Slab Leak Repair

Signs of a Slab Leak

Slab leaks are hidden under concrete, so you find them by their side effects. A warm patch on the floor usually means a hot water line; an unexplained spike in the water bill or a meter that moves with everything off can mean either line.

• Warm spots on the floor
• The sound of running water when nothing is on
• A water meter that moves with all fixtures off
• Damp carpet or warped flooring
• New cracks in the floor or foundation

Is the Leak on the Hot or Cold Line?

With every fixture off and the water meter still moving, close the cold water inlet valve on top of the water heater. If the meter stops, the leak is on the hot water side, which is the most common slab leak and the one that warms the floor. If the meter keeps moving, the leak is on the cold side. Telling the plumber which one you found shortens the locating time. For a broader overview, see leak detection and repair.

How Slab Leaks Are Found and Fixed

The plumber first confirms the leak and works out whether it's on the hot or cold side, then pinpoints it with acoustic and thermal equipment. From there it's a choice between breaking the slab for a spot repair or rerouting the line around it.

1. Confirm the leak and whether it's on the hot or cold side.
2. Pinpoint the location with acoustic and thermal equipment.
3. Decide between a spot repair, a reroute or a repipe.
4. Make the repair and pressure test the system.

What Affects the Cost of Slab Leak Repair

Most of the cost comes from locating the leak precisely and the repair method you choose.

• Locating the leak precisely under the concrete.
• Repair method: breaking the slab for a spot repair, or rerouting the line.
• Flooring removal and replacement over the leak.
• Whether more than one line is leaking.

When a Slab Leak Needs Immediate Attention

• Water is surfacing through the floor.
• A hot water line is leaking and the floor is warm; close the cold inlet to the water heater.

Clay Soil and Slab Leaks in Texas Cities

In Houston, Dallas, Fort Worth and San Antonio, most homes sit on slabs over clay soil that swells and shrinks with moisture. That movement stresses the lines under the slab, so slab leaks are more common here than in cities with basements. Rerouting the line is often the better choice when the home's original piping is aging.

Local plumbing details: Houston, Dallas, Fort Worth, San Antonio

Slab Leaks by City

What our city pages say about slab leaks:

• Upland, CA: Copper under older slabs pinholes with age.
• Rowlett, TX: Clay soil swells and shrinks, stressing water lines under the slab.
• Avondale, AZ: Lines under the slab leak unseen until a floor is warm or the bill jumps.
• Pinellas Park, FL: Copper lines under the slab pinhole and leak unseen.
• Las Vegas, NV: Most homes sit on concrete slabs, and leaks in the lines beneath them show up as warm floors or high water bills.
• Foley, AL: Lines under the slab leak unseen until a floor is warm or the bill jumps.
• St. George, UT: Lines under the slab leak unseen until a floor is warm or the bill jumps.
• Lawton, OK: Clay soil swells and shrinks, stressing water lines under the slab.

Before the Plumber Arrives

• Recent water bills.
• Where the floor feels warm or damp.

Other Leak Detection & Repair Services

• Water Service Line Repair

Slab Leak Questions