Firstly, make sure that you turn off any and all items in use such as dishwasher, laundry washer, sprinklers, etc. If you have a water meter at your property corner or other location on your property itself, it can be checked for leakage by looking at the face of the meter and the dials that are on it. If water is not being used, the leak detector dials on your water meter will be completely still and have no movement. If the dials are moving/spinning and you are not using water, it indicates that water is flowing through the meter and causing usage to count. In some cases, if the leak is very fast, the dials of the meter can become damaged and not correctly show the moving/spinning usage, so we advise you to also listen for the sound of flowing water through the pipeline. Another option is to take down your meter reading and then without using any water for 2 hours, recheck the meter reading to see if it has gone up in usage. In most cases, a slow leaks common cause is a leaking toilet flapper.