No private swimming pool, exclusive of portable swimming pools with a diameter of less than twelve feet or an area of less than 100 square feet shall be allowed in any commercial or residential district, except as an accessory use and unless it complies with the following conditions and requirements:
(a) The pool is intended and shall be used solely for the enjoyment of the occupants of the principal use of the property on which it is located;
(b) It may not be located closer than ten feet to any property line; and
(c) The swimming pool or the entire property on which it is located shall be walled or fenced to prevent uncontrolled access by children from the street or from adjacent properties. Such fence or wall shall not be less than forty-two inches in height with a gate and lock, and maintained in good condition.