What the Subdivision Review Program Does
The Subdivision Review Program reviews proposed land divisions for compliance with Montana sanitation requirements. Flathead County Environmental Health works under contract with the Montana Department of Environmental Quality to review eligible subdivision applications for sanitation facilities.
Sanitation review focuses on whether the proposed lots can be served by adequate water supply, wastewater treatment, solid waste disposal, and storm drainage systems. This review helps protect public health, groundwater, surface water, and future property owners before new parcels are created.
What Sanitation Review Looks At
Subdivision sanitation review is different from zoning, road review, addressing, floodplain review, or the Planning and Zoning subdivision process. Environmental Health review generally focuses on sanitation facilities and site conditions, including:
- Proposed drinking water source, such as a well or public water connection
- Proposed wastewater disposal, such as a septic system or public sewer connection
- Storm drainage and surface water considerations
- Solid waste disposal
- Lot layout, setbacks, replacement areas, and separation from wells, surface water, floodplains, and other features
- Whether the proposal meets applicable state sanitation laws and administrative rules
Before You Apply or Develop
Many properties need a review of their existing subdivision approval before a new home, additional dwelling unit, commercial use, well, or septic system can move forward. Existing approvals may include a Certificate of Subdivision Approval, commonly called a COSA, or older sanitary restrictions.
A COSA or previous subdivision approval does not replace the need for local permits. For example, a property owner may still need a septic permit before installing or modifying a drainfield.
If the proposed development does not match the approved lot layout or COSA language, a modified lot layout, COSA rewrite, or other review may be needed before construction or permitting can proceed.
Common Terms
- Certificate of Subdivision Approval (COSA)
- A sanitation approval issued through Montana DEQ. A COSA may describe the approved use of the property, water source, wastewater disposal method, and stormwater requirements.
- Modified lot layout
- A revised layout used when approved locations or features need to change but the written COSA conditions do not need to change.
- COSA rewrite
- A review used when the written COSA conditions need to change, such as changing the approved use or number of living units.
- Sanitary restrictions
- Restrictions that may appear on older parcels or parcels that were excluded from review. Environmental Health can help determine whether additional sanitation review is needed before water or wastewater facilities are developed.