Skip to contentSkip to left sidebar Skip to right sidebar Skip to footer

Codes & Design Criteria

The State of New Hampshire (under RSA 155-A) has adopted a set of Building Codes administered by the International Code Council (ICC) and the National Fire Protection Agency (NFPA). All construction must be in conformance with these codes, and other applicable State and Town Statutes (Laws), Codes, Ordinances, Regulations, and Rules including but not limited to:

Building related codes:

  • 2017 NFPA 70 National Electrical Code
  • 2018 International Building Code
  • 2018 International Residential Code
  • 2018 International Existing Building Code
  • 2018 International Mechanical Code
  • 2018 International Plumbing Code
  • 2018 International Energy Code
  • 2018 ICC A117.1 Accessibility Standards
  • 2018 NFPA 54 Fuel Gas Code
  • 2018 NFPA 101 Life Safety Code

Town of Alton Building Code:

  • Town of Alton Zoning Ordinance
  • Town of Alton Site Plan Review and Subdivision Regulations
  • NH Department of Environmental Services (DES) Subsurface, Shoreland, and Wetland Statutes and Rules
  • Town of Alton Health Regulations
  • NH State Public Health Statutes and Rules

Climactic and Geographical Design Criteria for the Town of Alton are as follows:

  • Ground Snow Load for the Town of Alton is 90lbs per square foot (90pg) at 900’ of elevation above sea level (ASL).
  • Wind Design Speed is 100 mph.
  • Seismic Design Category is C.
  • Weathering design temperature is 0 degrees F.
  • Frost line depth is 48”.
  • The Winter Design Temperature is -3 degrees F.
  • Ice Barrier Layer is required.
  • Flood Hazard: The effective Flood Insurance Rate Maps (FIRM) are Community-Panel numbers 330001-10B, 15B, 20B, 30B & 35B.The effective date is May 17, 1988. Although the FIRM for the majority of the state has been updated, they have not been done yet for Belknap County.
  • Air Freezing Index is 2000.
  • Mean Annual Temperature is 45.2 degrees F.
  • Exposure Category is B unless determined otherwise.
  • The Mean High Water Mark (MHWM) or “Reference Line” for Lake Winnipesaukee is 504.32’ ASL. Halfmoon Lake is 640’, Hill’s Pond is 809’, and Sunset Lake is 808’.

Information about other waterbodies in Alton can be obtained from the Building Department or online at:

NHDES Consolidated List of Waterbodies Subject to RSA 483-B, the Shoreland Water Quality Protection Act (SWQPA)