To check for leaks, put a little food coloring in your toilet tank. Leave alone for several minutes. If the food coloring color appears in the toilet bowl you have a leaky gasket. Fix as soon as possible. Take shorter showers.
Long showers waste five to ten gallons every minute.
Install water-saving devices for your showerhead and toilet. Turn off the water while brushing your teeth or shaving. Keep a bottle of drinking water in the refrigerator. This ends the wasteful practice of running tap water to cool it off for drinking. Use your automatic dishwasher only for full loads.