What Causes PEX Leaks

[Weekend Handyman]

I have done quite a few PEX projects in my house now and have never had a leak (knock on wood).

I am just curious, when you get called out for PEX leak, what are the most common causes you see?

 

[Plumber69]

Ive seen pex rings only clamped on 1/8th of the fitting and it wasnt leaking after 15 years. I cut it out bent the pipe off the fitting and it popped right off.

 

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[Jeff H Young]

Since I'm not a full time service plumber I've seen only a few. poor workmanship a major factor and just about the only one we can control. I would expect rats chewing be a common one. chaffing rubbing against something like a nail or sheet metal till it leaks.
I experienced a leak when I cut off type expansion nicked the barb with knife ever so slightly, it failed when reinstalled. again poor workmanship, but a lesson gotta keep our heads in the game

 

[Tuttles Revenge]

poor workmanship, nails, rats.. those are the 3 major. I have seen 1 instance where a tube was very close to a florescent lamp in a grocery store and the UV burned a hole through the tube.

 

[JohnCT]

poor workmanship, nails, rats.. those are the 3 major. I have seen 1 instance where a tube was very close to a florescent lamp in a grocery store and the UV burned a hole through the tube.

I heard a few years ago that a plumber bought commercial refills of Ivory Liquid Soap and mixed it with water and sprayed it (garden sprayer) on every PEX installation he did in areas where rodent infestation was an issue. The theory being that the soap is bitter and the rodents won't touch it. I know PEX is somewhat chemically transparent but basic soap might be inert.

Regarding UV, I put the slip-on foam insulation covers on the PEX in my basement as there is some indirect light through the basement slider. Cheap enough and can't hurt.

John

 

[Jadnashua]

If your holes through studs (and especially metal ones without proper grommets) are tight, it's easy to score the tubing.

Nicks or scratches on the ridges of fittings can be problematic. Improper placement or crimping of the ring can allow it to leak. WIth a go/n0-go tool, they can wear out after time.

WRT crimp versus expansion fittings, on expansion, improper placement of the ring can be a problem as can not inserting the fitting properly into the pipe.

While pex itself usually won't be damaged by freezing, that does not necessarily apply to the fittings, and UV exposure can damage it.

Crimp rings are trying to compress the tubing so the ridges can make a seal, so if it isn't tight enough, it will want to spring back to its original shape. That feature is what makes an expansion fitting work...the natural springiness of the tubing wants to evenly clamp down onto the fitting. PEX-A is the only version that that works on, as it has the most cross-linking, so has the best (strongest) memory of the original shape. The other types would tend to shear those bonds if you tried to expand them.

It does take good workmanship and a little knowledge to do this.

 

[James23912]

I built a new house and hired a guy I was told was a plumber, he was a hack maintenance guy somewhere, before I fired him he had run a good deal of the pex for the hot water base board, then I got a real outfit to finish the heating and there were two leaks from the first guy, both in the second floor joists, so Imhad to cut out newly finished sheet rock, each leak was from a crimp,ring not crimped properly.
Also, the first guy laid the pex right over the strapping, we use strapping to attach Sheetrock, so a 1 5/8ths Sheetrock screw would have gone right into the pex if I had not noticed it