Text in force at 25-153: from 25-115, effective 2 Aug 2004.
[Each fuel tank filler connection must prevent the entrance of fuel into any part of the airplane other than the tank itself. In addition-- ]
(a) [Reserved.]
(b) Each recessed filler connection that can retain any appreciable quantity of fuel must have a drain that discharges clear of each part of the airplane;
(c) Each filler cap must provide a fuel-tight seal; and
[(d) Each fuel filling point must have a provision for electrically bonding the airplane to ground fueling equipment.]
69 FR 40527 · Source