A majority of high water bills are due to toilets that are leaking. Toilet leaks are often inaudible. Other things to check for are leaks in sprinkler systems, sump pumps that have water back-up systems, and dripping faucets.
It is important to determine and correct the problem because wasted water results in high bills. One way to check if you have a problem is to write down the six-digit number off the water meter (usually located in the basement of the house) before you go to bed at night. The following morning, go to the water meter and compare the readings. If the meter has moved while you were sleeping, that indicates something is using water. A more immediate check involves the red dial on the water meter. When the dial is spinning, water is going through the meter. The red dial should be still when there is no water usage.