What Causes Pinhole Leak in Copper Pipe?

Pinhole Leak in Copper Pipe

Most homes today have copper plumbing pipes for the water supply of both hot and cold water. Copper pipes can develop tiny holes in them that start to drip water. This can cause damage to wood, sheetrock, anything below it, and lead to mildew growth. New construction makes use of plastic “PEX” pipe for the reasons we’re going to discuss below. 

It appears odd to find an article about leaking plumbing pipes on a site primarily discussing electrical systems. However, copper pipe corrosion can often stem from electrical issues, given copper’s conductivity and connection to the electrical system. Pinhole leaks in copper pipes may develop due to stray current from the home, utility, or a neighbor’s house. In this article, we’ll explore the development of such leaks.

I advise hiring a professional plumber and/or electrician for diagnosing pinhole leaks in copper piping. Deadly voltage could be traveling through the pipes, requiring careful handling.

Understanding Copper Pipe Leaks: Electrical Causes and Safety Precautions

The short version here is that a copper pipe leaks and you notice some type of water damage resulting. Hopefully this is nothing crazy!

The copper pipes in a home develop tiny pin holes causing water to seep out. Many times this is accompanied by green oxidation. Before the holes actually penetrate the copper wall, you may see green blotches appear on the exterior of the copper pipe. Usually the actual holes are so tiny that you can not see them. They often develop from the inside of the pipe out when it is due to an electrical issue.

There are more than one reason that pinhole leaks can develop. Acidic water, chemical reactions, hard/soft water, water turbulence, etc. can all cause pinhole leaks. What I want to address in this article is pinhole leaks due to stray electric current traveling on the copper water pipes.

NEVER touch a pipe that you suspect to have pinhole leaks as it can be carrying deadly electric current. At this point it is advisable to test for current in the pipe. A simple clamp style ammeter will do the job. ANY current, even .1A is cause for calling an electrician and/or your utility company. Take a look at this real life example from a job my company was on recently:

Amperage on pipe
6.5A on a water pipe, about 108X the lethal amount of amperage to kill a human!

Often, a plumber will be called to fix the pipe and the plumber notices a distinct arc (spark) when the pipe is cut for repair. At this point, the plumber will be able to identify that there is something more than mineral damage and advise an electrician to come test for stray current. An electrician will then test the water main ground and ground rod(s) for amperage. If amperage is found there are a few steps that must be taken to get to the root of the problem.

How Can It Be An Electrical Issue?

I know holes in a pipe sounds like a purely physical phenomenon but it can in fact occur due to an electric problem. Remember, electricity always wants to return to its source. If the return path of your home electrical system is impeded, by say a broken neutral conductor, the return path becomes the water piping system because it is bonded to your electrical system. 

In suburban settings, where pinhole leaks due to stray current are a common occurrence, most of the time it is due to something on the utility side. 

For example, if the neutral leg of one of the electric utility companies cables is compromised at your neighbor’s home, electricity will find the next best path to its source (NOT ground). That next best path to source could very well be the water main ground in your house, from the neighbors house, to your electrical panel to the source (utility). Remember, your electrical system is connected to your neighbors and everyone else on your system if you have metallic plumbing as most homes do. This is a big concern of folks who do EMF remediation where the concern becomes harmonics as well as potential stray current from an outside source.

Broken neutral at house connection
Broken neutral at house connection. NOT good!
Broken neutral at utility
Broken neutral at utility pole

What to do:

  1. When a copper pipe leaks, you need to first call a professional plumber. They need to be extremely careful when repairing the pipes because the pipes could be conducting a potentially lethal amount of electricity. It could be carrying the current from not only your home but multiple homes! Most professional plumbers will know exactly what to look for and recommend calling an electrician that specializes in this type of repair.
  2. Call your electric utility company. Explain that your copper pipe leaks and that you suspect it may be an electrical issue. As silly as it sounds they will know what you are talking about. This may save you a service call from an electrician if the problem is occurring outside of your home. Ideally they can verify the stray current, identify the reason for it, and correct it. This is extremely common.
  3. An electrician needs to test the current (amperage) flowing to the pipe and then check the neutrals in the electrical panel, at the utility connection of the home, and at the electrical meter. If your electrical panel is corroded or if there is a bad connection on the neutral/ground side you may have an isolated issue. In this case your electrician will make the necessary repairs and then you’ll get a plumber to repair the pipes.
  4. Repairs need to be made (electrician and/or utility, and plumber) and the amperage needs to be tested again on the water main ground and ground rod(s).
  5. If the problem persists, the utility needs to be called again until there is no remaining amperage on the water main ground.


Pinhole leaks are costly, annoying, and can be dangerous. They can be due to an electrical fault and you need to verify that there is no electrical issue when you’re dealing with pinhole leaks. I hope my article was able to explain how and why this can happen as well as the proper steps to take when dealing with this copper piping issue.
If you need a reputable electrician that can test and check your home for stray voltage, head on over to our National Electrical Registry and call a local professional that we trust. As always feel free to contact us with any questions. Thanks for reading.

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