Contrary to popular belief copper water piping doesn't last forever. In its original design criteria, copper piping was projected to last for 20-25 years, but failure can often occur in as little as two years due to water chemistry.
Changes in water chemistry, unrelated to water quality, have caused the water to become aggressive towards the copper piping.
Copper is the most widely used material for plumbing systems because of its ease of use, resistance to corrosion, and resistance to permeation by liquids and gases, which may be sources of corrosion and contamination.
Copper piping has been used for domestic water supply for over 50 years. Since 1963, over 5.3 million miles of copper plumbing tube has been installed in about 80 percent of all U.S. buildings.
Hot or warm spots in the floor, soaked carpeting, ceilings or walls and abnormally high water bills are signs of failing copper pipes.
Pinhole Leaks The State of Cajifornia Task Force to Study Pinhole Leaks in Copper Plumbing defines a copper pinhole leak as "the perforation of copper tube, pipe or fittings used for domestic water distribution as the result of pitting corrosion initiated on the interior/waterside surface with the subsequent leakage of water."
Internal pitting corrosion of copper pipes is a rare but costly problem that leads to the formation of pinhole leaks. Although the factors that cause this problem are mostly unknown, it is well recognized that the chemistry of the water traveling through the pipes can influence the formation and propagation of pits.
A pinhole leak is a final breakthrough event of the progressive attack of pitting corrosion on copper water plumbing. A copper water plumbing system can be in a condition of having significant damage by pitting corrosion, but not have pinhole leaks. The challenge is how to discover pitting corrosion before pinhole leaks develop.
Although pinhole leaks could happen in any copper pipe or tube within a house, the Washington Suburban Sanitary Commission (WSSC) reported that the majority of pinhole leaks that their customers had reported were in cold-water, horizontal copper piping. Most of the leaks were in older homes, and 80 percent of the reports involved homes built prior to 1970.