Monday, December 5, 2022


Ask Dave: How can I repair a leaking PEX water line?


Answers to questions about RV Repair and Maintenance from RV expert Dave Solberg, author of the “RV Handbook” and the managing editor of the RV Repair Club. This column appears Monday through Saturday in the RV Travel and RV Daily Tips newsletters. (Sign up for an email reminder for each new issue if you do not already receive one.) Today Dave discusses repairing a leaking water line.

Dear Dave,
What is the best and easiest way to repair a leaking water line made of PEX? And can I buy those fittings at a local hardware store? —Herb

Dear Herb,
PEX (cross-linked polyethylene) is a plastic tubing that has been used in the housing industry for more than 40 years. It is easy to install, costs much less than copper tubing, and is more flexible in the event of freezing. For years, RV manufacturers used 3/8” gray or beige mobile home type tubing known as polybutylene pipe.

The advantage of using PEX is not only is it flexible for installation with the ability to bend around structures rather than “sweating” elbows and fittings, but it also has the ability to expand without cracking if frozen. I personally have frozen the water lines several times (not always my fault) and was amazed when it thawed out that nothing cracked and there were no leaks! However, this is not a guarantee, as it depends on the type of fittings used. My units had the Flair-It™ system that is a plastic compression fitting, and it did not crack.

Flair-It compression fittings

So back to your question of how to repair a leaking water line

The easiest way to repair a leaking water line is to cut out the damaged part of the PEX line and use a stab-in connection or crimp type band clamp. If the PEX has a simple cut or hole, you can just cut the bad area out and slip the ends into the stab-in connection.

This type of connection is the easiest and can be found at most home improvement stores. Brands that I have used are PEX, SeaLand®, and Watts®, depending on the store. Most of these are rated at 150 psi or higher. Another option is SharkBite®, which is more expensive and can be found at Ace Hardware, Home Depot, etc. These connection fittings are rated for 200 psi, which is more than any RV plumbing system will ever experience.

Some plumbing experts recommend the crimp band

Some “old school” plumbing experts are not convinced the compression fittings will hold and recommend the crimp band, which requires a special tool.

Many RV manufacturers use this type of connection as the crimp band is much less expensive than the compression fittings. When you look at the number of connections needed in an RV plumbing system, the crimp band makes economical sense. However, for a quick fix, I have used the compression fitting with great success.

No matter what method you use, make sure you make a clean and straight cut on the PEX line. I like using a simple PVC cutter rather than a razor knife or tin snips, which can pinch or compress the tube and compromise the connection.

Read more from Dave here

Dave Solberg worked at Winnebago for 15 years developing the dealer training program, as marketing manager, and conducting shows. As the owner of Passport Media Creations, Dave has developed several RV dealer training programs, the RV Safety Training program for The Recreation Vehicle Safety and Education Foundation, and the accredited RV Driving Safety program being conducted at rallies and shows around the country. Dave is a leading expert in the RV industry and author of the “RV Handbook” as well as the Managing Editor of the RV Repair Club.


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1 year ago

Unfortunately, most leaks will occur in a place where space is limited, so the use of the crimp band will be difficult. SharkBite is about the only fitting I can find locally, I have never had one fail.

1 year ago

A Wrap pulled tight of the silicon tape will hold it until a more permanent repair can be made.
Keep a roll in your tool kit.

1 year ago
Reply to  tom

It can be permanent too.

Tim Bear
1 year ago
Reply to  Drew

True dat. I used Sharkbites to add shutoff valves to kitchen sink lines. Recently one began a little drip >> used tightly wrapped silicone tape a short distance both up- & down-stream from the leaky ‘bite’, and it’s held fine for months.

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