This is the 8906th most frequent Russian word.
протекающую
"Протекающую" means "leaking" or "flowing" depending on context.
This usage of 'протекающая' describes water that is leaking or flowing as a characteristic of the pipe.
В комнате была вода, протекающая из трубы.
There was water in the room, leaking from the pipe.
Here, 'протекающей' refers to the roof tiles that are allowing water to pass through.
На крыше обнаружили проблему с протекающей черепицей.
They discovered an issue with the leaking roof tiles.
'Протекающей' in this sentence describes the radiator that has a leak, highlighting its current state of the issue.