If, without flushing, the color begins to appear in the bowl, you have a leak that should be repaired immediately. To cut down on waste water, put an inche or two of sand or pebbles inside each of two plastic bottles to weigh them down. Fill them with water and put them in your toilet tank, safely away from operating mechanisms. In an average home, the bottles may displace and save ten or more gallons a day. Even the smallest drip from a worn washer can waste 20 or more gallons a day.
Larger leaks can waste hundreds.
Leaks waste water 24 hours a day, seven days a week and often can be repaired with an inexpensive washer. Early morning is generally better than dusk since it helps prevent growth of fungus.