What one needs to retire near fresh water (9)
I believe the answer is:
nightwear
'what one needs to retire' is the definition.
(retire can mean to go to bed)
'near fresh water' is the wordplay.
'near' becomes 'nigh' (synonyms).
'fresh' indicates an anagram (a fresh re-ordering of the letters).
'water' with letters rearranged gives 'twear'.
'nigh'+'twear'='NIGHTWEAR'
(Other definitions for nightwear that I've seen before include "this brings bed to mind?" , "Bedroom items" , "habit of one retiring" , "evening dress" , "What's on after the watershed" .)