A slab leak is a leak in the plumbing pipes embedded beneath or within the concrete foundation of a building. This guide covers everything you need to know.
What causes slab leaks?
Copper pipe corrosion from concrete chemistry (most common), shifting foundations, improper installation during construction, age-related deterioration (30+ year old pipes), and aggressive soil conditions. Copper pipes react with concrete over time — microscopic pinholes develop and grow.
Signs of a slab leak
Warm spots on floor (hot water), high water bills, musty smells, carpet staining, cracked tiles, sound of running water when no fixtures on, foundation settling, and consistently running sump pump.
Detection methods
Thermal imaging finds temperature differentials from hot water. GPR maps the in-slab plumbing layout. Acoustic correlation confirms the pressurized leak sound. Combined approach locates within inches — repair crew opens only 200-300mm patch.
Repair options
Pinpoint patch (small access hole, repair pipe, patch concrete) — cheapest and least invasive. Re-pipe (abandon in-slab pipes, run new pipes in ceiling or walls) — more expensive but permanent solution. Trenchless re-pipe (pull new pipe through old pipe) — option for some situations.
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