Permanent and portable swimming pools and tennis courts which are accessory to a residential use shall be erected on the same lot as the principal use.

Every swimming pool, or the premises upon which the pool is located, shall be completely enclosed by a fence not less than 3 1/2 feet in height with no opening therein other than doors or gates. The height of the fence to be erected shall be measured from a point at ground level, which point shall be five feet outside or beyond the fenced area. The fence or wall shall be so constructed as not to have holes or gaps exceeding four inches in at least one dimension.

All gates or door openings through the fence or enclosure, referred to above, shall be kept securely closed and locked at all times when the swimming pool is not in use. Access ladders or steps used in connection with the swimming pool shall be removed when such pool is not in use.

Fences and walls constructed for swimming pools and tennis courts shall comply with the regulations provided in subsection 40-8.4.