Read your meter after 15-30 minutes. If the needle has moved, you have leak. To determine if the leak is indoors or out, turn off the house valve. If the needle continues to move, your leak is in between the house and the meter. If the needle stops, then the leak in inside your house.
Toilets are the most common and biggest water wasters.
Check with your local plumbing or hardware store for advice, or click on the toilet for more details. Most showerheads that were manufactured before 1994 use 5 gallons per minute. After 1994, federal plumbing standards required showerheads to flow no more than 2.5 gallons per minute. In homes, some showerheads may have been converted from 5 gallons per minute to 2.5 gallons per minute by inserting a small plastic disk with a hole in it into the showerhead. This method has been received by the public with mixed satisfaction.