Zoning, building permits and septic rules in South Ottawa Township, Illinois

Rules another office applies inside South Ottawa Township

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

• Building permitRequired

  Commercial projects and residential structures on unincorporated land inside South Ottawa township

  • Permits are required for residential structures 200 square feet or larger, or with any side 20 feet or greater, and for residential remodeling with structural changes, signs, fences, pools, solar and wind equipment, and towers.
  • Construction beginning before the building permit is issued is subject to a penalty of double the permit fee, with each day a separate offense.
  • Permit applications must include construction documents, a site diagram, a copy of the approved well permit and a copy of the approved septic permit from the LaSalle County Health Department.
  • Other county ordinances (subdivision, floodplain, mobile home park, setback and zoning) must be met before issuance; a permit is denied if one is violated.
  • Structures inside a city or village boundary do not need a county permit, and structures under 200 square feet with no side over 20 feet do not need one.

  minimum structure size requiring permit: >= 200 square feet (or any side 20 feet or greater)

  “building permits are required for all commercial projects, all residential structures over 200 square feet or larger than 20 feet on any side”

• Building code adoptedAdopted (with conditions)

  New residential and commercial construction requiring a county building permit on unincorporated land inside South Ottawa township

  • Residential: International Residential Code 2024 and National Electrical Code 2023 as amended by the LaSalle County Board, per the county brochure.
  • Non-agricultural commercial and multi-family: International Building Code 2024, IFC 2024, IMC 2024, IFGC 2024, IEBC 2024, IECC 2024 and NEC 2023 as amended by the county board.
  • Agricultural buildings used for bona fide agriculture are exempt from county building code inspections and fees (see agricultural_exemption claim).

  “residential structures that require building permits are subject to the international residential codes”

• InspectionsRequired

  Structures receiving a county building permit on unincorporated land inside South Ottawa township

  • Agricultural bona fide structures are exempt from county building code inspections.
  • Inspections must be scheduled with at least 48 hours allowed for scheduling.

  “building code inspections will apply to all structures which receive building permits.”

• Certificate of occupancyRequired

  Occupancy of new structures on unincorporated land inside South Ottawa township

  • Occupancy permit is issued by the building code inspectors after a passing final inspection.
  • The owner must certify that the LaSalle County Health Department has approved the well and septic before an occupancy permit is issued.

  “occupancy and use of a structure (which includes but is not limited to moving furniture and personal items into the structure) is forbidden without an occupancy permit.”

• Zoning districtsPublished (with conditions)

  Unincorporated land inside South Ottawa township, where the LaSalle County Zoning Ordinance applies because no township zoning ordinance was located in this research

  • Applies only to unincorporated land; incorporated municipalities such as the City of Ottawa are governed by their own codes.
  • District boundaries are shown on the zoning district map of each township, adopted by reference (sec. 6.1).

  “the provisions of this ordinance shall apply to all properties in unincorporated lasalle county as hereinafter specifically provided”

• Minimum lot sizeSpecified

  R-2 single family residence district on unincorporated land inside South Ottawa township, single-family detached dwelling

  • Applies where public sanitary sewer and water are available; otherwise the 1 acre rule applies (see parameter exception).

  minimum zoning lot area, single-family detached, public sewer and water: >= 10000 square feet (served by public sanitary sewer and water) · minimum zoning lot area, single-family detached, private sewer or water: >= 1 acre (served by private sanitary or private water systems)

  “single family detached dwellings: the zoning lot shall be not less than ten thousand (10,000) square feet in size for properties that are served by public sanitary sewer and water and the zoning lot shall not be less than one (1) acre in size for properties served by private sanitary or private water systems.”

  2 more reviewed findings on this topic

  • Specified — A-1 agriculture district on unincorporated land inside South Ottawa township, single-family detached dwelling

    “single family detached dwellings: the zoning lot shall be not less than thirty-five (35) acres.”

  • Specified — R-1 rural residence district on unincorporated land inside South Ottawa township, single-family detached dwelling

    “1. single family detached dwellings: the zoning lot shall not be less than one (1) acre in size.”

• SetbacksSpecified

  Building setbacks in most zoning districts on unincorporated land inside South Ottawa township

  • The Land Use page says the setbacks apply in most zoning districts; the brochure setback table gives per-district values and notes variation by use and adjacent district, which was not fully transcribed.

  front setback from township road centerline: 70 feet (most zoning districts) · front setback from county road centerline: 85 feet (most zoning districts) · front setback from state or federal route centerline: 100 feet (most zoning districts) · side and rear setback: 10 feet (most zoning districts)

  “building setbacks in most zoning districts are 70 feet from township road centerline, 85 feet from county road centerline, 100 feet from state/federal route centerline, and 10 feet from side/rear yards.”

• Building heightSpecified

  A-1 agriculture district dwellings on unincorporated land inside South Ottawa township

  • On zoning lots of one acre or greater, non-dwelling buildings have no height limit; on lots under one acre, non-dwelling buildings are capped at 36 feet.

  maximum height, dwelling units: <= 36 feet (A-1 district)

  “on all buildings used as dwelling units the building height shall not exceed thirty-six (36) feet in height.”

  One more reviewed finding on this topic

  • Specified — R-1 rural residence district single-family detached dwellings on unincorporated land inside South Ottawa township

    “single family detached dwellings shall not exceed thirty-six (36) feet in height.”

• Living in an RVLimited

  Living or sleeping in a recreational vehicle on unincorporated land inside South Ottawa township

  • Not allowed in a subdivision, an unincorporated platted town, or on a parcel with an existing residence, unless otherwise permitted by the ordinance.

  maximum RV living or sleeping period: <= 180 days per calendar year (not in subdivisions or on parcels with an existing residence)

  “a recreational vehicle, as defined in chapter 3, may be used for living or sleeping purposes for a period not exceeding 180 days in a calendar year.”

• Manufactured homesLimited

  Manufactured homes in the R-1 rural residence district on unincorporated land inside South Ottawa township

  • Listed as a special use in the R-1 district; needs a special use permit under the county procedures.

  “mobile homes and manufactured homes with a permanent foundation (see chapter 3 definitions). if less than 1000 square feet in size and/or greater than 10 years old).”

• Accessory dwellingsLimited

  Accessory dwelling units in the R-1 rural residence district on unincorporated land inside South Ottawa township

  • Listed among the R-1 uses; the opened excerpt does not make clear whether it is a permitted or special use, so confirm the permitted use list in sec. 8.1-3 and 8.1-4.
  • R-2 and R-3 also list an accessory dwelling unit.

  “only one accessory dwelling unit is allowed per lot or parcel.”

• Who permits septicCounty (with conditions)

  Private sewage disposal systems on land inside South Ottawa township, administered by the LaSalle County Health Department

  • Governed by the Illinois Private Sewage Disposal Licensing Act and Code, with the county health department as the permitting body.

  “will not be issued until a completed application and fee have been submitted to the lasalle county health department and an onsite survey performed by department personnel.”

• Septic permitRequired

  Installing or repairing a private sewage disposal system on land inside South Ottawa township

  • Application requires a plat of survey, a plot plan, and a soil investigation report.
  • Permit is not issued until a completed application and fee are submitted and an onsite survey is performed by department personnel.
  • Fee is paid through the Health Department online portal under Septic Permit/Training.

  “will not be issued until a completed application and fee have been submitted to the lasalle county health department and an onsite survey performed by department personnel.”

• Septic inspectionRequired

  Private sewage disposal systems installed on land inside South Ottawa township

  • The health department must be notified before backfilling for final inspection.
  • The county building inspector will not issue an occupancy permit until the health department's well and septic approval is certified, which takes at least 48 hours.

  “the health department must be notified for a final inspection sewage disposal system construction before backfilling.”

• Well permitRequired

  Constructing, modifying or sealing a water well on land inside South Ottawa township

  • A copy of the approved well permit from the LaSalle County Health Department must be attached to the building permit application.

  “it shall be unlawful for any person to construct, modify, and/or seal any water well within the county unless he holds a valid permit issued by the health department.”

• Agricultural exemptionAvailable (with conditions)

  Bona fide agricultural buildings on unincorporated land inside South Ottawa township

  • Requires gross agricultural income of at least 5000 dollars from an agricultural operation, shown by prior-year documentation, and a sworn affidavit.
  • The exemption covers county building code inspections and building code fees; a 25 dollar agriculture exempt fee applies and setbacks and other rules still apply.

  minimum gross agricultural income: >= 5000 USD (bona fide agriculture operation)

  “if these structures are declared bona fide agriculture structures and will be used for agricultural purposes they are exempt from county building code inspections and building code fees.”

• Subdividing landRegulated (with conditions)

  Dividing land into lots on unincorporated land inside South Ottawa township

  • Contact the Land Use Department before subdividing to confirm compliance with the county subdivision ordinance, the zoning ordinance and the Illinois Plat Act.
  • Lots created by division must each meet the bulk regulations of their zoning district; corner lots must be 25 feet wider than the district minimum.

  “please contact our department prior to subdividing property in order to verify that the split will comply with the lasalle county subdivision, lasalle county zoning ordinance, and the illinois plat act.”

• Permit feesPublished (with conditions)

  Building permit fees on unincorporated land inside South Ottawa township

  • Fees are based on square footage and number of inspections; the price is set once plans are reviewed and is nonrefundable.
  • A separate 2025 fee schedule PDF is linked from the Land Use page but was not opened.

  fee schedule location: county building permit ordinance article 6

  “the fee schedule can be found in the lasalle county building permit ordinance”

• Permit processPublished (with conditions)

  Building permit application process on unincorporated land inside South Ottawa township

  • Plans are reviewed by a building inspector, who then notifies the applicant the permit is ready and states the cost; fees are paid by check to the LaSalle County Treasurer when the permit is picked up.
  • Permit inspections require 48 hours to schedule; the Land Use Department is at 119 West Madison Street, Room 107, Ottawa.

  advance application time: >= 30 days

  “apply for a permit at least 30 days in advance of anticipated building.”

Still unanswered

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

• Owner-builder exemption — Owner-builder permit exemption for a home inside South Ottawa township
• Local zoning — Whether South Ottawa township adopts and administers its own zoning ordinance
• Minimum dwelling size — Minimum dwelling floor area on unincorporated land inside South Ottawa township
• Lot coverage — Lot coverage limits on unincorporated land inside South Ottawa township
• Tiny homes — Occupancy of a tiny home inside South Ottawa 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.