No water anywhere in the house, or water surfacing in the yard, usually points at the same piece of pipe: the service line running from the street to the building. The first job is not to dig. It is to work out whether the problem sits on your side of the curb stop or the water system's, because that decides who fixes it and who pays for it.
One fixture, or the whole house?
If one faucet has nothing and the rest of the house is fine, that is a fixture or a branch inside the building, and it is a plumber's call. If every tap in the house is dry, or the pressure fell off a cliff everywhere at once, the problem is at or before the point where the service enters the building.
Is it just you?
Ask a neighbor before anything else. If the houses around you are out too, it is the main, and the main belongs to whoever supplies your town. That is also the fastest fix available to you, because the system will already have crews on it.
If you are not certain who supplies your water, we publish it town by town: who supplies your water in New Jersey, with the share of each municipality that actually sits inside a delivery area. It matters more than people expect, because a number of towns around here have no public water at all. In Sussex County two municipalities have none, and in Warren County four. If yours is one of them, you are on a well, and no water is a pump, pressure tank or power problem rather than a buried pipe. That is a licensed well and pump contractor, not us, and it is worth knowing before you start calling excavators.
Water coming up where it should not
A service line leak announces itself above ground long after it starts. What people notice: a soft or soggy patch of lawn in a dry week, water seeping at the curb or edge of the road, a spot that stays green while the rest of the grass browns, and in winter a bare or melted patch in otherwise even snow. Around a foundation it can show up inside as unexplained dampness before anything appears in the yard.
The meter test tells you which side. Shut off every fixture in the house, including anything automatic, then look at the meter. If the dial or the leak indicator is still turning, water is moving through it, and the leak is downstream of the meter. Where your meter lives decides what that proves, and that is its own piece of plumbing geography: in a pit near the curb, nearly the whole buried run is measured, while a meter inside the basement means the buried run is upstream and a leak out there can run for months without touching your bill. We went through both arrangements in the water bill that doubled with no leak found.
The curb stop is not yours to turn
The curb stop is the valve at the property line, usually under a small round cap near the curb, and it is the water system's shutoff rather than the homeowner's. Most purveyors do not want anybody but their own people operating it, and an old one can break in the open position when it is forced, which turns a scheduled repair into an emergency. If the house needs to be isolated, use the main shutoff inside, normally where the service enters the building. If that valve will not hold, the water system can shut the curb stop when they come out.
In winter, depth is the whole story
New Jersey's plumbing subcode requires exterior water piping to sit below the recorded frost line with at least 42 inches of earth cover over the top of the pipe, a number the state wrote into a blank the model code leaves open (N.J.A.C. 5:23-3.15). A service installed to that depth does not freeze in a normal winter. The ones that freeze are the ones that were never that deep: a line run shallow under a driveway that gets plowed bare, a section that was raised around an obstacle, or an old run nobody has ever seen. That is why the 42 inch rule is worth knowing when somebody tells you the line froze and it will be fine next year.
When it turns into a dig
A service line that has failed does not get repaired at the symptom for long. Old copper pinholes in acidic soil, galvanized closes up from the inside, and polybutylene from the 1970s and 80s fails at the fittings. Which one you have changes the conversation, and copper versus poly in New Jersey covers how to tell.
When it is a replacement, the work is ours: open the two ends, bore under a driveway or a finished walk rather than cutting it where that is the better answer, coordinate the permit and the water system's inspection, and put the surface back. Most single family service replacements are a one to two day job. What it costs is published rather than quoted in private, on water service replacement.
Two things not to do while you wait. Do not dig looking for the leak yourself: a water service shares the ground with gas and electric, and 811 is free and required. And if the leak is on your side and the meter is measuring it, running the water to keep the line from freezing is a bill you will regret. If it is actively flooding, or the house has no water at all and nobody is answering, we answer the phone at night.