One managed to hold water (4)
I believe the answer is:
rain
'water' is the definition.
(I know that rain is a type of fresh water)
'one managed to hold' is the wordplay.
'one' becomes 'i' (Roman numeral).
'managed' becomes 'ran' (both can mean organised or was in charge of).
'to hold' indicates putting letters inside.
'i' going within 'ran' is 'RAIN'.
(Other definitions for rain that I've seen before include "previous rule?" , "See 12" , "downfall?" , "Fall in large quantities" , "Wet weather" .)