My Lg Washing machine is leaking electrical current into my copper water lines when idle. 16v from the cold water line and 3v from the hot line. After purchasing this washing machine, I began to notice new corrosion on my pipes in my basement, in cabinets, and elsewhere in my house.

Could this electrical leak be causing the corrosion? AC current is leaking, not DC. I believe DC is required for electrolysis to occur, but I'm not sure. If AC current in water can create excessive oxygen and hydrogen, and excessive oxygen speeds up corrosion in many metals; perhaps this will corrode copper quickly as well.

This seems to me like my washing machine has faulty solenoid valves or something in it. Is this actually normal? Related pictures below.

16v from the cold line: Voltage from the cold line

3v from the hot line: Voltage from the hot line

.8v when machine freshly unplugged: .8v when machine freshly unplugged

A couple areas with the blue/green stuff I'm calling corrosion:

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    @manassehkatz-Moving2Codidact ah, good point. I do have a ground fault, I think. It is what led me to post this question. I'm not yet sure how significant, I suppose I'll measure the current tomorrow to see. I called it a leak, not knowing the term "ground fault". Thanks!
    – zerpsed
    Commented Jan 2, 2022 at 4:15
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    New laundry rooms are required to have GFCI protection on receptacles. I would retrofit that, and see what happens. GFCI protection can be placed at the receptacle (the thing you're most familiar with), or be fed from a receptacle or deadfront closer to the panel (a deadfront has no sockets), or be at the breaker. Commented Jan 2, 2022 at 4:50

3 Answers 3


I am much more concerned about whether you have a ground fault or not. If you have electricity actually "leaking" then you have a life safety problem that is far more important than long-term pipe corrosion. The ideal (required by newer code) setup is to have GFCI protection for washing machines. Your receptacle does not have GFCI, but you might have it in the electrical panel. If you do, great. If not, that is what you need to figure out first.

There are times when there is "phantom voltage" detected by a multimeter. That is quite common when checking voltage on wires connected to a currently "off" device. But any time you are dealing with water and electricity, you really need to get to the bottom of it. One definitive solution is to replace the regular receptacle with a GFCI receptacle. If you install it correctly (there are some possible "gotchas", particularly if there are other things on the same circuit) and it works fine but when you plug in the washing machine it trips then you know you have a real ground fault. If it doesn't trip then you are likely detecting "phantom voltage" at such a low level of current that it is simply not a concern. Figuring this out without installing a GFCI gets a bit more complicated.

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    Thanks, I was too curious to wait until tomorrow to check the current. It is a tiny but steady 1.9 micro amps, consistently at 16v; quite insignificant and sounds like what you describe as phantom voltage. I will install a GFCI outlet in my laundry room sometime soon for safety and to monitor for significant leakage.
    – zerpsed
    Commented Jan 2, 2022 at 4:35
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    microamps is fine. milliamps is where it becomes a problem. Typical GFCI (according to Google...) trips in the 4 - 6 milliamp range. 1.9 microamps is likely not an actual "leak" but just induced somewhere along the way. Commented Jan 2, 2022 at 4:42

Yeah, that looks like galvanic corrosion all right.

If you have the route for a wire, I would bond the pipes in question to the house's Grounding Electrode Conductor. That will arrest any galvanic corrosion (by giving it a much better current path) and with luck, that better current path will result in the ground fault becoming more feisty, leading to a breaker trip.

I would also carefully review the circuit grounding from panel to washing machine.

I would also review the Grounding Electrode Conductor system from the panel to the ground rods, Ufer ground or metal water main bond. Happens all the time where a house gets a plastic meter, or repairs with plastic pipe, and nobody realizes they've interrupted the GEC system. Then you get lots of weird currents lots of places.

Note the current on the GEC system isn't necessarily your current. If it's still there when you trip your main breaker, then a neighbor has a lost neutral and their neutral current is seeking back to the transformer via the dirt and everyone else's GEC.


A current of a few micro Ampere won't start that much corrosion over a period of only a few years.

It is most important to avoid any loop in the grounding system. I.e. a star configuration is necessary to connect ground, neutral, metal tubes, metal conduit, metal bath tubs etc. at only 1 location, often close to the metering place.

Otherwise it is more likely that a part of the grounding system has more current then only a few micro Ampere.

And multiple grounding is like a big loop that will catch every 120/230V A/C field nearby which may result in problems with electronics as well: hum in stereos, computer problems, problems with routers, smart home devices etc.

The green corrosion at the 90 degree bow looks like a weak solder connection, perhaps the acidic solder paste was not removed and/or a flushing/cleaning was not done.

And the most important rule with metal tubing should be checked: Only equal or more noble metals in flow direction must be installed. F.e., tinned steel tubes upstream of copper tubes is ok. But if steel tubes are installed downstream of copper tubes, some copper parts may flow to the steel tubes and could cause local pit corrosion. This kind of corrosion can't be compensated via a sacrificing anode or an injected current via long life anode, since it is only a local element, i.e. only local currents between that copper particle and the steel surface play a role for that kind of pit corrosion.

Another cause for corrosion at the outside surface of metal tubes is the air quality. F.e., a common mistake is to place detergents and cleaning chemicals under the sink where metal tubes/hoses are nearby. After some years, a leakage in the flexible hoses (even if made of stainless steel) may result from the steady aggressive damp in that closed, not well vented area.

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