How slab leaks develop
Under-slab supply lines fail through corrosion, abrasion against the concrete, shifting soils, and age. In British Columbia, soft or settling soils — the Fraser delta silt under Richmond and Delta, the clay benches around Kamloops — add stress that can open a joint or crack a line over time.
Hot-water slab leaks are especially common and especially telling, because the escaping warm water often produces a detectable warm spot on the floor above.
The signs of a slab leak
Watch for a warm or damp patch on the floor, the sound of running water with no fixture on, an unexplained jump in the water bill, low pressure, or cracking that appears as moisture undermines the slab. On BC's high-water-table ground, slab moisture can compound quickly.
Locating a slab leak without breaking the floor
Slab leaks sit where they cannot be seen or reached by inspection. Technicians use acoustic equipment to hear the pressurized water beneath the concrete, pressure testing to confirm the leak and isolate the line, and ground-penetrating radar to map what's embedded in the slab before any access is made.
Used together, these methods pinpoint the leak so that a single, small opening reaches it — protecting the foundation from unnecessary exploratory work.