Zoning, building permits and septic rules in Duncan Township, Illinois

Duncan Township’s own rules

• Building permitRequired

  Buildings and structures in the unincorporated portion of Duncan Township.

  • Routine maintenance or repair, alterations costing less than $1,000 that do not change exterior enclosed dimensions, construction of a service connection to a municipally owned utility, and agricultural uses are listed as exceptions to permits or certificates.
  • The required authorization is a Zoning Certificate from the Mercer County Zoning Officer.

  “No building or structure shall be constructed, reconstructed, erected, moved in, or altered within the unincorporated portions of Mercer County without first obtaining a Zoning Certificate from the Zoning Officer which indicates that the proposed building or structure complies with all the provisions of this Resolution.”

• Certificate of occupancyRequired

  A building or addition constructed after the effective date of the Mercer County resolution, and land first put to nonagricultural use, in unincorporated Duncan Township.

  • A change from one permitted use to another permitted use is excepted from the stated change-in-use certificate condition.
  • The certificate must state that use or occupancy complies with the resolution.

  “after the effective date of this Resolution shall be occupied, and no land not in use on the effective date of this Resolution shall be used for any non-agricultural purpose until a Certificate of Occupancy has been issued by the Zoning Officer. No change in use, other than that of a permitted use to another permitted use, shall be made until a Certificate of Occupancy has been issued by the Zoning Officer. Every Certificate of Occupancy shall state that the use of occupancy complies with the provisions of this Resolution.”

• Local zoningPresent (with conditions)

  Land in Duncan Township that is in the unincorporated area of Mercer County; zoning is administered by Mercer County, not shown by this source to be a Duncan Township ordinance.

  • The cited resolution expressly applies to the unincorporated area of Mercer County; incorporated areas are outside its stated scope.

  “This Resolution shall divide the unincorporated area of Mercer County into districts, regulate therein the use of land, buildings, and structures; regulate the location, erection, construction, reconstruction, and alteration of such buildings and structures; regulate the height, number of stories, and size of all buildings and other structures ; and regulate the density of population.”

• Zoning districtsPublished (with conditions)

  Unincorporated land in Duncan Township subject to the Mercer County zoning resolution.

  • The official zoning maps are filed in the Mercer County Board Room and are open to public reference during office hours.
  • This source does not establish a Duncan Township-administered zoning district system.

  “shall be as much a part of this Resolution as though fully set forth and described herein. The said maps shall be filed in the Mercer County Board Room, and shall be open to public reference at all times during which that office is open.”

• Minimum dwelling sizeDistrict specific (with conditions)

  Dwellings in the unincorporated portion of Duncan Township, subject to the applicable Mercer County zoning district.

  • The opened resolution establishes district-based regulation of building size; this research did not extract a residential district schedule or a numeric dwelling-area minimum.

  “This Resolution shall divide the unincorporated area of Mercer County into districts, regulate therein the use of land, buildings, and structures; regulate the location, erection, construction, reconstruction, and alteration of such buildings and structures; regulate the height, number of stories, and size of all buildings and other structures ; and regulate the density of population.”

• Minimum lot sizeDistrict specific (with conditions)

  Lots in the unincorporated portion of Duncan Township, subject to the applicable Mercer County zoning district.

  • The opened resolution establishes district-based land regulation; this research did not extract a district lot-area table or numeric standard.

  “This Resolution shall divide the unincorporated area of Mercer County into districts, regulate therein the use of land, buildings, and structures; regulate the location, erection, construction, reconstruction, and alteration of such buildings and structures; regulate the height, number of stories, and size of all buildings and other structures ; and regulate the density of population.”

• Building heightDistrict specific (with conditions)

  Buildings in the unincorporated portion of Duncan Township, subject to the applicable Mercer County zoning district.

  • The zoning resolution provides district-based regulation of building height; numeric height limits were not extracted in this pass.

  “This Resolution shall divide the unincorporated area of Mercer County into districts, regulate therein the use of land, buildings, and structures; regulate the location, erection, construction, reconstruction, and alteration of such buildings and structures; regulate the height, number of stories, and size of all buildings and other structures ; and regulate the density of population.”

• Agricultural exemptionAvailable (with conditions)

  Agricultural uses in the unincorporated portion of Duncan Township.

  • Agricultural buildings and land uses remain subject to federal, state, and local floodplain regulations.
  • Agricultural structures must comply with the minimum setback requirements stated in the resolution.

  “Illinois Revised Statutes, Chapter 34, Section 3151 provides that permits with respect to the erection, maintenance, repair, alteration, remodeling or extension of buildings or structures used or to be used for agricultural purposes shall be issued free of charge. It further provides that the powers of the Act shall not be exercised so as to impose regulations or require permits with respect to land used or to be used for agricultural purposes, or with respect to the erection, maintenance, repair, alteration, remodeling or extension of buildings of structures used or to be used for agricultural purposes upon such land except that such buildings or structures for agricultural purposes may be required to conform to building or set back lines.”

Rules another office applies inside Duncan Township

Duncan Township does not set these itself; the county, a health district or the state does, and they apply to every address inside its limits.

• Who permits septicLocal (with conditions)

  Private well and septic systems serving residents in Duncan Township, Mercer County.

  • The health department identifies well/septic inspection and permitting as part of its program; site-specific approval conditions were not published on the opened webpage.

  “Lead Poisoning Prevention, Food & Tanning Education/Inspection, Well/Septic Inspections and Permitting, and Vector Surveillance”

• Septic permitRequired

  Onsite septic systems in Duncan Township served by the Mercer County Health Department.

  • The department’s environmental-health forms page directs applicants to print applicable forms and mail or deliver completed forms to the department.

  “permit application to construct or repair”

Still unanswered

We looked and could not find an official answer yet. Silence is not permission; ask Duncan Township or Mercer County directly.

• Owner-builder exemption — Owner-built residential construction inside Duncan Township.
• Building code adopted — Construction inside Duncan Township.
• Inspections — Building construction inside Duncan Township.
• Lot coverage — Lots in Duncan Township.
• Living in an RV — Long-term RV occupancy on private land in Duncan Township.

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.