How to Install PEX Tubing | Square Cuts, Full Insertion

To install PEX tubing correctly, cut it square, clean the end, and push or crimp it into an approved fitting until it seats fully.

The fix for leaky PEX connections is almost never the fitting — it’s the preparation. A tube cut at an angle or pushed in only partway will fail no matter how expensive the fitting is. The good news: the entire process takes about a minute per joint once you know the two rules that matter — square cuts and full insertion to the tube stop.

SharkBite’s own installation guide for PEX (widely used across residential plumbing) is explicit on both points, and the same fundamentals carry across crimp, clamp, and push-to-connect systems. Before you buy fittings, the practical starting point is choosing tubing rated for potable water; systems carrying ASTM F876 and ASTM F877 certification meet the common third-party standards referenced throughout the industry. If you’re still picking pipe, our tested roundup of the best 1/4 inch PEX tubing options covers which rolls handle tight bends without kinking.

The Four Prep Steps That Decide Every Joint

Every PEX connection method — crimp, clamp, expansion, and push-to-connect — starts with the same preparation. Skipping any of these four steps is the most common cause of fittings that weep or blow off under pressure.

• Cut the tubing square. A PEX tubing cutter gives a clean 90-degree cut. A knife or saw leaves an angled or ragged end that won’t seat properly.
• Remove burrs and debris. Rough edges and plastic shavings break the seal between the tube and the fitting’s O-ring or barb.
• Inspect the end. SharkBite’s instructions state that fittings and tubing should be free of damage, foreign objects, and marks on the outside diameter. If the tube is scored or damaged, cut that section off and start fresh.
• Keep it clean until the connection is made. Dirt on the outside diameter is enough to make a push-fit connection leak.

One caution applies from the moment tubing arrives: PEX must not be exposed to direct sunlight. UV degrades the material, so store rolls indoors and install quickly once they’re out of the wrapper.

Push-To-Connect Fittings (SharkBite Style)

Push-to-connect fittings are the fastest route for DIY installations because they need no crimp tool, no ring, and no wait for glue. The fitting does the sealing work internally — but only if the tube reaches the stop.

SharkBite’s published steps for PEX read: cut the pipe square, make sure it’s clean and round, then push the tubing into the fitting with a slight twisting action until it bottoms out at the tube stop. The verification step is what most people miss. If you can see a gap, the tube isn’t fully seated, and the fitting will leak or detach under pressure.

The release collar is the ring at the fitting’s mouth. To remove the tube later, press the collar in toward the body of the fitting and pull the tubing free with a twist.

SharkBite’s instructions note that integral tube support liners are included in the fittings and must be in place before insertion. The support liner prevents PEX from collapsing inside the fitting under pressure, so never remove it and never insert tubing that’s too short to reach past it.

Crimp And Clamp Connections

Crimp and clamp systems use a metal ring compressed around the tubing over a barbed fitting. The cost per joint is lower than push-to-connect, but each joint needs the right ring and the right tool.

Mixing rings between brands or using stainless clamps where the system calls for copper crimp rings is a code violation and a leak waiting to happen.

The standard sequence for a crimp or clamp joint:

1. Slide the ring onto the tubing before inserting the fitting.
2. Push the tubing onto the barbed fitting until it reaches the shoulder — the raised lip at the base of the barbs. This is the equivalent of the tube stop on a push-fit fitting.
3. Position the ring 1/8 in to 1/4 in from the end of the tubing.
4. Crimp or clamp with the correct tool for that ring type, then check it with the go/no-go gauge that matches the tool. The gauge either fits or it doesn’t — if it won’t slip over the crimped ring, the crimp is undersized and must be cut out and redone.

Joints in PEX must use approved fittings under code guidance, and permitted joint types vary by jurisdiction. Local plumbing code controls what’s acceptable on your install, so check that before burying joints inside a wall.

Running And Supporting The Tubing

PEX doesn’t need a fitting at every turn the way rigid pipe does. Route it through drilled studs and secure it with straps or hangers at the intervals your local code requires. Bend supports let you make turns without adding fittings, which removes potential leak points and cuts cost.

Where PEX passes through studs, the hole should be slightly larger than the tubing so the pipe can expand and contract with temperature changes. Don’t kink the tubing on tight radius turns — a kinked section is a permanent weak point.