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Fix a main water line that leaks

We'll help you shut off the water, check the meter, and know when to call a plumber for repair.

Troubleshooting · Home plumbing
15–30 min
What you'll need
  • None (plumber handles repair)
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Steps

Goal: Shut off the water, check the meter, and know when to call a plumber.

  • Shut off the main valve immediately to stop the leak.
  • Check the water meter with all fixtures off. If it runs, you have a leak.
  • Good: Meter is still—no leak or leak is elsewhere. Bad: Meter runs—call a plumber.

Shut off water

Goal: Stop the leak immediately.

  • Turn off the main shutoff valve. This stops water flow and prevents further damage.
  • Good: Water stopped. Bad: Valve does not close—call a plumber or water utility.

Check meter

Goal: Confirm a leak and determine which side.

  • With all fixtures off, watch the meter. If it moves, there is a leak.
  • Shut off the house valve. If the meter stops, the leak is on your side. If it keeps running, the leak may be on the utility side.
  • Good: You know the leak location. Bad: Call a plumber to locate and repair.

When to get help

Call a plumber if:

  • The meter runs with all fixtures off.
  • You see a soggy spot or water surfacing.
  • Pressure is low.

Call 811 before any digging.

Verification

  • Main valve is off until the leak is repaired.
  • Meter does not run when fixtures are off (after repair).

Escalation ladder

Work from the device outward. Stop when the problem is fixed.

  1. Shut off water Turn off the main valve to stop the leak.
  2. Check meter Confirm the meter runs with all fixtures off.
  3. Locate leak Check for soggy spots; do not dig without 811.
  4. Call a plumber Leak located or suspected—call a plumber for repair. Call 811 before digging.

What to capture if you need help

Before calling support or posting for help, have these ready. It speeds everything up.

  • Meter reading with fixtures off
  • Which side of meter (utility vs. your side)
  • Visible signs of leak
  • Steps already tried

Does the water meter run when all fixtures are off?

A running meter with no water use indicates a leak.

Shut off all fixtures. Check the water meter. Running: leak somewhere—shut off main valve, call a plumber. Not running: leak may be intermittent or at a fixture; check fixtures. For main line, assume leak and call a plumber to locate.

Yes No

You can change your answer later.

No main line leak detected

Meter is still with fixtures off. If you still see a leak or soggy spot, call a plumber to investigate. Leaks can be intermittent.

Done

Call a plumber

Call a plumber to locate and repair the main line leak. Shut off the main valve until repaired. Call 811 before any digging. Do not dig without utility markings.

Done

Reviewed by Blackbox Atlas

Frequently asked questions

Why would the main water line leak?
Common causes: corrosion, freezing and thawing, shifting soil, tree roots, or age. Main lines are under pressure and buried; leaks often show as soggy spots, low pressure, or a running meter with all fixtures off.
Can I fix a main water line leak myself?
You can shut off the water and check the meter. Locating and repairing an underground leak usually requires a plumber with leak detection equipment. Do not dig without calling 811 to mark utilities.
When should I call a plumber for a main line leak?
Call a plumber if: the meter runs with all fixtures off, you see a soggy spot or water surfacing, or pressure is low. A plumber can locate the leak and repair or replace the line. Call 811 before any digging.

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