Bottled water is so expensive. The tap water is safe to drink in almost all areas of the country. (Check the government reports on your local water tests). I keep a jug of tap water in the refrigerator so it's always cold and I use lots of ice. I always carry a refillable plastic bottle of ice water whenever I step foot out of the house. Water is included with our rent, so I'm saving "buckets" of money by drinking tap water instead of bottled water.
I add a splash of lemon or lime juice for flavor most of the time.