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Q. We have been in our condo now going on eleven years. Since that time we have had five bursting holes in the three quarter inch copper piping in the ceiling. We have spent over a thousand dollars on repairs. Now our plumbing company is proposing to replace all of our hot water piping at a total cost of over three thousand dollars. Any ideas as to why these pipes are failing?
A. You are experiencing a problem that homeowners have been experiencing all over the country since around the early 1990s. Pinhole leaks certainly occurred before then but all of a sudden it seemed to be a near epidemic. All sorts of theories abounded that ranged from bad copper, poor installation, loose electrical grounding, bacteria or combinations of the above.
There are three thicknesses of common copper water piping and they are described as Type K, L and M. Type K is the thickest and I never see it in residential construction while the next intermediate thickness is Type L and that is used in houses on well water because we know well water is aggressive towards copper if untreated. Type M is used in houses with municipal water supplies and it is the thinnest. When people tell me that they are getting pinholes and still want to use copper for the repair I tell them to go to Type L pipe.
The odd thing is that you can have a pipe with lots of pinholes in it right next to a section with none. There appears to be no certain predictor of which pipe is going to spring a pin hole leak and which isn’t. The city of Jacksonville Florida became so frustrated with the problem that they tried to ban copper from new construction in their area.
What most researchers suspected is the conditions that produce the problem are presented by the 1991 phased-in amendments of the 1974 Safe Drinking Water Act. Dr. Marc Edwards of Virginia Tech worked for over a decade trying to scientifically replicate the conditions that produce pinhole leaks in the lab and in about 2003 he finally did it.
Dr. Edwards says, “One pinhole leak in a home isn't so bad but once you have two, plumbers and insurers usually recommend replacing the plumbing, figuring that other leaks are bound to happen. That's typically a $2,000 to $6,000 investment. If those leaks cause mold problems inside the walls, the home's resale value could plummet. The problem was that no one wanted to take responsibility for the problem. Homeowners were basically left to fend for themselves.”
There is a company that sells a system that coats the inside of the pipe with an epoxy to stop pinhole formation without ripping walls and ceilings out and replacing the pipe. It’s called epipe® (www.aceduraflo.com). I don’t know its availability around here but there is a market for it.
Replacement options run the gamut from replacing the old copper with new, and as I mentioned, I recommend up-sizing the pipe thickness. CPVC plastic is good and cross-linked polyethylene, or PEX as it’s called, a pipe recently accepted here for potable water supply systems, has had a long successful history in Europe and I think such products are the future of domestic water pipe.