On a property with a long service line and a big lot, a leak can run for months before anybody notices. The water bill is usually the first clue.
A test you can do in a minute
Turn off every tap and anything that uses water, then check the meter. If it is still moving, water is escaping somewhere. On a well, the equivalent sign is the pump switching on and off when nobody is using anything.
Outside as well as inside
With long runs between the road, the house and any outbuildings, plenty of Johns Island leaks are underground rather than in a wall. A patch of ground that stays soft or looks greener than everything around it is worth mentioning when you call.
Found without opening walls
Listening equipment and thermal imaging narrow it down first, so anything we open is small and deliberate. That matters in older homes where making good afterwards is the expensive part.
Why it is worth dealing with quickly
A slow leak stops being a plumbing problem fairly quickly and becomes flooring, cabinets and framing instead. In our humidity it also encourages rot, particularly under a raised house.