Floodplain Regulations

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Floodplain Regulations (February 28, 2019)

Floodplain Development

Floodplain Permit Application must be submitted and approved by the Floodplain Administrator prior to all development activity to assure the County and the property owner that all applicable flood code standards have been met.

Sections 5.02-5.06 of Missoula County’s Floodplain Regulations detail permit requirements within the designated floodplain. Requirements for permits include any man-made change to real estate including, but not limited to:


  • Construction, reconstruction, repair, placement of a building, or any structural alteration to a building;
  • Substantial improvement of an existing building;
  • Installation of a manufactured home on a site, preparing a site for a manufactured home, or installing a travel trailer on a site for more than 180 days per year;
  • Installation of utilities, construction of roads, bridges, culverts or similar projects;
  • Construction or maintenance of levees or riprap;
  • Drilling, mining, filling, dredging, grading, excavating, paving, or other alterations of the ground surface;
  • Storage of materials including the placement of gas and liquid storage tanks; and
  • Channel modifications or any other activity that might change the direction, height, or velocity of flood or surface waters.

Floodplain permits are generally not required for routine maintenance of existing buildings; resurfacing roads; or gardening, plowing, and similar practices that do not involve filling, grading, or construction of levees.

Subdivision Development

Missoula County’s Subdivision Regulations require that proposed subdivisions that contain flood hazard area comply with Section 3.1.3 of the Missoula County Subdivision Regulations.

For more information regarding any development within or near a flood hazard area please contact Todd Klietz, Missoula County Floodplain Administrator, at (406) 258-4841 or by email at