It could be spring water, child (6)
I believe the answer is:
season
'it could be spring' is the definition.
(I know that spring is a type of season)
'water child' is the wordplay.
'water' becomes 'sea' (the sea is water).
'child' becomes 'son' (male child).
'sea'+'son'='SEASON'
(Other definitions for season that I've seen before include "Salt, maybe" , "' - - of mists ...' (Keats)" , "To dry (wood) for use as timber" , "instruction in recipe" , "Add flavouring" .)