Call your plumber. If your toilet is not one of the newer, water-saving ones that use about 1.6 gallons a flush, install a toilet tank water saver which will save you several gallons of water a day. You can use a toilet tank dam which eliminates corners of the tank, making it smaller, and holds back water when it is flushed. You also can use a plastic displacement bag or a plastic milk bottle. Simply fill with water and place inside the tank.
Less water is used when the toilet is flushed.
A toilet tank dam or displacement bag can reduce water use by 10 to 20 percent. Most hardware, home improvement or plumbing supply stores carry these items. Faucets that are allowing too much water to flow through, should be installed with low-flow aerators. Remember that the rate of flow, though, depends on water pressure. Different flows from different faucets may be desirable.