Pool due to a bad leak? (4)
I believe the answer is:
lake
'pool' is the definition.
(I've seen this before)
'a bad leak?' is the wordplay.
'a bad' indicates anagramming the letters.
'leak' with letters rearranged gives 'LAKE'.
'due to' is the link.
(Other definitions for lake that I've seen before include "Eg, Windermere" , "Inland body of water" , "Purplish-red pigment" , "holiday up north" , "A pigment; a body of water" .)