Slab Leak Repair in La Palma, CA

What a slab leak is

A slab leak is a leak in a water line that runs under or through the concrete foundation of the house. It's not a crack in the concrete. It's the pipe inside or beneath it. Because the water has nowhere obvious to go, slab leaks can run for weeks before anyone notices, soaking the soil, damaging flooring and wasting a lot of water.

They're a big deal in La Palma because almost every house in the city is a slab home. When the tracts went up in the 1960s and 70s, builders commonly ran copper water lines under the slab, and those pipes are now 50 to 60 years old.

Signs of a slab leak

• A warm or hot spot on tile, wood or carpet. Very common with hot water lines.
• The sound of running water under the floor when nothing is on
• A water bill that climbs month after month
• Damp carpet or warped wood flooring with no obvious source
• Cracks appearing in tile or the slab as soil underneath shifts
• Mildew smells or mold along baseboards
• A water heater that never seems to stop running
• Low water pressure throughout the house

If you suspect a slab leak, start with the meter test on our leak detection page. If the meter moves with everything off and the main valve open, but stops when the house valve is closed, the leak is somewhere inside the house, and under the slab is a strong possibility.

Why slab leaks happen

• Age. Copper lines installed decades ago thin out and develop pinholes.
• Water chemistry. Southern California's hard water, and changes in water treatment over the years, affect how copper wears inside.
• Abrasion. Pipes that expand and contract against concrete, gravel or rebar can wear through over time, especially hot water lines.
• Soil movement. Clay soils that swell and shrink with moisture, plus the occasional earthquake, put stress on pipes under the slab.
• Original installation. Kinks, poor joints or nicked pipe from construction can fail decades later.

How slab leaks are found

The goal is to find the leak precisely before any concrete is touched. Plumbers typically isolate the leaking line with pressure tests, then pinpoint the spot using acoustic listening equipment and thermal imaging. A precise location means a smaller repair and less disruption to the house.

Repair options

There are three common approaches, and the right one depends on where the leak is, the condition of the rest of the pipes and what's on top of the slab:

• Direct (spot) repair. The plumber opens the floor right at the leak, repairs that section of pipe and the floor is patched. This makes sense when the leak is in an accessible spot and the rest of the pipe is in good shape.
• Reroute. Instead of digging through the slab, the leaking line is abandoned and a new line is run through the walls or attic. This avoids breaking concrete and is often preferred when the pipes are old.
• Repipe. If the house has had more than one slab leak, or the copper is failing in several places, replacing the plumbing may be the more permanent fix. See repiping.

Ask the plumber to walk you through why they recommend one option over another, and what's involved in each, including any drywall or flooring work afterwards.

What to do while you wait

• If it's the hot water line, close the cold-water supply valve on top of the water heater to stop hot water flowing to the leak.
• If you can't tell which line it is, shut the main valve when you're not using water.
• Pull back any wet carpet and run fans to start drying the area.
• Photograph the affected areas and keep your water bills.

One leak, or the first of several?

Many La Palma homeowners find that once one slab leak shows up, another follows within a few years, because the pipes are the same age and have been through the same conditions. That's worth keeping in mind when choosing between a spot repair and a reroute. Our post on pinhole leaks in La Palma homes explains why.