By Barry Stone
Dear Barry,
Our home is 10 years old. When we bought it, the sellers disclosed that a leaking water line below the slab floor had just been repaired. We called the plumber who did the repair and he said there was no evidence of further problems. With this assurance, we bought the home. But a month later, another leak developed under the slab. The plumber open the floor and this time found numerous pinhole leaks. He advised us to re-pipe the house. We called the builder, but he said the pipes were installed to code, in a protective layer of sand, and he was not liable. Finally, our homeowner's insurance and home buyer's warranty refused to pay. What could have caused these pipes to deteriorate in only one decade, and how can no one be liable for this condition? - Dinah
Dear Dinah,
Copper water piping is generally resistant to corrosion, but there are two conditions that can override this positive quality:
1) Direct contact between copper and galvanized steel pipe can cause electrolysis, a natural interaction of dissimilar metals that promotes corrosion. To prevent this, dielectric fittings are needed wherever dissimilar metals are adjoined.
2) Some types of soil have unique chemistries that are corrosive to copper piping. In areas with such soil, approved plastic piping has been an acceptable solution.
As to liability for the current state of deterioration, no one truly appears to be at fault. The contractor has said that he set the piping in a protective layer of sand, as required. The plumber who repaired the first leak apparently found no other deterioration, and further evaluation would have involved breaking more of the slab. As for the insurance companies, homeowner's policies cover damage cause by leakage, but not the leaking itself. And home buyer's warranties do not cover preexisting conditions.
Unfortunately, you were on the receiving end of this unforeseeable problem, and it doesn't seem that anyone can truly be blamed.
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