Zoning, building permits and septic rules in Rock Island, Illinois

Rock Island’s own rules

• Building code adoptedAdopted

  New construction, alterations and repairs of buildings inside Rock Island city limits, under the 2021 International Building, Residential and Existing Building Codes as amended by the city.

  • Plumbing is governed by the Illinois Plumbing Code: 'the most recent edition of the illinois plumbing code shall apply to the installation, alteration, repair, relocation, addition, replacement, and maintenance of plumbing systems'.
  • Amendments to the 2021 IBC, IRC and IEBC are listed in the city appendix; the city's 2025 amendments were the version checked.

  “this appendix contains the adopted amendments to the 2021 international building code (ibc) international residential code (irc) international existing building code (iebc) as applied by the city of rock island.”

• Local zoningPresent (with conditions)

  Land inside Rock Island city limits. The City of Rock Island adopts and administers its own zoning code (2020 Zoning Code for the City of Rock Island).

  • The 2020 code PDF is the version checked; later amendments were not confirmed.
  • Permitted uses and dimensions depend on the zoning district.

  “2020 zoning code for the city of rock island”

• Zoning districtsPublished

  Zoning district regulations in the City of Rock Island 2020 Zoning Code (R-1, R-2 and R-3 chapters were seen in the PDF)

  • Only the R-1 chapter's general description was quoted; the R-2 and R-3 chapters are also in the 2020 PDF but were not quoted.

  “1. general description. the purpose of the r-2 one and two unit residential district is established to provide housing opportunities that can also establish duplexes on a single lot in an urban setting at a low to medium density level.”

• Minimum dwelling sizeSpecified

  Principal dwellings inside Rock Island city limits (general provisions of the zoning code, applies to all districts where dwellings are permitted)

  • Dwellings must also meet the standards of the international building code.

  minimum floor area of principal dwelling: > 400 sq ft (must also meet the standards of the international building code)

  “the floor area of a principal dwelling shall exceed four hundred (400) square feet and meet the standards of the international building code.”

• Minimum lot sizeSpecified

  R-1 One Unit Residential district lots inside Rock Island city limits (lot width only; lot area not legible in the PDF table)

  • The PDF table for R-1 has the column headings lot width, front yard depth, side yard width and rear yard depth; a lot-area column is not legible in the extracted text, so the R-1 minimum lot area is not confirmed here.
  • Lots unserved by sewer and water follow a separate rule (see the second minimum_lot_size claim).

  minimum lot width: >= 50 ft (applies to 1 to 1 1/2 story and 2 to 2 1/2 story dwellings)

  “6. lot area, frontage, and yard requirements: the following minimum requirements shall be observed. number of stories lot width front yard depth side yard width rear yard depth 1 to1½ 50 ft. 25 ft. 6 ft. 30 ft. 2 to 2½ 50 ft. 25 ft. 8 ft. 30 ft.”

  One more reviewed finding on this topic

  • Specified — Lots in any zoning district where neither public water supply nor public sanitary sewer is accessible, inside Rock Island city limits

    “3. lots unserved by sewer and water. in any district where neither public water supply nor public sanitary sewer is accessible, the otherwise specified lot area and width requirement shall be twenty thousand (20,000) square feet and one hundred (100) feet; respectively, provided, however, that where a public water supply system is accessible and will be installed, these requirements shall be ten thousand (10,000) square feet and seventy-five (75) feet respectively, provided further that the health officer has certified”

• SetbacksSpecified

  R-1 One Unit Residential district lots inside Rock Island city limits

  • Side yard is 6 ft for 1 to 1 1/2 story dwellings and 8 ft for 2 to 2 1/2 story dwellings.
  • Front yard, side yard and rear yard figures are minimums from the R-1 table; yard projections and exceptions in the general provisions also apply and were not fully reviewed.

  front yard depth: >= 25 ft (all story groups listed in the R-1 table) · side yard width: >= 6 ft (1 to 1 1/2 story dwellings; 8 ft for 2 to 2 1/2 story) · rear yard depth: >= 30 ft (all story groups listed in the R-1 table)

  “1 to1½ 50 ft. 25 ft. 6 ft. 30 ft. 2 to 2½ 50 ft. 25 ft. 8 ft. 30 ft.”

• Building heightSpecified

  R-1 One Unit Residential district principal and accessory structures inside Rock Island city limits

  • Accessory structures are limited to one story.

  principal structure height: <= 35 ft (also limited to 2 1/2 stories)

  “no principal structure shall exceed 2 ½ stories or thirty-five feet (35') in height. no accessory structure shall exceed one (1) story.”

• Short-term rentalsLimited

  Short-term rentals as a permitted principal use in the R-1 One Unit Residential district inside Rock Island city limits

  • Must make available a minimum of one off-street parking spot for the occupant of each short-term rental unit at the property.
  • Operator must reside within the city of Rock Island or within ten miles of its periphery.
  • No signage exceeding one square foot in area.

  off-street parking spaces per short-term rental unit: >= 1 spaces

  “j. short-term rentals which must make available a minimum of one off-street parking spot for use by the occupant of each short-term rental unit at the property, the operator shall reside within the city of rock island or within ten (10) miles of its periphery and shall not have signage exceeding one (1) square foot in area.”

Still unanswered

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

• Building permit — Building permits for construction inside Rock Island city limits
• Owner-builder exemption — Owner-builder construction inside Rock Island city limits
• Inspections — Building inspections inside Rock Island city limits
• Certificate of occupancy — Certificates of occupancy inside Rock Island city limits
• Lot coverage — Lot coverage for dwellings inside Rock Island 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.