Why is my expansion PEX leaking at the plastic rings?
Expansion PEX pipes can develop slow drips where the pipe meets the elbows and plastic rings, even when installed perfectly. These unpredictable leaks are often caused by a defective formulation in early colored pipes, which experienced so many field failures that some plumbing companies completely switched brands.
What people tried
Every workaround mentioned in the threads below. We haven’t tested any of them — and nobody here is claiming they worked.
Found another way around this?
Share your steps and trade-offs so fellow engineers don't have to reinvent the wheel. No account required.
- 1Cutting off the damaged rings and pipe back to a square edge and installing a new expansion ring.Did this help you?
- 2Switching to alternative plumbing methods like crimp fittings or sweated copper.Did this help you?
- 3Filing a warranty claim with the pipe manufacturer to cover the repair costs.Did this help you?
- 4changed the layout and used brass elbows insteadDid this help you?
- 5always use the fittings made for the brand of pipe you’re usingDid this help you?
In their words
Unedited, grouped by where they were said, most upvoted first within each place, each linked to the thread it came from.
“I was turning off the main water to fix a bathroom sink and noticed these two blue pipes are slowly dripping right where they attach at the bottom (circled in red).”source ↗
“Anyone know what would cause a leak right at these plastic ring parts, and is this an easy fix or do I need to call a plumber?”source ↗
“Its just expansion pex done right. Sometimes it leaks. Literally the reason I hate expansion pex, you do it perfectly and theres still a chance it leaks.”source ↗
“They had to change the formulation of their early pipe because it experienced failures like this in the field. Not sure of the all the exact details but it was major for us as a company and we switched brands entirely for several years.”source ↗
“I had a U shaped layout and noticed it was leaking in between where the pipe meets the elbows.”source ↗