Hillsborough County, NH Swimming Pools & Spas: Fencing Requirements (2026)

Pool barrier regulation in Hillsborough County is handled at the state and municipal level, not the county. RSA 155-A establishes the New Hampshire State Building Code as a single, statewide minimum standard. Per RSA 155-A:1, IV, the State Building Code adopts the International Residential Code (IRC), International Building Code (IBC), International Existing Building Code, and International Swimming Pool and Spa Code (ISPSC), all with New Hampshire-specific amendments adopted by the State Building Code Review Board. For one- and two-family dwellings, swimming pool barrier requirements are in IRC Appendix AG (section AG105). AG105.2 requires that any pool with water depth greater than 24 inches be enclosed by a barrier at least 48 inches high, measured on the side away from the pool. Openings in the barrier must not allow passage of a 4-inch-diameter sphere. Horizontal members on the pool side must be spaced at least 45 inches apart, or the barrier must use mesh meeting specific spacing rules. Gates must open outward away from the pool, be self-closing, and self-latching, with the release mechanism at least 54 inches above the bottom of the gate. Where the dwelling wall serves as part of the barrier, doors with direct access to the pool must have an alarm or self-closing/self-latching device. Hot tubs and spas with a safety cover meeting ASTM F1346 are exempt from the perimeter barrier requirement. Building permits, plan review, and inspections are issued by the local code official in each Hillsborough County municipality (Manchester, Nashua, Merrimack, Hudson, etc.). RSA 155-A:7 makes the State Building Code the minimum statewide standard - municipalities may adopt additional local amendments but cannot weaken the state code.