Restaurants make the most of liquid assets

SHOULD price-gouging restaurateurs who bottle and sell their own tap water at exorbitant prices not also charge their gullible customers pro-rata each time they flush the restaurant toilet?

After all, the water is from the same source.

Surely the practice of passing off water as being other than from a municipal reservoir, from one part of a business premises could be extended, with impunity, to all parts of that premises.