Slab Leak Detection in Pomona, CA

Why slab leaks are common in Pomona

A big share of Pomona's houses are 1950s and 1960s tract homes built on concrete slabs, with the copper water lines laid in the ground under the floor. After 60 or 70 years, those lines wear out. The usual reasons:

• Abrasion. The pipe rubs against gravel, concrete or rebar as it expands and contracts. Hot water lines move the most, which is why so many slab leaks are on the hot side.
• Age. Decades of water moving through copper wear it from the inside, especially at bends.
• How it was installed. Lines that were kinked, nicked or pinched when the slab was poured.
• Ground movement under the slab over the years.

Once one under-slab line fails, other pipe the same age often isn't far behind. That's worth keeping in mind when you choose how to fix the first one.

Signs of a slab leak

• A water bill that's higher than usual with no change in how you use water.
• A warm or hot spot on the floor, often a sign of a leak on a hot water line.
• The sound of running water with every fixture off.
• A water heater that seems to run all the time.
• Damp or warped flooring, a wet carpet pad, or a mildew smell with no obvious source.
• New cracks in tile, or wet baseboards.
• A drop in water pressure.

Check your water meter first

You can find out whether water is leaking somewhere in about 15 minutes, before you call anyone.

1. Turn off every faucet, the shower, the dishwasher and the washing machine. Make sure no toilet is running.
2. Find your water meter. In most Pomona neighborhoods it's in a concrete box near the curb. The lid can be heavy, so pry it up with a screwdriver, not your fingers.
3. Look for the leak indicator on the meter face, usually a small red or black triangle or star. If it's turning with everything off, water is going somewhere.
4. Shut off the main valve at the house. If the indicator stops, the leak is inside the house. If it keeps turning, the leak may be in the line between the meter and the house.
5. Open the main again, then close the cold water valve on top of the water heater. If the indicator stops now, the leak is probably on a hot water line.

Not every leak is under the slab. Leaks inside walls, at irrigation lines, and on the service line from the meter show up on the meter too, and leak detection covers those as well.

How a slab leak is found

• Isolating and pressure-testing. Separating the hot and cold systems, and sometimes individual lines, to see which one loses pressure.
• Acoustic listening. Ground microphones pick up the hiss of water escaping under concrete.
• Thermal imaging. A hot water leak shows up as a warm pattern on the floor.
• Line tracing. An electronic locator maps where the pipe runs under the slab, so the leak can be matched to the pipe route.

The point is to narrow the leak down closely enough that, if the slab does have to be opened, it's a small hole in the right place.

Repair options

Spot repair through the slab

Break through the concrete at the leak, repair the pipe, and patch the slab. This works best when the leak is in an easy spot and the rest of the line is in good shape. It's harder to justify under hardwood, tile you can't match, or cabinets.

Reroute

Abandon the leaking line under the slab and run a new one through the attic and walls. No jackhammering through floors, and that run can't leak under the slab again. It does mean some drywall openings.

Repipe

If there have been several leaks, or the house still has galvanized pipe elsewhere, replacing the whole system may be the better use of money. See repiping.