We part at revolting Adam's Ale (3,5)
I believe the answer is:
tap water
'adam's ale' is the definition.
'we part at revolting' is the wordplay.
'revolting' indicates an anagram.
'we'+'part'+'at'='wepartat'
'wepartat' with letters rearranged gives 'TAP-WATER'.
(Other definitions for tap water that I've seen before include "Domestic drink" , "still running?" , "Best and cheapest drink?" , "Ordinary drink" , "Vital liquid from a sink unit" .)