Sanitation in Subdivisions

There are several ways that a parcel is created and this affects the requirements for developing the property.

  1. Properties under 20 acres may have a Certificate of Subdivision Approval (COSA) which means the parcel has been reviewed by Montana Department of Environmental Quality (DEQ).  These parcels have an approved site plan showing septic and well locations.  You should receive a copy of this plan when you purchase the property.
  2. A parcel may have been created with a restriction that does not allow a building with water or sewer.  Such parcels must be reviewed by DEQ to “lift this restriction”.
  3. A parcel may also have been created prior to subdivision regulations. In these cases, local review by the Environmental Health Department is required to determine if septic and well sites are possible. Additional tests and engineering services may be required.
  4. Parcels over 20 acres in size are also subject to local review.  Visit the Montana Department of Environmental Quality website for more information.