Boulder County, CO Swimming Pools & Spas: Fencing Requirements (2026)

Boulder County Community Planning & Permitting administers the Boulder County Building Code, which adopts the 2021 International Residential Code with local amendments effective March 31, 2025. Under IRC Appendix G (and the IRC's residential pool sections), permanent outdoor swimming pools, hot tubs, and spas with water deeper than 24 inches require an enclosing barrier. The barrier must have a top height of at least 48 inches measured from the side facing away from the pool, with the bottom no more than 2 inches above grade for solid surfaces (4 inches if the surface beneath is non-solid). Openings must not allow passage of a 4-inch-diameter sphere; for picket fences, spacing between members is limited so that a 1-3/4-inch sphere cannot pass when the top horizontal is less than 45 inches from grade. Pedestrian access gates must open outward away from the pool, be self-closing and self-latching, and where the latch is less than 54 inches from the bottom of the gate, the latch must be on the pool side at least 3 inches below the top, with no openings within 18 inches of the latch. Where a wall of a dwelling forms part of the barrier, doors with direct access to the pool must have an alarm or a self-closing/self-latching device at least 54 inches above the floor. Hot tubs and spas with locked safety covers complying with ASTM F1346 are exempt from the barrier requirement. A building permit is required for pool, spa, and barrier construction.