The supply guarantee includes that there is sufficient
water in quantity and quality for every customer at any
given time [11]. Drinking water quality underlies various
parameters, but in general it should guarantee potable,
wholesome and palatable water [12]. The sustainability
aspect means continuous supply of safe and drinkable water
to the future generations. Customer service means that
customers have easy access to the quality water at an
acceptable price and the customer complaints are addressed
properly [11]. Finally, the economic efficiency states that
the fees for the water should cover the cost of the water
supply