Electrolysis causing leaks in home water pipes - is this a real thing?
February 14, 2017 7:27 AM   Subscribe

Our plumber thinks our home electrical system (which is grounded to the water pipes) is causing pinhole leaks in our pipes. Our electrician is not so sure. Looking for a high-school chemistry textbook explanation of what might be happening!

Our house was built in 1977 and has copper pipes which occasionally develop leaks. After the latest one our plumber recommended calling an electrician and getting ground rods installed. He said that when the electrical system is grounded to the water pipes, a process similar to electrolysis wears away the metal and causes leaks. Old building codes allowed grounding electrical to the water system, modern code doesn't. The electrician quoted me $300 to install ground rods but seemed unconvinced that this would prevent future leaks. I also got the impression that he thought the electrolysis theory was, well, a bit woo-woo. I'll probably get the ground rods, but my inner scientist is curious -- is this a real thing? If so, what is happening? Googling turned up discussions of this issue on home repair sites, but no clear explanation. I'm looking for the sort of explanation you'd get in a high-school chemistry textbook, please!
posted by selfmedicating to Home & Garden (12 answers total) 1 user marked this as a favorite
Oh my.
I see lots and lots of houses. Hundreds or thousands each year. In my area it is code to have the jumper wire grounded at the water meter.
I have never ever heard of this theory. I'll ask some of my plumber friends and science friends and update if they have other light to shed.

The most common cause of leaks in copper pipes in my area is pipes that freeze or were frozen. No idea if that could be your problem.
posted by littlewater at 8:03 AM on February 14, 2017

I'm a condo association trustee in a ~100 year old building. We had this same issue a couple years back, and were given the same advice by the plumber we called in. Management company supported the recommendation and said they had seen it happen in other buildings they supported, and two residents - a former general contractor, and a current chemistry professor - explained the science behind it during one of our annual meetings. I can't remember the details, but everyone involved said it's A Thing that can happen. Since we made the repair, we haven't had a single new issue with the pipes.
posted by NotMyselfRightNow at 8:09 AM on February 14, 2017 [2 favorites]

FWIW, we had copper water pipes that leaked in two places within months of each other, and the plumber gave us the same explanation. This was in an area of the country that is not subject to frozen pipes.
posted by muddgirl at 8:28 AM on February 14, 2017

Acidity can eat away at copper. Check the pH of the water.
posted by SemiSalt at 8:37 AM on February 14, 2017 [1 favorite]

Is there lots of iron in your water? The previous owner of this house had to replace all the copper plumbing. The pipes got paper thin. If he'd put a filter between the well and the house it would have saved him lots of money.

I don't think the grounding has anything to do with it. Galvanic corrosion.
posted by Mr. Yuck at 8:44 AM on February 14, 2017

My dad was an electrician, and I have a degree in electrical engineering. This is totally a thing that can happen. It's a form of galvanic corrosion that occurs based on the mineral/salt content of the water and the electrical potential differences between areas of the plumbing.

Ground rods are far safer anyway, you should definitely have them installed.
posted by Pogo_Fuzzybutt at 8:45 AM on February 14, 2017 [5 favorites]

This is happening in my house. This is a real thing. The pipe thins, you get a pinhole. My insurance company didn't bat an eyelash when we told them what happened.
posted by kerf at 8:51 AM on February 14, 2017 [1 favorite]

is it city water? could be a factor in this as some city water has been know to eat copper pipes. this happened in Venice Fla USA
posted by patnok at 1:24 PM on February 14, 2017

(Just remembered that hard water most likely also a factor in our pipe leaks. The house had a whole-water softener but it was on the fritz for at least a year after we purchased the house, and probably before that.)
posted by muddgirl at 4:15 AM on February 15, 2017

Yes, this is apparently a thing. It happened to our house in a non-freezing area of California when I was a kid in the late '80s. (I think the house was built in the '60s.) Our water service from the mains was leaking; when the plumber dug it up, suddenly half our house had no electricity at all and the other half was at 220 V. It blew out our microwave oven.

At the time it was explained to us as reverse electroplating.
posted by heatherlogan at 6:11 AM on February 15, 2017

My friend in Oakton, VA had his whole house repiped after repairing the third leak. His plumber told him it would only get worse. It seems to be a particularly common problem in some DC suburbs.
posted by fedward at 12:59 PM on February 15, 2017

Best answers to Mr. Yuck & Pogo_Fuzzybutt for teaching me the phrase "galvanic corrosion" which is exactly what I was looking for. And to fedward for helping me make the decision to get the work done -- I am literally within walking distance of Oakton. Your friend and I might have the same plumber.
posted by selfmedicating at 4:46 PM on February 15, 2017

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