How to Install a Shut Off Valve on PEX Water Lines: An In-Depth DIY Guide

Adding a shut off valve to your PEX water lines enables you to easily control the flow of water in your plumbing system. This in-depth DIY guide will provide you with everything you need to know to successfully install a valve on PEX tubing. I‘ll walk you through the entire process with step-by-step instructions, pro tips, safety information, cost breakdowns and more. By the end, you‘ll be able to install a reliable shut off valve like a professional plumber.

What is PEX Tubing?

Overview and Benefits

Before we get into the installation process, let me provide some background on PEX tubing. PEX stands for "crosslinked polyethylene” and it has become a very popular option for water supply lines in homes and businesses.

There are several reasons plumbers and DIYers choose PEX:

• Extremely flexible – can easily maneuver around corners and obstacles.
• Withstands freezing without bursting.
• Resistant to scale buildup and corrosion.
• Less expensive compared to copper plumbing.

In addition to being affordable and flexible, PEX offers superior durability and is easy to install with fewer connections than metal pipes. The crosslinking manufacturing process also makes it more heat resistant. No wonder PEX usage has grown over 500% in the past 15 years!

Types of PEX Tubing

While all PEX is polyethylene plastic, there are three distinct manufacturing methods that differentiate the types:

• PEX-A – Made using the Engel method to produce the most flexible and durable PEX tubing. Considered top of the line.
• PEX-B – Uses a silane process to generate PEX that is slightly stiffer but still very reliable.
• PEX-C – Uses an electron beam to modify the polyethylene. Most rigid type of PEX.

The type of PEX printed on the tubing indicates which manufacturing process was used. However, any PEX type can be used for your shut off valve installation.

Gather the Right PEX Plumbing Tools

To install a valve on a live PEX water line, you’ll need to cut into the existing tubing. This requires having the proper PEX-specific plumbing tools on hand. Trying to improvise with regular tools can lead to damaged pipes or injury.

Here are the essential tools you’ll need:

• PEX tubing cutter ($10-$50) – Specialized cutter that won’t crush the tubing on tightening.
• PEX crimp rings and crimp tool ($25-$100) – For secure metal-to-plastic connections.
• Deburring tool ($5-$15)- Bevels cut tube ends smooth so water flows easily.
• Pipe wrench ($15-$30) – For tightening fittings and valves.

Optional tools include sandpaper, emery cloth, PTFE plumber’s tape, a utility knife, and safety glasses. Investing in quality tools will make your plumbing projects easier for years to come.

Choose the Right Shut Off Valve

Now that we’ve covered the basics of PEX tubing and the required tools, it’s time to pick out a shut off valve compatible with PEX. Here are your main options:

PEX Ball Valve

This is the quickest and easiest choice for DIY PEX valve installation since the ends directly connect to PEX tubing without requiring additional fittings. Just cut the PEX, insert into the valve ends, and tighten the compression fittings. Durable, leak-proof, and the valve operates with a simple quarter turn.

PEX Gate Valve

Similar direct PEX connection as a ball valve. The difference is gate valves use an internal wedge that lifts up to stop water flow. Takes more rotations to open and close compared to a ball valve‘s 90 degree range.

Standard Ball or Gate Valve

You can also use a standard brass or plastic ball or gate valve. However, these require separate fittings to adapt to PEX tubing on the inlet and outlet sides. More time consuming to install.

No matter what style you choose, match the valve size to your PEX tubing diameter. The standard for residential use is 3/4" PEX. Getting the same size valve avoids reductions and the risk of flow restriction.

Step-By-Step PEX Shut Off Valve Installation

Now we’re ready to walk through the installation process step-by-step. I’ll explain each stage in detail so you know exactly how to install your new PEX shut off valve.

Step 1: Turn Off the Main Water Supply

Locate the main water shut off valve for your home and turn it to the closed position. This stops the flow of water in your plumbing system so you can safely cut into the line.

If you don’t have a main valve, turn off the individual supply valves for the fixture the PEX line is connected to.

Step 2: Cut the PEX Tube

Decide on the ideal location for your new valve. Leave room on either side for the valve connections.

Use the PEX tubing cutter to make a straight cut across the tube. Go slowly and gently to avoid deforming the pipe. Twisting the tubing while cutting can help make a clean cut.

Step 3: Smooth the Pipe Edges

Use a deburring tool to gently smooth out the interior and exterior of the freshly cut PEX edge. This removes any ridges or plastic fragments so water can flow smoothly.

Step 4: Sand the Pipe Ends

Lightly sand the ends of the PEX tubing that will connect to the valve. This roughens up the surface allowing the fittings to form a tighter seal. Wipe away plastic dust when done.

Step 5: Position the Valve

Place the new PEX shut off valve up against the cut tubing ends. This will help you visualize the correct positioning before making the actual connections. Allow space to tighten fittings.

Step 6: Connect the Valve

Push the PEX tubing into one end of the valve until it seats firmly against the internal gasket. Tighten the compression fitting nut first by hand, then use the pipe wrench for an additional quarter turn. Repeat for the other end.

Step 7: Restore Water Supply

Slowly turn the main water supply back on while checking closely for leaks at the valve connections. Fully open and close the valve multiple times to confirm smooth operation.

And that‘s it — you‘ve successfully installed a shut off valve on your PEX water lines!

Connecting a PEX Valve to Other Pipe Materials

What if you need to connect the new PEX valve to existing copper or PVC plumbing lines? No problem. Here are a few options:

• Use push-to-connect fittings which form a compression seal without requiring tools.
• PEX-to-male threaded adapters allow connecting to standard threaded pipe.
• Sharkbite couplers directly join PEX to copper, PEX, and CPVC.

PTFE plumber‘s tape should always be used on threaded male connections to prevent leaks. Follow the valve manufacturer‘s instructions for proper installation.

Testing for Leaks like a Pro

Once your PEX ball valve is installed, it‘s crucial to thoroughly test for leaks before leaving the project. Here are two methods:

Visual Inspection

Carefully check the full circumference of the valve connections for any water droplets. Tighten fittings slightly if small leaks are spotted. Wipe joints completely dry between checks.

Soap Bubble Test

Spray soapy water onto the connections and look for growing bubbles, indicating a gas or water leak. Tighten fittings or reinstall tubing to stop leaks before moving on.

Verifying leak-free connections prevents damage down the road. Give connections a final tightening if they seep even slightly.

Troubleshooting Common PEX Shut Off Valve Problems

Despite best efforts, issues can arise with PEX valve installations. Here are some common problems and solutions:

• Leaks at fittings: Further tighten compression fittings by hand first, then 1/4 turn more with wrench if needed.
• Valve won‘t turn: Loosen compression fittings slightly to reduce strain on valve.
• Reduced water flow: Check for debris stuck in valve interior and clean out.
• No water flow: Confirm water supply is on and valve is fully open.

Replacing old, faulty shut off valves is straightforward using the installation steps covered earlier. Make sure to turn off water supply first and have towels handy to catch drips.

Cost Breakdown: DIY vs Professional Installation

Installing a shut off valve on PEX tubing yourself can save a substantial amount of money in plumbing fees. Let‘s compare:

• DIY valve and supplies: $20 – $50 (PEX valve, fittings, tools if needed)
• Professional install: $200 – $350 (average plumber hourly rate of $50 – $100 plus materials)

As you can see, a professional PEX valve installation costs about 4-5 times as much as doing it yourself. And with the instructions provided here, you can achieve results on par with a licensed plumber.

Safety Tips for PEX Plumbing Projects

Working on home plumbing systems comes with certain risks. Keep these safety tips in mind:

• Wear eye protection when cutting PEX tubing to prevent injuries.
• When soldering, have a fire extinguisher nearby and work in a well-ventilated area.
• Allow pipes time to fully cool before handling to avoid burns.
• Use a bucket, tray or rag to catch water drainage when cutting lines.

Proceed cautiously and stop to reassess anytime you feel unsafe performing a step of the installation. Having patience goes a long way for maintaining plumbing safely.

Alternatives to Ball Valves for PEX

While ball valves are a top choice for controlling water flow, other valve styles can be used:

• Gate Valve – Gets its name from the gate-like wedge that lifts to stop water flow. Needs many turns to open fully.
• Butterfly Valve – Rotates a disc to obstruct flow. Quick opening but not as leak-proof.
• Plug Valve – Rotates a tapered plug with a hole to regulate flow. Prone to wear over time.

Each has pros and cons for use in PEX plumbing systems. The best valve for your needs depends on flow rate, pressure, and frequency of use.

Installing Shut Offs for Washing Machines

It‘s recommended to install dedicated shut off valves for appliances like washing machines and dishwashers. This provides an isolation point to stop water flow for maintenance.

Use a T-fitting to split from the main PEX line. Install the new valve on the branch downstream from the T-connector. Follow the same installation process outlined above.

Having appliance-specific shut offs adds convenience and prevents extensive water damage if a hose bursts.

Maintaining PEX Shut Off Valves

Installing a PEX ball valve is the first step—maintaining it over time is equally important:

• Periodically inspect valves for drips or leaks and tighten fittings if needed.
• Open and close valves twice per year to verify smooth operation.
• Check valves near exterior hose bibbs for frozen, damaged pipes in winter.
• Proactively replace old valves that are seized up or leaking heavily.

Maintaining your PEX plumbing valves helps prevent pipe bursts and leakage damage down the road.

Conclusion

That covers everything you need to know to successfully install a new shut off valve on PEX water lines. Following these steps will enable you to add a reliable shut off point and isolate sections of your plumbing system.

The most important takeaways are:

• Invest in quality PEX-specific tools to avoid tubing damage.
• Choose an appropriate valve style and size for your application.
• Make watertight connections by sanding PEX ends and tightening fittings properly.
• Confirm leak-free operation using visual inspection and soap bubble tests.

With the right materials and some mechanical aptitude, you can install a professional-grade shut off valve on PEX tubing and save significantly compared to hiring a plumber.