Code Information

Building Codes

The City of Missoula has adopted the following codes effective January 20, 2015.

  • 2012 International Residential Code (IRC)
  • 2012 International Building Code (Commercial)
  • 2012 International Energy Conservation Code (IECC)
  • 2012 Uniform Plumbing Code (UPC)
  • 2012 International Mechanical Code (IMC)
  • 2012 International Fuel Gas Code (IFGC)
  • 2014 National Electrical Code (NEC)


Please note the changes to the 2012 IRC concerning Carbon Monoxide Alarms Section R315.3. Where required in existing dwellings. Where work requiring a permit occurs in existing dwellings that have attached garages or existing dwellings within which fuel-fired appliances exist, carbon monoxide alarms shall be provided in accordance with section R315.1. 

It is advised that all contractors review the adopted codes pertaining to their specialty and become familiar with other possible changes not listed.

Snow Load

The snow load for the City of Missoula is 30 pounds per square foot and the wind load is roughly 90 miles per hour. See IBC 1609 or IRC 301.2 for exact number.

More Information

To purchase code books, visit the International Code Council.

Building Residential Occupancies on Hillsides or Slopes

R401.3 Drainage - Surface drainage shall be diverted to a storm sewer conveyance or other approved point of collection so as to not create a hazard. Lots shall be graded so as to drain surface water away from foundation walls. The grade away from foundation walls shall fall a minimum of 6" (152 mm) within the first 10' (3,048 mm). One exception is where lot lines, walls, slopes, or other physical barriers prohibit 6" (152 mm) of fall within 10' (3,048 mm), drains or swales shall be provided to ensure drainage away from the structure.