Underground and Main Water Line Leak Detection

Underground water line leak detection checks the pipe between the meter and house, traces its route and marks the suspected break before digging begins.

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What an Underground Water Line Leak Is

Soggy ground when there has been no recent watering
Greener or faster-growing grass in a narrow line
Water pooling near the foundation
A water meter that never stops moving
Lower water pressure inside the house

Where the Line Runs and Where the Shut-off Is

The service line usually runs from the water meter to the point where it enters the house, with a curb shut-off near the meter and a house shut-off near the entry point.

Find the meter box near the edge of the property and look for the curb shut-off in or near that box. Do not force a buried valve or use a special key unless your water provider permits it. The house shut-off is usually near the place where the service line enters the building, such as a utility area, garage or crawlspace.

Knowing which valve you closed matters. Closing the house shut-off isolates indoor plumbing, but the water line between meter and house remains pressurized. Closing the permitted curb shut-off stops flow into that buried line before digging or repair begins.

How an Underground Leak Is Found Without Digging Up the Yard

An underground leak can be narrowed down with meter testing, line tracing and acoustic equipment before a repair area is excavated.

Confirm the leak with a meter test at the curb. Turn off every water-using fixture and appliance, record the reading, wait 30 minutes and read it again.
Close the house shut-off to isolate indoor plumbing from the yard line. Continued meter movement points to the line between the meter and house.
Use acoustic listening equipment along the buried run to identify leak noise transmitted through the pipe and soil.
Trace the water line from the meter toward the house so its route is measured rather than guessed.
Pressure test the run to confirm that the underground line is losing pressure.
Compare the findings and mark the suspected break before any digging starts.

What Underground Leak Detection Costs Depends On

Underground leak detection cost depends on the pipe depth, the surface above it, the length of the search and the repair approach.

Factor	Why it matters
Depth of the line	Deeper pipe runs can require more tracing and excavation planning.
Lawn, driveway or landscaping above the line	The surface affects access, restoration and the method used to reach the pipe.
Length of line to scan	A longer meter-to-house run requires more tracing and listening.
Coupling or re-route	A repair at one break and a replacement route require different work.
After-hours response	Urgent scheduling can affect the service cost.
Leak under a hard surface	Concrete or pavement can change how the leak is confirmed and accessed.

Review the main water leak detection cost factors before discussing the scope.

What to Do Right Now, and Who Owns the Line

Shut off the water at the house or at the permitted curb shut-off if you know how to operate it safely.
Take a meter reading before and after the water has remained off for 30 minutes.
Do not dig blindly because the route may cross other buried utilities.
Keep escaping water from spreading across driveways, concrete and other hard surfaces when it is safe to do so.

Frequently asked questions

How do I find a water leak between the meter and the house?

Turn off every fixture and appliance, then record the meter reading and check it again after 30 minutes. If the meter still moves after the house shut-off is closed, the buried service line is a likely source and should be traced and tested.

Where is my main water shut-off valve?

The house shut-off is commonly near the point where the service line enters the building. A curb shut-off may be inside or near the meter box. Ask your water provider before operating a valve that requires a special tool.

Can an underground leak be repaired without digging up the whole yard?

Yes, in many cases the line can be traced and the leak marked so excavation is limited to a specific area. The pipe condition, depth and surface above it determine whether a local repair or re-route is appropriate.

Is the line between the meter and the house my responsibility?

It usually is, because it is generally on the homeowner's side of the meter. Confirm the boundary with your water provider because the meter and shut-off arrangement can vary.

Why is my water bill still high after a leak was fixed?

The bill may include water used before the repair, or another leak may still be present. Check the current meter with all fixtures off and ask the water provider which usage period appears on the bill.