Evian or Perrier (3)
I believe the answer is:
eau
'evian or perrier' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for eau that I've seen before include "Popular toilet water - . . . de Cologne" , "French water - de Cologne?" , "Water in France" , "-- de vie" , "Quick to notice things" .)