Copper piping provides a relatively reliable material under most conditions due to the formation
of a protective layer of cuprous oxide that protects it in most environments. However, a recent
series of failures of underground copper water supply pipes have been reported near Miami,
Florida. All of these failures involve type L copper pipe located under concrete slab-on-grade
foundations in a single sub-division. All of the copper plumbing under the slab is encased in a
continuous plastic sleeve as required by the state building code. The rationale for the sleeve is
to protect the sub-slab copper pipe from aggressive soils, groundwater, and concrete leachate.
One builder last reported failures in 20 homes, some of which incurred multiple failures. The
plumber who installed the copper supply pipes indicated that a second builder is facing similar
problems, although these could not be confirmed. This report contains results of a preliminary
investigation of failed plumbing materials retrieved from two homes.
National Association of Home Builders