It is easy to tell if there is any water leakage. Just make sure all water is turned off inside house. Then go watch the water meter. If the meter number reading is still moving, then there is a confirmed leakage.

If you can ensure turning off water in house and the meter not moving at all. Then you can try to be sure by staying in hotel for one day, then compare the meter before and after, has the number increased? If no one at home, then water meter should not increase at all. If it increases, something is using the water.

Then just break it down by monitoring every hour etc, eventually will find the source.