Pex dezincification
昨天我碰巧读一篇老文章了a serious problem with Zurn pex fittings. Apparently, over time they can lose their zinc, become corroded and weakened and fail. They call it ‘dezincification.’ During this process, the fittings can actually give off lead which leaches into the water. There was a class action lawsuit that came and went unknown by me, in my ignorant bliss.
We plumbed our home with pex in 2007 and have been so happy with it, no complaints. However, after reading this article I thought I had better check the condition of the fittings. Some of them are visible in the utility closet and they do, indeed, look like they are corroding.
Has anyone else had this problem and, if so, how did you handle it? Zurn has replaced their brass fittings with plastic ones, which don’t inspire a lot of confidence.
Replies
I’m not sure how loosing zinc would also release lead. How old are these fittings? Lead-free solders, for example, have been required for decades now. Whether or not any metal will leach out of a fitting into the water depends on the water chemistry. The widely publicized water issues in Flint were due to the water authority there switching water sources (from the Detroit river to the flint river), and then cheaping out and not treating the water properly which resulted in lead leaching into the water in certain areas that had old pipes. I think the treatment they cheaped out on resulted in too-low phosphate levels but I may not be remembering correctly on that part.
It is entirely possible your fittings are only corroded on the outside and are fine inside the pipe. I have this problem at work with very large chilled water systems. The corrosion inhibitors work great inside the pipe where they are not exposed to air, as soon as they leak out they seem to become corrosion enhancers on the outside of the pipe where exposed to air.
The only way to be sure would be to cut one of the fittings open to inspect it. You may find that they’re fine, in which case you don’t need to worry about the others. If one is corroded, they probably all are due to them all being exposed to the same water chemistry. I can tell you that my mechanical contractors love PEX, but they only trust the compression type fittings that are installed with a big crimp tool. I don’t trust the push-in fittings long term.
Bill
Thanks, Bill, I sure hope you're right. My fittings are from 2006. Here's a few links on the subject:
http://www.plumbingfittingsettlement.com/FAQ.aspx
https://inspectapedia.com/plumbing/PEX_Brass_Fitting_Leaks_De_Zincification.php
https://www.nace.org/Corrosion-Central/Corrosion-101/Dezincification/
Here's an example of a fitting I am worried about. It really looks like it's about to let loose, to me (the crimp ring, at least).
That connection looks just fine to me, a little surface discolouration is all I see. The right hand one is asymmetrical, but it started out that way with a poor angle on the crimper when they installed it, not because it has shifted at all. As long as it held then it was first pressure tested, I can't see why it would let go now. As Bill said, it might be worth taking one out and looking at the inside to reassure yourself.
Thanks, guys, this has taken a load of worry off my mind. I would like to take one off and get a better look at it but sounds like it's not terribly urgent.
One question maybe one of you might know the answer to, I have a water softener in this utility closet and wondering if dumping the salt into it may get into the air and corrode things faster?
Yes, I have had this happen. Some type of coating (like LPS3) might help.
Those are not exposed to water so unless metal is migrating through the plastic you should be okay.
That said they would be corroding by contact with air so they are likely corroding from the outside in.
Also they should have no lead in them to leech, or do they?
The fitting in the pic you posted looks fine. It just shows the usual petina grass gets as it ages. Corrosion would usually be a blue/green color and would have a crusty look to it.
Your fitting is older than the date lead-free fittings were mandated. I wouldn’t worry about that though, any lead content will be very small and you’re unlikely to have any signfitidant leaching unless you have strange water chemistry (acidic).
Regarding the salt in your water softener, that could be a concern, but it’s easy to minimize any risks. Usually either high-quality pelletized salt, or block salt. With block salt you’ll have no dust but they’re more difficult to handle. Pellets have minimal dust. Don’t use rock salt, it’s dusty and the dirt in it will gradually clog your softener.
Bill