Turn off all faucets inside and outside of your home.
Record your meter reading.
Wait 2 to 3 hours without using any water. During this time period that includes not flushing toilets.
Record your meter reading again and compare to the previous reading that you recorded.
If the reading has increased you may have a leak and may need to contact a plumber to repair the leak or you may repair the leak yourself. If the 2 recorded readings are the same then you do not have a leak.