In 2010, New Jersey legislators introduced William's Law, a bill that would set new standards in pool safety throughout the state. To date, there has been no update on its status. If passed, it would set residential swimming pool and spa barriers at five feet, regardless of the barrierâ¤™s construction.For now, the state code provides for the construction of such a barrier with a minimum height of four feet above grade. If the fence or barrier is mounted on the pool itself, a four-inch clearance between the top of the pool and bottom of the barrier is required. Spacing between fence members must be no wider than 1.75 inches for fences with 44-inch segments or less, and no 4 inches for fences with 45-inch segments or more.