55 Pa. Code § 3800.106 – Swimming.

(a) Above-ground and in-ground outdoor pools shall be fenced with a gate that is locked when the pool is not in use.
(b) Indoor pools shall be made inaccessible to children when not in use.
(c) A certified lifeguard shall be present with the children at all times while children are swimming.
(d) The certified lifeguard specified in subsection (c) may not be counted in the staff to child ratios specified in § § 3800.54 and 3800.55 (relating to child care supervisor; and child care worker).

This section cited in 55 Pa. Code § 3800.302 (relating to exceptions for outdoor and mobile programs).