Water Line Leaks? Fix It Yourself! Here's How...

Are the water supply lines under your sink leaking?  Did a cracked or broken plastic fitting cause your bathroom to flood?  Should you call a plumber?......not if you like saving money!

You can fix it yourself!  Here's how...

This instructable addresses how to repair or replace a PEX water supply line.


How do I know whether or not my water supply line is PEX?

There are three easy ways to identify PEX tubing:

Note:  If the first two identifying features are not true of your water supply line, please do not attempt the third.  Bending a PVC or Copper supply line will not end well!

1)   PEX tubing comes in two different colors, solid white and solid red.  (White denotes a cold water line, while red denotes a hot water line).
2)   PEX tubing has printed lettering that contains the words "PEX" (see figure below).
3)   PEX tubing is rather flexible and easy to bend.  (Be careful not to break your supply line by testing its flexibility).


If you have safely identified your water supply line as PEX tubing, then it's your lucky day!  Continue reading to learn how you can easily repair your water lines.

All of the tools that you will need to replace or repair your PEX water lines can be found in the image below.  These tools include:

- Flashlight :  So you can see what you are doing underneath the sink!

- Safety Glasses :  Safety first!

- Tape Measure :  For measuring the tubing that will be replaced, as well as the new replacement tubing.

- 1" PVC Pipe Cutter:  Used to safely cut the PEX tubing,  this PVC cutter can be purchased at your local hardware store for around $10.00.   A PEX tubing cutter may also be used, both cutters provide the same results.

-  One Hand PEX Cinch Clamp Tool : The cinch tool pictured below is an "Apollo" One Hand PEX Cinch Clamp Fastening Tool, Model: 69PTBJ0010C.  This tool was purchased at Lowes, a local home improvement store, for around $80.00.  The pictured tool has a nice LED feature that alerts the user when proper force has been applied to the cinch clamp.

Hang on, I know what you are thinking...that's a lot of money for a silly tool!  I too, was a little leery of spending that kind of money.  However, I have used my cinch tool to replace nearly thirty fittings in my home.  It would have cost hundreds of dollars to pay a plumber to do what I was able to do for far less!

First:  Determine the size of PEX tubing.

The tubing size is printed on the side of the tubing.  If these markings are not visible, measuring the inner diameter of the tubing is a sure bet.  Common sizes of PEX tubing include: 3/8", 1/2", 3/4", and 1".

Second:  Figure out what components you need to replace.

Water leaks are fairly easy to spot, so you should be able to pin point which fitting(s) or section(s) of tubing are leaking.  Once you pin point the leak, cut out that section of tubing and take it with you to the hardware store.   Note: Instructions for doing so can be found in Step 5 of this instructable.

Third:  Brass or Plastic?

When you arrive at the hardware store, with your section of tubing in-hand, you will be faced with a choice of replacing your fittings with brass or plastic.  Personally, I used all brass fittings in my home.  Although they cost a bit more, brass fittings will not become brittle or weak like the plastic fittings.

Fourth:  White or Red?

PEX tubing comes in two different colors, solid white and solid red.  (White denotes a cold water line, while red denotes a hot water line).  Buy the color of tubing that matches the tube that you will be replacing.



First Picture:  A variety of common replacement fittings and supplies that you can find at the local hardware store.


Second Picture:  For this instructable, we will be replacing a section of 1/2" tubing that contains the following components:

PEX FPT Swivel - Screws into the bottom of the faucet on your sink or shower.

PEX Ball Valve - Usually installed to allow the user to quickly stop the water supply to a sink or shower.

PEX Tubing - This is a section of cold water supply line.  PEX tubing is most commonly sold by-the-foot.

PEX Stainless Steel Pinch Clamps - These clamps are used to secure the PEX tubing to the PEX fittings.  They are generally sold in a pack of 10 and are available in all sizes.

Shutting off the water

Before you begin your plumbing adventure, locate the water main shut off valve for your home.  Turn the valve off.  You can release the water pressure in the line that you will be working on by turning on the faucet that the line is supplying water to.  This will also allow you to double check that the water is, in fact, off.

Removing the old section of tubing

After you have successfully shut off the water main, you are ready to begin your plumbing adventure!

Begin by cutting the PEX tubing directly below the leaky fitting.  In this case, the tubing was cut directly below a leaky, plastic shutoff valve.  Note: It is important that you hold the pipe cutter perpendicular, or 90 degrees, to the pipe while cutting.

If the other end of the tubing is screwed into the bottom of the faucet, you will need to disconnect it from the faucet by turning the fitting in the counterclockwise direction.

Once you've removed the leaky section of tubing, you will need to pay a visit to the local hardware store to purchase the necessary replacement components.

Cutting the new section of tubing

Next, you will need to cut the new PEX tubing to the correct length.  Using the old section as a guide, measure the length of new tubing and make a mark where the cut is to be made (a permanent marker works wonderfully!).  Note: It is always better to cut the pipe a little too long, rather than a little too short.

After the mark is made, use the pipe cutter to cut the tubing.  Again, be sure to hold the pipe cutter perpendicular, or 90 degrees, to the pipe while cutting.

Attaching the fittings to the new section of tubing

7a.)  It always helps to set the parts out in the fashion that they will be assembled. 

7b.)  Start assembling the parts by pressing the FPT Swivel into one end of the PEX tubing. 

7c.)  Make sure that the fitting is fully seated against the end of the tubing. 

                If there is a gap (more than 1/8"):  Try repositioning the fitting.  If the gap still exists, exceeding 1/8", a new section of tubing needs to be cut.  The key to a good cut is keeping the pipe cutter perpendicular to the pipe.

              If there is little to no gap (less than 1/8"):  Proceed to the next step.

7d.)  Notice the gap on the end of the cinch tool.  This gap needs to be placed over the raised tab on the pinch clamp.

7e.)  Keeping the tool in place, position the pinch clamp 1/8" below the end of the PEX tubing.

7f.)  Maintaining the 1/8" spacing, squeeze the handle of the cinch tool multiple times until the LED light is illuminated.  Once the LED light is illuminated, stop squeezing!  The LED light is designed to alert the user when the proper force has been applied.  Next, turn the release knob counterclockwise to release the part.

7g.)  You should always inspect the pinch clamp after it has been installed.  The installed pinch clamp should look identical to the one pictured below.  For safe measure, you can try pulling the fitting out of the tube.  If done right, the fitting should not even begin to slip out of the tube. 

If the pinch clamp does not look like the one pictured below, or the fitting begins to slip out of the tube when pulled, then the pinch clamp needs to be removed and replaced. 
Note:  Removing a pinch clamp can be a strenuous process.  I always wear gloves when I attempt to remove a pinch clamp, so I don't remove a part of my finger!  I've found that a pair of needle nosed or thin-nosed pliers works best when removing unwanted pinch clamps.  Good luck!

7h.)  Slip the second pinch clamp over the free end of the tube.

7i.)  Press the ball valve fitting onto the free end of the tube.
Note:  If you want the valve handle to point down when the valve is open, orient the valve as shown below.  If you prefer the handle to point upward when the valve is open, orient the valve with the handle pointing toward the FPT.  For a better understanding, see step 10.


Repeat steps 7c through 7g

Installing the new section of tubing

Start by sliding a pinch clamp onto the existing PEX tubing. 

Next, slide the free end of the ball valve into place. 

Using the cinch tool, repeat the clamping process that was explained in Steps 7c through 7g. 

You have successfully installed the new section of tubing!

Fastening the FPT Swivel to the faucet

Finish by screwing the FPT Swivel into the bottom of the faucet. 

Turn the valve to the off position (perpendicular to the tubing).

Turning the water back on

Check to make sure the faucet handle is fully open.

Double check to be sure that the valve is in the off position (perpendicular to the tubing).  You may now safely turn the water main to the house back on.

After turning on the water main, you may slowly turn the valve to the on position.

Water should begin to flow immediately after the valve is opened. 



Finish by checking over your fittings and faucet to be sure that there are no water leaks. 

CONGRATULATIONS!  You have successfully repaired your leaky water line!