Pinhole leaks in copper pipes
Q. I am a Realtor and have noticed a chronic plumbing problem in one of the subdivisions in my area. Many of the homes in the neighborhood have developed pinhole leaks in the copper water pipes under the slab floors.
Obviously, this is very expensive to fix and can cause serious damage. What could be the cause of this problem: materials, workmanship or what?
A. Copper piping became the standard for homes in the late 1960s. Unfortunately, as these systems are aging, pinhole leaks are becoming more common, but not always for the same reason.
Copper pipes are manufactured in various gauges. That is, some have thicker or thinner walls than others. Years of water flow can gradually erode the interior surfaces of these pipes so that the thinner gauge systems eventually wear through and begin to leak at tiny penetrations. Many contractors, in order to be competitive, used the minimum required gauge of piping, and these are where leaks are most likely to develop. Additionally, some imported copper piping was of compromised quality.
Another cause of copper pipe leakage is electrolysis. This is most commonly caused by contact with steel piping, but it can be caused also by contact with some types of soil. Electrolysis causes internal corrosion of the pipes, resulting in pinhole leaks.
A third cause of pinhole leaks, less commonly known, involves hot water circulation pumps that run continually. Minerals and microscopic air bubbles in the water can act as abrasives against the interior surfaces of the pipes and cause leaks at the elbow joints.
To determine which of these causes is affecting the neighborhood in your area, a comprehensive evaluation by an experienced, licensed plumber is advised. This will help to determine whether the water supply systems can be repaired or should be replaced. An optional means of repair is to have the interior surfaces of the pipes coated with epoxy.
Q. We have an old gas heater in our small bathroom. It seems to leak when it's lighted, so we want to replace it. What can we legally install in its place? We don't have adequate wiring for an electric heater there, and besides, we want a heat source that continues when the power goes out.
A. Your home must be very old because gas heaters in bathrooms have been illegal for many years. The reason for the prohibition is to prevent people from losing consciousness in a bathtub due to lack of oxygen. Gas combustion can consume the air supply and in some cases can allow exhaust to vent into the room. Until you replace this fixture, you should curtail its use until it has been professionally evaluated by a licensed HVAC contractor or the gas company.
As to replacement: Electric space heaters are common, reliable and safe in bathrooms. Unless you have frequent power outages in your area, an electric heater would be a good choice. Some bathroom heaters can work on the same circuit as a light fixture. A heating contractor can advise you on available products.
• To write to Barry Stone, visit him on the web at www.housedetective.com, or write AMG, 1776 Jami Lee Court, Suite 218, San Luis Obispo, CA 94301.
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