The water line between your meter and your house is out of sight, which is exactly why it gets ignored until it fails. Older lines, especially galvanized steel and early plastic, wear out after decades underground, and shifting soil or roots can crack newer ones.
The first sign is often the water bill. If usage climbs and nothing in the house has changed, water may be leaking before it ever reaches a faucet. Turning off every fixture and watching the meter's leak indicator is a quick test: if it still moves, water is going somewhere.
Second, a soft, soggy, or unusually green strip of lawn along the path of the line, especially in dry weather. Third, a drop in water pressure throughout the house. Fourth, rusty or discolored water, which can point to corroding pipe. And fifth, a sinkhole or depression forming over where the line runs.
Any one of these is worth a look. Small leaks can often be fixed by exposing and replacing a single section. When a line is old and failing in several places, replacing the whole run from the meter to the house is usually the better investment, and it ends the cycle of patching.
Either way, we locate the line, dig carefully to expose the problem, fix it, test it, and restore the yard, so the only thing you notice afterward is steady water pressure.