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FAQs

You can submit a land research request form, and an environmental health specialist will be with you in a few weeks. Be specific on the form with what your future plans for the property are

  • A COSA, or Certificate of Subdivision Approval, is a document that is created by Montana Department of Environmental quality (DEQ) when a parcel is divided into parcels smaller than 20 acres. This applies to ALL divisions of land, not just those on named subdivisions. This document contains approval for wastewater facilities on each lot within the division.
  • If your property is <20 acres, you may submit a land research request form and request a copy of the COSA. Be sure to be specific with what your plans are with the property to ensure we get you the best response.

  • If you have an existing home connected to city sewer or with a valid septic permit, you may apply for a vacation rental license at flatheadhealth.org/environmental-health/public-accommodations.
  • If you are wishing to construct another dwelling on your property and rent it out as a vacation rental, you must first determine whether your property is approved for a second dwelling. You can determine septic approval by submitting a land research request form on this website. You will also need to determine zoning approval, which can be done by contacting the Flathead County Planning and Zoning office.
  • If your property is approved for a second dwelling, you may submit an application, and our department will look at your existing septic permit to determine whether or not it is sized for the dwelling, or if a separate septic system will be required.

If an approved public municipality or sewer district sewer line is readily available within a distance of 200 feet of the property line and the owner (publicly owned entity) approves the connection, the applicant must connect. A connection is considered as not readily available if:

1) The cost of constructing the connection to the public sewer is greater than three times the cost (3:1 cost analysis) of installing an onsite wastewater treatment system that could be approved for the site (Construction costs only: Costs related to annexation, such as road improvements and sidewalks, are not relevant to the determination), or

2) Connection to the public system is physically impractical, or

3) Necessary easements cannot be obtained.

4) The publicly owned entity is notified of the Department’s decision and concurs with the septic system installation or repair approval.

  • It is best to receive septic approval prior to drilling your well. Sometimes, environmental factors may limit locations of your septic system.

It is advised that you get septic approval prior to building your house. Sometimes, environmental factors may limit locations of your septic system.

  • Septic applications expire within 1 year.
  • Septic permits must be paid for within 1 year of their creation. The septic permit is issued after it is paid for. Septic systems must be installed and inspected within 1 year of their issuance.
  • State approvals of lots- Certificate of Subdivision Approvals (COSAs) are valid for the life of the property, however all septic systems must be installed according to current Flathead County Regulations and Construction Standards.
  • On-site evaluations are valid for 1 year, however, all septic systems must be installed according to the current Flathead County Regulations and Construction Standards.

  • Septic systems must be put into use within 3 years of installation. Systems older than 3 years must be re-inspected to insure proper function in accordance with current Regulations and Construction Standards.

  • Contact your local water district to see if you can connect to city water. If you cannot, the Montana Department of Natural Resources and Conservation (DNRC) must be contacted to obtain water rights to drill a well. If you have a previous approval (COSA) (most properties <20acres) on your property, be sure to install the well in the approved location.

  • First, you should determine whether your property is approved for a second dwelling. You can determine septic approval by submitting a land research request form on this website. You will also need to determine zoning approval, which can be done by contacting the Flathead County Planning and Zoning office.
  • If your property is approved for a second dwelling, you may submit an application, and our department will look at your existing septic permit to determine whether or not it is sized for the dwelling, or if a separate septic system will be required.

  • If you wish to add an addition, you will need to make sure the total new number of bedrooms will comply for the number of bedrooms listed on your existing septic permit. You can look up your existing permit on the Flathead County GIS Interactive Mapping Portal. If you cannot locate the permit on GIS, you may submit a land research request form on this website.
  • If you wish to create a shop apartment, you should first determine whether your property is approved for a second dwelling. You can determine septic approval by submitting a land research request form on this website. You will also need to determine zoning approval, which can be done by contacting the Flathead County Planning and Zoning office.
  • If your property is approved for a second dwelling, you may submit an application, and our department will look at your existing septic permit to determine whether or not it is sized for the dwelling, or if a separate septic system will be required.

  • If you notice that your septic system is failing, you should contact our office immediately and submit an application. You will also need to hire a licensed septic installer to repair or replace your system.

  • Constructing a single RV site would be considered adding a dwelling to your property. You would need to first determine whether your property is approved for a second dwelling. You can determine septic approval by submitting a land research request form on this website. You will also need to determine zoning approval, which can be done by contacting the Flathead County Planning and Zoning office.
  • If your property is approved for a second dwelling, you may submit an application and our department will look at your existing septic permit to determine whether or not it is sized for the dwelling, or if a separate septic system will be required.
  • Constructing two or more RV sites requires you to go through Subdivision Review. You will need to hire a consultant or engineer to help you submit the subdivision form to the DEQ, and perform the required environmental analysis and design. After the subdivision is approved by the DEQ, you may submit an application for a septic permit to the county.

  • You should first submit a land research request form and ask “what is my property approved for?” Be specific on what your intended plans for the property are.

Page Last Updated: Feb 9, 2024