It's usually given free of charge, 4 letters
Bathroom cupful, 8 letters
Cheap Perrier alternative, 8 letters
Drinking source, 8 letters
Evian alternative, 8 letters
Faucet output, 8 letters
Fluid from a faucet, 8 letters
Free alternative to Evian, in a restaurant, 8 letters
It may be filtered, 8 letters
It often just goes down the drain, 8 letters
Meaning of one on the city, in diner lingo, 8 letters
No-frills beverage, 8 letters
Perrier alternative, 8 letters
Restaurant freebie, 8 letters