How to Repair an Underground Water Line

Underground Water Line - Broken

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A cracked or severed underground water line is a vexing problem that few homeowners ever want to face. Much like a broken sewer pipe, a broken underground water line appears that it might be an expensive, time-consuming project that upsets your entire life.

But it doesn't have to be that way. By separating this project into manageable steps, you can repair your underground water line by yourself, or at least take on some parts of it, thus reducing the project's overall cost. Repairing an underground water line is often less arduous than repairing a sewer line since the line is located closer to ground-level. Plus, the digging can be done by hand, eliminating the need for hiring an expensive compact excavator.

Safety Considerations

Prior to digging in your yard, you should always have utility lines marked by your local utility location service. Typically a free service, a technician will mark your yard with paint indicating blue for potable water lines, red for electrical cables, green for sewer pipes, and orange for gas, oil, and steam. Call 8-1-1 for scheduling. Also, you should consult with your local permitting office for information about zoning and permits. Check your home's title documents or your county website's tax assessor section for any information about easements that may run through your yard.

Project Metrics

  • Working/Total Time: 1 to 2 days
  • Skill Level: Intermediate
  • Material Cost: $25 to $75

What You'll Need

Equipment/Tools

  • Shovel
  • Spade
  • Tarp
  • Hammer
  • Adjustable wrench and screwdriver
  • Dedicated water/gas shut-off tool (optional)
  • Bucket
  • Shop vacuum

Materials

  • Replacement water line service pipe (usually 1-inch diameter)
  • Twine or string
  • Wood stakes

Instructions

  1. Determine If You Have a Leak

    Some common indicators of a leak in your underground water line include:

    • Unexplained increase in municipal water bills
    • Water meter indicator is spinning even though no water in or around the house is turned on
    • Mushy, soft spots in yard
    • Recessed or swelling lawn or ground
    • Low water pressure from faucets or showerheads in the house
  2. Locate the Leak

    Once you know the general area of the leak, pinpoint its precise location. One way to do this is by running a sightline from your home's street-side water meter to the point where the water enters your home. Drive a stake close to the water meter and another stake near the point where potable water enters your home. Run a taut twine or string from stake to stake.

  3. Turn Off Water to the House and at the Street

    Find the water shut-off valve for your house and shut it off. Open the metal water meter box. Locate the valve beside the meter, on the house side of the meter (not the street side). Carefully turn it clockwise. It is preferable to use a dedicated water/gas shut-off tool. If you do not have one, you can fit an adjustable wrench over the valve and turn the wrench with a screwdriver inserted into the back off the wrench.

  4. Dig the Trench

    Spread out the tarp next to the suspected area of the leak. Your twine or string should indicate one axis; the heaviest concentration of water in the soil should provide the second axis. Remove the twine. Place the sod and dirt on top of the tarp. If you wish to reuse the sod, carefully cut it out with a spade and place it to the side in a separate area. Unlike sewer lines, which can run several feet below ground-level, water service lines typically are located just below your area's freeze line: from 1 foot to 3 feet below ground-level.

  5. Drain Water From the Trench

    Bail water from the trench with a bucket. Toward the end, drain the rest of the water with a shop vacuum on wet mode.

  6. Repair the Water Line

    Depending on the age of your home and any subsequent modifications, your underground water line may be copper, PVC, galvanized steel, CPVC, or PEX. Replace the line with similar materials. Typically, this pipe will be 1-inch in diameter. Most codes specify that an underground water line should be no less than 3/4-inch in diameter and that it be separated from any waste or sewer lines by no less than 5 feet of undisturbed or compacted soil.

  7. Test the Repair

    Turn on the water at the meter by turning the nut counter-clockwise. It is not necessary to turn on the water into your house yet. Examine your repair under pressure to make certain that it is secure. If permitting the work, leave the trench open until inspection.

  8. Fill the Trench

When you are satisfied with the repair, fill in the trench with the soil. At the end, replace the sod by hand, if applicable. Turn on water into the house again.

When to Call a Professional

Repairing an underground water line is a time-sensitive project: Until the line is repaired, your home will have either little or no fresh water. If you are not confident about your ability to turn the project around in a satisfactory period of time, you'll need to call in a plumber. Generally, a plumber can fix a single-leak underground water line within a few hours.