Signs of Hidden Water Damage in a Slab Home

Quick answer: The common signs of hidden water damage in a slab home are a water bill that jumps for no reason, a warm spot on the floor, musty smells, cupping or lifting flooring, swelling baseboards and stains that keep coming back. Do a meter test before assuming anything.

Why slab homes hide water

Most Moreno Valley houses are 1980s to 2000s tracts built on a concrete slab, with no basement and no crawl space. Water lines often run in or under the slab, and flooring goes straight on top. When something leaks, the water spreads under carpet, laminate or tile and wicks up the bottom of walls. You often see it last.

The signs

1. Water bill jumps with no change in use. Compare to the same month last year.
2. Meter moves with everything off. Turn off every fixture and watch the leak indicator on the meter for 15 minutes.
3. Warm spot on the floor. Usually a hot-water line leaking under the slab.
4. Musty smell in one room or one cabinet.
5. Flooring changes. Laminate cupping or peaking, tile grout cracking or darkening, carpet damp at the edge.
6. Baseboards swelling or paint bubbling at the bottom of walls.
7. Sound of running water when nothing is on.
8. Ceiling stains in summer under an attic AC; see AC condensate leak damage.
9. Sink base soft or stained from a slow drip.

The meter test

Shut off every fixture, including irrigation and the ice maker. Find the meter at the curb. EMWD serves most of Moreno Valley; part of western Edgemont is on Box Springs Mutual. Watch the small leak indicator dial. If it moves, water is going somewhere. Then close the main shutoff at the house. If the meter still moves, the leak is between the meter and the house. If it stops, the leak is inside.

Why it happens here

Hard water, often around 250 to 300 ppm, wears copper and fittings from the inside. Parts of the valley sit on expansive clay soil that swells and shrinks with moisture, which can stress lines in and under the slab. Older homes are more likely to have original copper in the slab.

What to do next

If the meter test points to a leak in the slab, call a leak-detection plumber. For wet flooring and walls, read slab leak water damage. If you've found mold, see mold remediation after water damage. Or call (555) 010-0000 and we'll help you sort out which comes first.