Leaking pipes inside or underneath the concrete of a house's floor or foundation are called 'slab leaks'. Common signs of this type of leak are:

• Moist, wet, or damp spots/stains on flooring or carpeting
• Water coming through the foundation
• Sudden settling of the foundation
• Low water pressure
• A noticable increase in your water bill

Slab leaks occur in a house’s incoming water line (or sometimes in the outgoing sanitary sewer line). Leaks in both lines can cause large amounts of damage to the foundation. Leaks in incoming water lines will continuously leak because of the continuous flow and pressure.

Common causes of slab leaks in incoming water lines are:

• Water chemistry: The pH of water can have dramatic affects on the pipe(s) it travels through.

• Shifting of the foundation: Because of poor design or installation, or a change in the moisture of the ground, shifting can pull pipes apart.

• Water pressure: Water pressure that is too high, possibly because the diameter of the pipes installed may be too small, will corrode copper pipe. Leaks will also form at points where pipes bend or change direction.

• Poor craftsmanship or workmanship: Inferior plumbing materials or improper installation can contribute to slab leaks. A “kinked line” (a piece of pipe with an imperfection) or a “nicked line” (nicked by a non-plumber workman) can become a slab leak.