A slab leak is a type of water leak that occurs beneath the concrete foundation (or slab) of a home when a water pipe breaks or leaks. These pipes are usually copper water lines running under the slab. Because the leak happens below the concrete foundation, it can be difficult to detect early and can cause significant damage if left unaddressed. Common causes of slab leaks include:

• Corrosion of pipes due to chemical reactions between the metal of the pipes and the soil or water.
• Abrasion, where pipes rub against the slab or other materials due to movement, leading to wear and leaks.
• Poor installation during construction resulting in weakened or improperly fitted pipes.
• Shifting soil or foundation movements, especially in areas with expansive clay soil that expands and contracts with moisture changes.
• High water pressure that stresses the pipes over time.

Slab leaks can lead to serious problems such as foundation cracks, water damage, mold growth, and high water bills. Because slab leaks are hidden under the foundation, signs to watch for include:

• Unexplained increase in water bills.
• Low water pressure in the home.
• Sounds of running water when no taps are on.
• Warm or wet spots on floors.
• Cracks in the foundation or walls.
• Musty or moldy odors near the foundation.

Detecting and repairing slab leaks early is important to prevent costly structural damage to the home. Repair options vary from rerouting pipes, tunneling beneath the slab, breaking through the slab, or trenchless repairs to fix leaks with minimal digging. In summary, a slab leak is a leak in the water pipes underneath a home's concrete slab foundation, caused by various factors such as corrosion, abrasion, soil movement, and poor installation, posing risks of structural and water damage if not addressed promptly. This explanation is based on multiple authoritative sources on slab leaks and their causes, signs, and repair methods.