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

Rules another office applies inside Waltham Township

Waltham 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

  Residential structures in unincorporated LaSalle County, including Waltham township

  • Building permits are required for all commercial projects and for all residential structures over 200 square feet or larger than 20 feet on any side.
  • Residential remodeling that requires structural changes, signs, fences, pools, solar and wind equipment, and towers is also listed as needing permits.
  • Additional zoning approvals may be necessary depending on the type of project.

  residential structure size threshold: > 200 square feet (or larger than 20 feet on any side)

  “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)

  Residential and commercial construction in unincorporated LaSalle County, including Waltham township

  • Codes are adopted with county amendments; the county says the amendments include a wind load of 105 mph and deletion of energy-efficiency and sprinkler provisions from IRC 2024.
  • Codes listed on the page: International Residential Code 2024, International Building Code 2024, International Fire Code 2024, International Mechanical Code 2024, International Fuel Gas Code 2024, National Electrical Code 2023.

  “effective january 1, 2025; lasalle county building codes will be updated to the following code years with amendments: international residential code 2024”

• InspectionsRequired

  Permitted building work in unincorporated LaSalle County, including Waltham township; inspections are run by the county's contractor SafeBuilt

  • Inspections are scheduled through SafeBuilt by phone or email.
  • The page says all inspections are currently done through a remote video inspection process.

  “to schedule a building inspection: phone: 847-510-4104 email: [email protected] currently, all inspections will be done through a remote video inspection process”

• Local zoningPresent (with conditions)

  Zoning for land inside Waltham township (unincorporated LaSalle County) is the LaSalle County zoning ordinance. No Waltham township zoning ordinance was located; the county's own pages list Waltham Township officials only.

  • The county ordinance applies to all properties in unincorporated LaSalle County.
  • Whether Waltham township has ever adopted its own zoning was not confirmed on a township page; the township officials page does not mention zoning.

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

• Zoning districtsPublished (with conditions)

  Zoning district list for unincorporated LaSalle County, including Waltham township

  • The ordinance divides the unincorporated county into the agriculture, residence, business and industrial districts listed in sec. 6.0.
  • The official zoning district map of each township is adopted by reference; the township map itself was not opened.

  “in order to carry out the purpose and intent of this ordinance, the unincorporated area of the county is hereby divided into the following districts”

• Minimum lot sizeSpecified

  Single-family detached home in the R-2 single family residence district in unincorporated LaSalle County, including Waltham township if zoned R-2 (main single-family residential district)

  • Lots served by public sanitary sewer and water need at least 10,000 square feet.
  • Lots served by private sanitary or private water systems need at least one acre.
  • Lot width is at least 75 feet with public sewer and water, and at least 150 feet with private sewer or water.

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

  “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 — Single-family detached home in the A-1 agriculture district in unincorporated LaSalle County, including Waltham township if zoned A-1

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

  • Specified — Single-family detached home in the rural residence district in unincorporated LaSalle County, including Waltham township if zoned rural residence. Sec. 6.0 calls it R-1; the sec. 8.1 heading reads RR.

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

• SetbacksSpecified

  Building setbacks in most zoning districts of unincorporated LaSalle County, including Waltham township if zoned

  • Front setbacks are measured from road centerlines: 70 ft from township roads, 85 ft from county roads, 100 ft from state or federal routes.
  • Side and rear setbacks are 10 ft.
  • The Land Use page states this as a general summary; the district tables control.

  front setback from township road centerline: 70 feet (from township road centerline) · 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

  Dwellings in the A-1 agriculture district in unincorporated LaSalle County, including Waltham township if zoned A-1

  • No height limit applies to non-dwelling buildings on zoning lots of one acre or more.
  • Dwellings are capped at 36 feet, and so are all buildings on lots under one acre.

  maximum building height for dwelling units: <= 36 feet (zoning lots under one acre, and all buildings used as dwelling units)

  “on zoning lots with less than one (1) acre of land area, and on all buildings used as dwelling units the building height shall not exceed thirty-six (36) feet in height.”

• Living in an RVLimited

  Living or sleeping in a recreational vehicle on private land in unincorporated LaSalle County, including Waltham township

  • Use is capped at 180 days in a calendar year.
  • Living or sleeping in an RV is not allowed on a parcel in a subdivision, an unincorporated platted town, or on a parcel with an existing residence, unless the ordinance otherwise permits it.

  RV living or sleeping period: <= 180 days per calendar year (not allowed in subdivisions, unincorporated platted towns, or on parcels with an existing residence unless otherwise permitted)

  “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.”

• Camping on your landLimited

  Temporary camping with a recreational vehicle or trailer on private land in unincorporated LaSalle County, including Waltham township

  • Living or sleeping use of an RV is capped at 180 days in a calendar year.
  • Camping and RV use in a subdivision, platted town, or on a parcel with an existing house is restricted by Sec. 4.22 unless otherwise permitted.
  • Campgrounds and transient or travel trailer camping are listed as special uses in some districts; that district list was not checked.

  RV living or sleeping period: <= 180 days per calendar year

  “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.”

• Septic permitRequired

  New or repaired private sewage disposal systems on land inside Waltham township

  • A completed application, the fee, and an onsite survey by health department staff are needed before a construction permit issues.
  • Application needs a plat of survey, a plot plan with setbacks and soil borings, and a completed soil investigation.

  “a permit for construction 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 inside Waltham township

  • The health department must be notified for a final inspection before the system is backfilled.
  • The county does not guarantee any system, and the inspection does not give any general or implied warranty.

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

• Off-grid sanitationLimited

  Homes in Waltham township that are not on public sewer

  • An individual system needs a health department permit and inspection before construction.
  • The system must meet current Illinois Department of Public Health standards, as confirmed at inspection.

  “the lasalle county health department inspection will result in a statement as to whether, or not, a private sewage disposal system and/or well meets current illinois department of public health standards”

• Mandatory utility hookupSewer (with conditions)

  Uses in the R-3 general residence district in unincorporated LaSalle County, including Waltham township if zoned R-3. Public sewer and water are required to serve uses there.

  • This applies only to the R-3 district, not to the whole township.
  • The text says public sewers and public water are required to serve all uses in R-3; it is not a general connection-when-available rule.

  “public sanitary sewers and public water supply are required to serve all uses within this district.”

• Subdividing landRegulated (with conditions)

  Dividing land in unincorporated LaSalle County, including Waltham township

  • The county asks landowners to contact the department before subdividing.
  • Every resulting lot must meet the bulk rules of its zoning district.
  • Splits must also meet the county subdivision ordinance and the Illinois Plat Act.

  “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)

  Private sewage disposal system permit fee for land in Waltham township; building permit fees were not captured

  • Payment is by check to the LaSalle County Health Department or online under the 'septic permit/training' fee type with a service fee for cards.
  • Building permit fee amounts were not found in the pages opened; a 2025 fee schedule was linked but not opened.

  private sewage disposal permit application fee: 230 USD

  “there is a two hundred thirty ($230.00) dollar application fee for a private sewage disposal system permit.”

• Permit processPartial

  Building permits for unincorporated land in Waltham township are submitted to the county Land Use office; septic permits go to the health department

  • Permit submittals go to the Land Use office at 119 West Madison Street, Room 107, Ottawa, phone 815-434-8666.
  • The health department septic process is separate; the full building-permit steps and forms were not reviewed.

  “permit submittals: lasalle county office 119 west madison street - room 107 ottawa, illinois 61350 phone: 815-434-8666”

Still unanswered

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

• Owner-builder exemption — Owner-builder exemption for homeowners building in Waltham township
• Certificate of occupancy — Certificate of occupancy for new homes in Waltham township
• Minimum dwelling size — Minimum dwelling floor area in Waltham township
• Lot coverage — Lot coverage limits in Waltham township
• Tiny homes — Tiny-home occupancy in Waltham 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.