Pinhole Leaks in Copper Pipes

I inspect many condominiums and large buildings here in Vancouver. Often the inspection of the boiler room will reveal failure of the copper pipes, in the form of corrosion and pinhole leaks. This recent condo inspection turned up leakage on the hot water supply piping for the building:

A failing hot water pipe in a mechanical room

Corrosion like this may indicate a chronic problem throughout the building’s plumbing lines. Pinhole leaks are unfortunately a common occurrence for many homeowners, and, from my experience, there is a lot of misinformation regarding this problem.

What is a pinhole leak?

Cross section of a leaking pipe

A pinhole leak is the breakthrough of the pipe wall when the pipe is undergoing “pitting corrosion” or simply “pitting”. When enough pitting occurs in the interior of the pipe, it will break through and water will begin to travel to the exterior of the pipe.

What causes pinhole leaks?

Corrosion in the boiler room of a condo building.

Pitting corrosion (pinholes) are directly related to water chemistry. High or low pH balance and water softness/hardness (high/low mineral content of the water) will directly affect certain types of copper piping, and can cause accelerated corrosion. Vancouver, for example, has extremely soft water.  The low mineral content has been blamed for poor protection from corrosion. For instance, in a hard-water region, the minerals in the water will form a protective layer on the interior of the pipe. Vancouver therefore suffers from greatly reduced copper lifespans.

What kinds of pipe are affected?

Hot water and heating supply lines are statistically more frequently damaged by pinhole leaks. The high temperature of the water can accelerate corrosion. Certain types of pitting will not occur in low water temperatures.

TIP: If you are inspecting a home or condominium, always have a look at the hot water lines near boilers/hot water tanks. Typically the hot water lines will fail before the cold lines.

What are the solutions?

Although there are several fixes for failed piping, the most obvious solution is to re-pipe the building. However, this is also the most expensive and destructive of the options. With the advent of flexible, easy-to-install PEX (Plastic piping), it is easier and more cost-effective than replacing with new copper lines, however significant damage to the interior walls is still often necessary.

Epoxy coating is a newer method that coats the interior walls of the pipe with a sealant. The system is shut down, water drained, and the coating pumped in. The advantage to this system is the lower downtime needed VS replacing the pipes. It is also less costly than re-piping.

UPDATE: After posting this article, I was contacted by Randy at CuraFlo BC, a company that specializes in epoxy coating. He answered several questions about epoxy lining, including addressing the common perception that the epoxy linings will fail prematurely. According to CuraFlo, there was some faulty product used prior to 2004, however their newest lining material, “CuraPoxy” has an extremely long service life up to 50 years. I will be providing more information on this system in a future blog post. Thanks Randy!

A chemical water treatment system.

Water treatment is the lowest-cost option. A chemical injector is installed on the water lines which injects a corrosion-inhibitor into the water as it passes through. This is a popular option for large buildings where re-piping would be extremely costly. Although it will not repair existing holes, the companies selling these products claim it will stop further corrosion from occurring. The downside to this system is the ongoing cost for injector and chemicals. It is also unclear whether these systems are a reasonable long-term solution.

One company offering water treatment in Vancouver is Hytec Water Management. I see many of these systems installed and strata owners seem to be happy with their performance.

What else can I do?

One word of advice: NEVER drain a copper pipe suffering from pinhole leaks. Draining and re-pressurizing a copper pipe may cause debris / mineral deposits sitting in pitted areas to loosen and cause a multitude of new leaks.

Further Information

For more information on this subject, visit the EPA website at http://www.epa.gov/sciencematters/april2011/leaks.htm

CuraFlo BC – CuraFlo BC