PEX Crimp Fitting Leaking? Check It With a Go/No-Go Gauge

A leaking PEX crimp joint usually traces back to how it was made: a crimp tool out of calibration, a ring in the wrong spot, the tool held crooked or not closed all the way, or a bad cut on the pipe. You cannot tighten a crimp. Test it with a go/no-go gauge; if it fails, cut the joint out (or pull the ring with a removal tool), check your tool’s calibration and make a new connection, the way SharkBite’s instructions lay out.

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Test before you guess: a go/no-go gauge tells you in seconds whether the ring was crimped right. Not linked: on 10/3/2026 the Amazon listing was sold by a third-party seller, not by Amazon or the maker.

Safety first: shut off the water to that line and open a faucet below it to relieve the pressure before you cut into any joint.

Why PEX Crimp Fittings Leak

SharkBite’s crimp instructions list what makes a good joint. A leak usually means one of these was missed:

The crimp tool is out of calibration. SharkBite says to make sure the tool is calibrated before you start, and that a tool is out of calibration if neither side of the go/no-go gauge slides over the finished crimp.
The ring is in the wrong place. It belongs 1/8 to 1/4 inch from the fitting shoulder.
The tool was crooked or not closed. The jaws go over the center of the ring, at 90 degrees to the fitting, and the handles close completely.
The pipe end was bad. SharkBite says to cut the PEX as cleanly and squarely as possible and make sure it is free of scratches and debris.
The wrong tool for the ring. SharkBite crimp fittings take either copper crimp rings or stainless steel clamp rings, but each has its own tool: a crimp tool closes a copper ring, and a clamp tool squeezes the ear of a clamp ring. The differences are in PEX crimp vs clamp.

Check the Joint With a Go/No-Go Gauge

SharkBite includes a go/no-go gauge with its crimp tool. Slide it over the crimped ring:

Go side slides on tightly, No-Go side does not slide on at all: the ring is crimped correctly. If that joint leaks, look at the pipe end and the fitting.
Neither side slides on: SharkBite says the tool is not properly calibrated.
The No-Go side slides on: the connection fails the test.
Stainless clamp (cinch) rings: the gauge is for copper crimp rings. SharkBite says to check a clamp ring visually for a correct closed-ear form.

How to Fix a Leaking PEX Crimp Joint

Shut off the water and drain the line.
Remove the bad joint. SharkBite gives two ways: cut the pipe as close to the end of the fitting as you can to save pipe, or, to keep the fitting, use a crimp ring removal tool, cutting the ring on at least two opposite sides and taking it off. Our guide on how to remove a PEX crimp ring covers the removal.
Check the tool’s calibration. For the SharkBite PEX crimp tool: close the handles gently until the jaws touch and measure between the handles. SharkBite says the proper range is 8-1/4 to 8-3/4 inches. To adjust, remove the eccentric set screw, push the eccentric up and turn it to change the handle width, then retighten the set screw. Other brands differ; use your tool’s own instructions.
Make a test crimp on a scrap piece and check it with the gauge before you touch the real joint.
Cut the pipe clean and square, free of scratches and debris. If the cut-back pipe is now too short, add a short piece of new PEX and a coupling.
Make the new joint. Slide a new copper crimp ring onto the pipe, push the barb fitting into the pipe, then set the ring 1/8 to 1/4 inch from the fitting shoulder, center the jaws on the ring at 90 degrees and close the handles completely.
Gauge it, then turn the water on slowly and watch the joint.

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Parts That Fix It

These cover the gauge check, the removal and the new joint for 1/2-inch PEX. Each was sold or shipped by Amazon, new and in stock, when we checked on September 24, 2026; details come from each Amazon listing.

A go/no-go gauge. The SharkBite PEX crimp tool go/no-go gauge (23080) covers 3/8, 1/2, 3/4 and 1-inch crimps; the listing says it checks that copper crimp rings are fully compressed.
A crimp ring removal tool, to save the fitting. The SharkBite PEX crimp ring removal tool removes copper crimp rings from brass or poly crimp connections so the fittings can be reused, per the listing, and works on 1/2, 3/4 and 1-inch rings.
New copper crimp rings. SharkBite 1/2-inch copper crimp rings, pack of 25: for brass or poly PEX crimp fittings on PEX or PE-RT, per the listing. Never reuse a cut ring.
A coupling, if the pipe came up short. SharkBite 1/2-inch brass crimp coupling, pack of 10: joins two pieces of same-size PEX with copper crimp rings or stainless clamps, per the listing.

Need a new crimp tool? See our best PEX crimp tools. A clean cut starts with a sharp PEX cutter.

When to Call a Licensed Plumber

The leak is inside a wall, ceiling or floor you cannot open safely.
Several crimp joints are weeping, which points to a tool that was out of calibration for the whole job.
A new, gauged joint still leaks.
You cannot tell whether the pipe is PEX, PE-RT or something else.

FAQ

Can you tighten a leaking PEX crimp fitting?

No. A crimp ring is compressed once; there is nothing to tighten. SharkBite’s instruction for a connection that fails is to cut it out, or remove the ring with a crimp ring removal tool, check the crimp tool’s calibration and make the connection again.

How do I know if a PEX crimp is good?

Check it with the go/no-go gauge. SharkBite says the Go side should slide tightly over the crimped ring and the No-Go side should not slide over it at all.

Can you recrimp a PEX crimp ring?

Do not rely on crimping the same ring again. SharkBite’s instruction when a connection fails the gauge is to cut it out or remove the ring, make sure the tool is calibrated, and make a new connection.

Where should the crimp ring sit on the fitting?

SharkBite says to position the crimp or clamp ring 1/8 to 1/4 inch from the fitting shoulder, then center the crimp tool’s jaws over the ring and keep the tool at 90 degrees to the fitting.

Why did my PEX crimp fail the go/no-go gauge?

Often the tool is out of calibration. SharkBite says the tool is not calibrated if neither side of the gauge slides over the connection. Its crimp tool is calibrated when the handles measure 8-1/4 to 8-3/4 inches apart with the jaws just touching.

Why Trust Plumbing Picks

Plumbing Picks is written by a licensed Georgia plumber — journeyman license #JP507711 — and the license is verifiable through the Georgia Secretary of State’s license verification portal. The steps on this page follow the manufacturer sources listed below, and product details come from the Amazon listing or the maker, not from hands-on testing. Nobody pays to be included here. Where a link goes to Amazon we may earn a commission at no extra cost to you. More on who writes this and how we pick.

Sources

Bottom Line

A crimp joint cannot be tightened. Check it with a go/no-go gauge; if it fails, cut it out or pull the ring with a removal tool, calibrate the crimp tool, and make a new joint with the ring 1/8 to 1/4 inch from the shoulder and the jaws square and fully closed. Gauge every joint before the water goes back on.

PEX Crimp Fitting Leaking? How to Find and Fix a Bad Crimp