Many homes built in the Southwestern United States in the mid-eighties were built with a concrete slab foundation and soft copper water pipes under the slab.
The codes require that soft, bendable copper be used because hard copper joints are not permitted beneath the slab.
Many unfortunate homeowners have experienced the effects of slab leaks underneath their home's foundation. The traditional remedy for a slab leak is to locate the leak, remove the flooring above the leak, jack hammer the concrete slab to expose the pipe, repair the leak, test the repair, repair the slab, and repair the flooring. The most common symptoms of a slab leak are those you can see, hear, or feel. Symptoms can include a warm spot on the floor, wet or flooded flooring, soggy or flooded landscaping, decreased shower or faucet water pressure, dirty or sandy water, persistent hissing heard at angle stop or under flooring.
The causes of slab leaks can be attributed to a number of possibilities. Before concrete slab foundations are poured, soft copper is laid in utility trenches according to design. Sometimes the soft copper can be kinked, over-bent, or dented. Also, the copper pipes may come into contact with other metallic materials which may cause galvanic reaction, an electric exchange between two dissimilar metals. Aggressive water chemistry is another factor that is gaining more attention as a cause of pipe failure. Essentially, the chemicals which are used to make public water safe to consume are also leading to an adverse electro-chemical reaction. These reactions can cause de-filming of the beneficial mineral lining in copper pipes and expose the bare copper piping and soldered joints to the aggressive water supply.