Acidic Water
Blue-green stains on copper water pipe and fixtures indicate acidic water
Copper is the most common water service pipe material in most communities. Heavy, thick-walled, type K (look for the green stripe), copper pipe is usually used for service lines. It lasts many decades unless carrying “aggressive” water, buried in acidic soil, exposed to acid rain, or is in direct contact with concrete (where it passes through a foundation wall, it should be protected by anticorrosive tape or foam).
Copper pipe has a normal life of greater than 75 years. However acidic water can shorten the life of copper pipe. Water that is truly acidic (with a pH less than 6.2) can eat pinholes in the pipe and cause nerve damage due to copper poisoning. Acidic water can leach out lead from solder in copper joints installed before lead was banned in 1988 and cause lead poisoning. Blue-green stains around fixtures indicate the acidic water is eating away the interior of the copper plumbing. Some individuals with fixtures exhibiting this concern wait until pin holes develop in the pipe (and perhaps flood the house), then replace the plumbing system (replacement is highly recommended if lightweight type M copper pipes are old and have little remaining life). Other individuals install water treatment systems. The stains often can be removed with vinegar or lemon juice.
A water treatment system incorporating a chemical feed pump that adds a metered amount of soda ash to the water can bring the pH nearer the ideal of 6.8. An alternative is to add a tank with limestone in it. As the water flows over the stone, the stone will dissolve and, eventually, must be replaced. If the dissolved minerals make the water too “hard,” a water softener can be added.
Tape, caulk, automobile hoses, and other materials used for temporary repair of pipes or joints are not likely to last long. They should be replaced with materials that are approved for use in a plumbing system. Temporary repairs are a mark of amateur workmanship. If blue-green water stains are noted and temporary repairs were made, ask a plumber to thoroughly inspect the whole system to see if the amateur made other errors.
Chet Riley is the Owner/Proprietor of CENTENNIAL Home Inspections. For any questions regarding home inspections, please call Chet at 585-293-2278. Or e-mail him at criley1@rochester.rr.com. Further information can be obtained at http://www.centennialhomeinspections.com/.