Zoning, building permits and septic rules in Town of Ismay, Montana

Rules another office applies inside Town of Ismay

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

• Building permitLimited

  A single-family residence inside Ismay town limits.

  • A state building permit is not required for a single-family residence unless a local-government jurisdiction requires one by ordinance or resolution.

  “A building permit is not required for a single family residence, unless you live inside a local government's jurisdiction”

• Building code adoptedAdopted (with conditions)

  Residential and commercial buildings inside Ismay town limits that are subject to Montana's uniform state building code.

  • Cities, counties, and towns may elect to enforce certified local building codes in whole or in part.

  “a uniform state building code, which is enforced statewide”

• InspectionsLimited

  Projects inside Ismay town limits that require state building-code permits.

  • The cited state program describes inspection as part of its statewide code enforcement; the applicable permit category and any certified local enforcement program must be determined for the particular project.

  “issuing permits and performing inspections.”

• Who permits septicMixed (with conditions)

  Sanitation review for qualifying subdivisions inside Ismay town limits.

  • DEQ is the reviewing authority unless it has certified a local department or board of health as the local reviewing authority for the subdivision.

  “If the department has certified a local department or board of health to review subdivisions”

• Off-grid sanitationLimited

  Off-grid water supply or sewage disposal proposed in a qualifying subdivision inside Ismay town limits.

  • The subdivision must be reviewed and approved by DEQ or a DEQ-certified local reviewing authority before facilities for water supply or sewage disposal are erected or used.

  “a COSA must be issued for the lot(s) prior to developing facilities that require sewer or water.”

• Subdividing landRegulated (with conditions)

  Divisions of land inside Ismay town limits that create parcels of less than 160 acres for sale, rent, lease, or other conveyance, including condominiums and manufactured-home or recreational-vehicle parks.

  • Numerous statutory exemptions may exclude some divisions from surveying requirements, local subdivision review, or both.

  parcel size threshold: < 160 acres (For sale, rent, lease, or other conveyance; statutory exemptions may apply)

  “All divisions of land creating parcels less than 160 acres in size”

• Permit feesPublished (with conditions)

  State sanitary subdivision review applicable to qualifying subdivisions inside Ismay town limits.

  • The official legislative permit index directs applicants to the fee schedules in the rules or the fee checklist with application materials.

  “Subdivision Review Fee Calculation - Effective May 30, 2025”

• Permit processPublished (with conditions)

  Sanitary subdivision applications for qualifying subdivisions inside Ismay town limits.

  • If DEQ has certified a local department or board of health to review subdivisions, the application must be submitted to that local reviewing authority.

  “the application must be submitted to the local reviewing authority.”

Still unanswered

We looked and could not find an official answer yet. Silence is not permission; ask Town of Ismay or Custer County directly.

• Owner-builder exemption — Owner-built residential construction inside Ismay town limits.
• Local zoning — Land inside Ismay town limits.
• Zoning districts — Land inside Ismay town limits.
• Minimum dwelling size — Dwellings inside Ismay town limits.
• Minimum lot size — Lots inside Ismay town 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.