more reviewed finding on this topic

  • Specified — Non-residential uses in the R-B restricted business district inside Wilmington city limits

    “(5) maximum site coverage. site coverage shall not exceed 40%.”

• Building heightSpecified

  Buildings in the E-R estate residential district inside Wilmington city limits

  • Same limit as the R-1 and G-R districts in Chapter 150.

  maximum building height: <= 30 feet (two and one-half stories)

  “(4) building height limitation. no building shall exceed two and one-half stories or 30 feet in height.”

  One more reviewed finding on this topic

  • Specified — Buildings in the R-1 single-family residential district inside Wilmington city limits

    “(4) building height limitation. no building shall exceed two and one-half stories or 30 feet in height.”

• Living in an RVLimited

  Storage of recreational vehicles on private lots inside Wilmington city limits; the code does not expressly address living in an RV as a dwelling.

  • RVs may be stored only in the rear yard or within a fully enclosed building or structure, not in required front or corner-side setbacks, except as provided in subsection (b).
  • Parking or storage must not create a dangerous or unsafe condition.
  • Recreational vehicles may be kept on a driveway for up to 45 days of non-usage.
  • Parking on public streets or rights-of-way is unlawful for RVs, boats and trailers.

  “(b) temporary storage and parking of recreational vehicles. recreational vehicles may be placed, kept or maintained upon any driveway without meeting the requirements of this section for a period not exceeding 45 days of non-usage.”

Still unanswered

We looked and could not find an official answer yet. Silence is not permission; ask Wilmington or Will County directly.

• Owner-builder exemption — Owner-builders inside Wilmington city limits
• Building code adopted — Construction inside Wilmington city limits
• Certificate of occupancy — New dwellings inside Wilmington city limits
• Minimum dwelling size — Minimum dwelling floor area inside Wilmington city limits
• Camping on your land — Temporary camping on private land inside Wilmington city limits

Each answer was extracted from an official source and independently re-checked against that source by a second reviewer. That is an evidence check, not legal advice. Rules change; confirm with the authority before you buy or build.