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

Rules another office applies inside Marengo Township

Marengo 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 code adoptedAdopted (with conditions)

  New building permit applications for unincorporated land inside Marengo township, reviewed by the McHenry County Planning & Development Building Division

  • Applies to all new building permit applications from January 1, 2023 onward.
  • Applies only to unincorporated areas; villages and cities set their own codes.
  • The 2021 ICC codes and 2020 NEC are the codes named on the county page.

  ICC code edition: 2021 edition · NEC edition: 2020 edition

  “effective january 1, 2023, all new building permit applications will be reviewed for compliance with the 2021 icc codes and the 2020 nec.”

• Local zoningPresent (with conditions)

  Unincorporated land inside Marengo township's limits (not the City of Marengo): McHenry County's Unified Development Ordinance zoning applies because no township zoning ordinance was located

  • Applies only to unincorporated land; property inside a village or city is handled by that municipality, per the county planning page.
  • Treated as county zoning applying in the absence of a township ordinance; not confirmed that Marengo township has no zoning of its own.
  • Specific district standards are not stated on the page cited here.

  “While the Plan and Map is a policy document, it does not directly regulate the use of land in the Township. Formal regulation and zoning classification is implemented through the enforcement of ordinances, such as the McHenry County zoning and subdivision ordinances, and the decisions of the County Zoning Board of Appeals and County Board.”

• Zoning districtsPublished

  Zoning district lookup for unincorporated land inside Marengo township

  • The district map is an interactive GIS tool; the district list was not read.
  • Districts apply only to unincorporated land.

  “interactive gis map and zoning district look-up”

• Who permits septicCounty (with conditions)

  Onsite wastewater (septic) systems on any land inside Marengo township, administered by the McHenry County Department of Health, Environmental Health Division

  • Governed by the McHenry County Public Health Ordinance; no township septic authority was found.
  • Installations, repairs and modifications must be done by Illinois Department of Public Health licensed septic system installation contractors, per the county septic page.

  “a permit is required from the mchenry county department of health to install, modify, alter, extend, repair, replace or abandon a septic system in mchenry county.”

• Septic permitRequired

  Installing, modifying, extending, repairing, replacing or abandoning a septic system on land inside Marengo township

  • Permit issued by McHenry County Department of Health, not the township.
  • Applications may be submitted by mail or in person at the Environmental Health Division.
  • Site evaluation with a soil boring report by a certified soil classifier may be required for a new residence.

  “a permit is required from the mchenry county department of health to install, modify, alter, extend, repair, replace or abandon a septic system in mchenry county.”

• Permit feesPublished

  County Planning & Development permit fees for unincorporated land inside Marengo township

  • A new fee schedule takes effect July 1, 2026, per the county page; the amounts were not opened.
  • Fees for septic and well permits are set by the McHenry County Department of Health and were not verified.

  fee schedule effective date: 2026-07-01 date

  “codes, regulations and ordinances new fee schedule effective july 1, 2026”

• Permit processPublished

  County permit application process for unincorporated land inside Marengo township

  • Applications are filed through the county's online permit management system.

  “online permit management system; apply, schedule communicate 24/7”

Still unanswered

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

• Building permit — Whether a building permit is required for new construction inside Marengo township
• Owner-builder exemption — Owner-builder permit exemption for homeowners building on unincorporated land inside Marengo township
• Certificate of occupancy — Certificate of occupancy for new homes on unincorporated land inside Marengo township
• Minimum dwelling size — Minimum dwelling size in McHenry County's unincorporated zoning districts inside Marengo township (main single-family residential and agricultural districts not verified)
• Minimum lot size — Minimum lot size in McHenry County's unincorporated zoning districts inside Marengo township (main single-family residential and agricultural districts not verified)

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.