Pipes & water supply

PEX pipe fitting leak

A leaking PEX connection is usually a fitting that wasn't crimped, clamped, or expanded properly, and is generally straightforward to redo with the right tool.

Difficulty
Moderate
Time
20–40 minutes
DIY cost
$10–$30
Pro cost
$150–$300

Symptoms

  • Drip or spray at a crimp ring, clamp, or push-fit connector
  • Leak worse under water pressure
  • Fitting may look slightly loose or off-center
  • Connection is relatively new or recently worked on

Likely causes

  • CommonCrimp or clamp ring not properly compressedIf the crimping tool wasn't calibrated or fully closed, the ring won't seal tightly enough around the fitting.
  • CommonPipe not inserted fully onto the fitting before crimpingPEX needs to bottom out against the fitting shoulder; a shallow insertion leaves a gap that leaks.
  • PossiblePush-fit connector not fully engagedThese fittings require the pipe to be pushed in until it hits a stop, and partial insertion causes leaks.
  • Less commonDamaged or cracked fittingA fitting stressed during installation or exposed to freeze damage can crack even if properly connected.

What to do

  1. Shut off water to the affected line before attempting a repair.
  2. Cut out the leaking connection cleanly with PEX cutters or a hacksaw.
  3. Inspect the pipe end for any damage or ovaling and trim further back if needed.
  4. For crimp connections, slide on a new crimp ring, insert the pipe fully onto the fitting until it stops, then crimp with a properly calibrated crimping tool, checking with a go/no-go gauge if available.
  5. For clamp (cinch) connections, use the correct clamp tool to compress the stainless steel ring evenly around the fitting.
  6. For push-fit connectors, make sure the pipe is cut square and pushed in fully until you feel it seat against the internal stop.
  7. Turn water back on slowly and check the new connection closely for leaks under both low and full pressure.

Tools and parts

  • PEX cutters
  • Crimp or clamp tool
  • Go/no-go gauge
PEX fitting and crimp/clamp ringsSearch: “PEX crimp fitting and rings kit”

When to call a pro

Call a plumber if you don't have the correct crimping or clamping tool, since using the wrong tool often causes the same leak to recur.

Safety

Generally low risk

Generally low risk for a careful person. Stop if anything looks different from what this guide describes.

Related guides

Operator provides AI-generated troubleshooting information. It can be wrong. For safety-critical, electrical, gas, structural, medical, automotive safety, or other high-risk problems, consult a qualified professional.