Raging fire following a question getting source of water (7)
I believe the answer is:
aquifer
'source of water' is the definition.
(water-bearing rock)
'raging fire following a question' is the wordplay.
'raging' indicates anagramming the letters.
'following' says to put letters next to each other.
'question' becomes 'qu'.
'fire' with letters rearranged gives 'ifer'.
'a'+'qu'='aqu'
'ifer' put after 'aqu' is 'AQUIFER'.
'getting' acts as a link.
(Other definitions for aquifer that I've seen before include "it holds water" , "Water-bearing stratum of permeable rock" , "Rock containing water" , "Water-bearing layer" , "Water-holding rock" .)