What are the pool fence and barrier requirements in Massachusetts?

The tenth edition of 780 CMR adopts the 2021 International Swimming Pool and Spa Code with Massachusetts amendments (tenth edition overview). In the base volume, section 3109.1 says "the design and construction of swimming pools, spas and hot tubs shall comply with the International Swimming Pool and Spa Code" and points public and semi-public in-ground pools to M.G.L. c. 140, § 206 for their enclosures (780 CMR chapter 31). In the residential code that governs one- and two-family homes, section R327.1 says the same, "the design and construction of pools and spas shall comply with the International Swimming Pool and Spa Code", and adds that the wiring must follow 527 CMR 12.00, the Massachusetts Electrical Code, and a gas-fired pool heater 248 CMR, the plumbing and gas code (780 CMR 51.00 chapter 3). The barrier rules are therefore the ISPSC's section 305, read with the state's amendments and the town's own regulations.

Section 305.2 of the ISPSC requires outdoor pools and spas, and indoor swimming pools, to be surrounded by a barrier. The top of the barrier must be at least 48 inches above grade measured on the side facing away from the pool, all the way round and for 3 feet out from the barrier. The gap under the barrier may not exceed 2 inches over grass or gravel, or 4 inches over a solid surface such as concrete. No opening in the barrier may let a 4-inch sphere through; a solid barrier may not have indentations or protrusions that make handholds or footholds. Where a fence has horizontal and vertical members and the horizontals are less than 45 inches apart, the horizontals go on the pool side and the verticals may be no more than 1¾ inches apart; where the horizontals are 45 inches or more apart, verticals may be up to 4 inches apart. Chain link openings may be no more than 1¾ inches, diagonal lattice openings no more than 1¾ inches at no more than 45 degrees, and pool equipment outside the barrier must sit at least 36 inches from it (ISPSC 305.2).

Mesh fences are allowed as a barrier under section 305.2.4 if installed to the manufacturer's instructions: the bottom no more than 1 inch above the deck or grade, no more than 4 inches of lift, no 4-inch sphere under any panel, attachment devices at least 45 inches up, and the inside of the mesh at least 20 inches from the water's edge; a mesh fence may not be installed on top of an on-ground pool (ISPSC 305.2.4).

Pedestrian gates and doors in the barrier must open outward, away from the pool, be self-closing and self-latching, and be able to take a lock; utility gates not meant for people stay locked when not in use, and on a double gate one leaf is fixed and the other self-latches. The latch release, where it is reachable from outside and not self-locking, must be at least 54 inches above grade at a residential pool; a self-locking release (a key, code or electronic opener) may be no higher than 54 inches; and where the only release is on the pool side of the gate it must be at least 3 inches below the top of the gate, with no opening bigger than ½ inch within 18 inches of the latch (ISPSC 305.3).

Where a wall of the house forms part of the barrier and a door, gate or window opens straight onto the pool, section 305.4 requires one of: an audible water-hazard entrance alarm, listed to UL 2017, on every such door, gate and window with a sill lower than 48 inches, with the deactivation switch at least 54 inches up; a safety cover listed to ASTM F1346 on the pool or spa; or an approved equivalent such as self-closing, self-latching doors (ISPSC 305.4). Section 305.1 also lets a spa or hot tub with a lockable ASTM F1346 safety cover, or a pool with a powered ASTM F1346 safety cover, skip the barrier sections 305.2 to 305.7 altogether.

An on-ground residential pool's own wall can be the barrier under section 305.5 if its bottom is on grade, its top is at least 48 inches above grade all round, the manufacturer allows it, and the ladder or steps can be locked, secured or removed so that no 4-inch sphere passes the opening they leave; a barrier mounted on top of the pool wall counts the same way, installed to the manufacturer's instructions (ISPSC 305.5). The construction site of an in-ground pool must be fenced at least 4 feet high from the first excavation until the permanent barrier is finished (ISPSC 305.1.1). A prefabricated pool less than 24 inches deep needs no building permit at all under the residential code's exemptions (780 CMR 51.00 R105.2).

The town issues the permit and inspects the barrier, and several publish their own pool rules. Mashpee requires a permit for above-ground and in-ground pools, inspects the rough after the wiring inspector has checked bonding, wants the pool as-built uploaded before the final, and lists alarms, retractable covers and fencing among the final inspection items (Mashpee FAQ). Grafton posts swimming pool barrier requirements with its pool application, Hamilton a page on pool, hot tub and spa covers and fencing, and North Reading its updated pool and spa regulations (Grafton Building Permits; Hamilton Building Department; North Reading FAQ). Swansea states that a fence is required around an in-ground pool under the state building code, four feet high and non-climbable (Swansea Permits). Because the code's minimums are statewide and the town's regulations may add to them, the town page is the place to check before the pool goes in.