How to Install a Shut-Off Valve in an Existing Copper Water Line - 33rd Square (2024)

Hey there! As a home improvement expert who loves renovations and plumbing projects, I‘m excited to guide you through installing a shut-off valve on your copper pipes. I know this seems intimidating, but trust me – with the right gear and my tips, you totally got this.

Shut-off valves give you crucial control over the water supply to parts of your plumbing system for repairs and upgrades. We‘ll tackle this project together step-by-step, and I’ll share my pro tips and tricks along the way. Let‘s do this!

Why Shut-Off Valves Are So Helpful

Before we dig in, let me quickly explain why having shut-off valves installed throughout your plumbing can make life easier:

  • Allows you to isolate and turn off water to certain fixtures or appliance for repairs. No need to shut off the main home supply.
  • Lets you shut off water to exterior taps and sprinklers to prevent pipes from freezing in winter.
  • Essential when installing new plumbing and fixtures. Lets you work on individual sections without disrupting everything.
  • Allows you to shut off water in an emergency leak or burst pipe situation.

Plumbers recommend having shut-off valves installed on water lines supplying toilets, sinks, washing machines, dishwaters, exterior taps, water heaters, and any lines supplying detached buildings/garages.

What You‘ll Need to Complete This Project

Let‘s go over the essential equipment and tools you‘ll need before starting:


  • Tape measure
  • Pipe cutter (get a wheeled cutter with ratchet chain for easiest copper cutting)
  • Adjustable wrenches (two 10" wrenches ideal)
  • Utility knife
  • Wire brush
  • Propane torch (a basic Bernzomatic TS4000 works great)
  • Emery cloth
  • Sandpaper (120 grit)
  • Rags
  • Bucket
  • Safety glasses and gloves (crucial for eye and hand protection)


  • Ball valve shut-off valve (1/2" or 3/4" size)
  • Copper couplings (4 needed – match size to your pipes)
  • Short copper tubes (2 needed, approx 4" long)
  • Lead-free solder (I recommend Harris Stay-Brite Silver-Bearing)
  • Soldering flux
  • Teflon tape
  • Masking tape
  • Spray bottle with soapy water solution (to test for leaks)

Safety First!

Working with torches and cut copper pipes can be dangerous if proper precautions aren’t taken. Before starting, make sure you have:

  • A fire extinguisher
  • Flame-resistant clothing (fire-retardant jacket, gloves, etc.)
  • Eye protection (safety glasses or goggles)
  • Well-ventilated workspace

Stay safe out there! Now let’s get to work.

Step 1: Turn Off the Main Water Supply

First things first – we need to shut off the water to the entire home at the main supply valve. This is usually located next to your home’s water meter.

Here‘s how to shut off main water supply:

  • Locate the main water supply shut-off valve (usually a blue or red handle on a pipe near water meter)

  • Use a wrench to turn the valve clockwise until tight

  • Go inside and open sink taps to confirm water is off

  • Leave main water supply shut-off for duration of project!

With no water flowing through the pipes, we can cut into them and make modifications safely. Trying to cut or solder a live pipe can lead to a massive flood!

Leave the main shut-off closed for the remainder of the project. Once we verify there are no leaks at the end, it can be turned back on.

Step 2: Expose the Section of Pipe

Now it‘s time to access the section of pipe where you want to install the new shut-off valve.

You‘ll need to cut away a portion of the wall, insulation or other materials hiding the pipe. I recommend:

  • Exposing around 8-12 inches of pipe on each side of planned valve location

  • Avoid removing too much material, as this can weaken support

  • For pipes in walls/studs, cut a small rectangular access hole vs. removing entire sections

Tips for Locating Pipes:

  • Look for vertical lines along joists and studs where pipes often run
  • Try an inspection camera to see inside walls
  • Use a stud finder to detect pipes within walls
  • Follow pipes back from fixtures to source

Choose a section of straight pipe, avoiding elbow joints, tees or other fittings if possible. This allows easier installation.

Once you’ve exposed the pipe section, it‘s time to measure and mark the cut lines.

Step 3: Measure and Mark Cut Lines

With the pipe exposed, we need to carefully measure and mark where the pipe will be cut to remove a section:

| Side 1 Cut Mark | | Side 2 Cut Mark |
|- Distance from valve end to end -| | – 1 inch beyond first cut mark -|

Measure carefully and double check your cut marks! It’s very easy to mess this up and end up with a valve that doesn’t fit the space correctly.

Step 4: Cut Out the Marked Section of Pipe

Now the fun starts – we get to cut out the section of pipe between those marks using a pipe cutter tool!

For copper pipes, I highly recommend using a wheeled pipe cutter. These make cutting copper super easy.

Here’s how to use a wheeled pipe cutter:

  • Place cutter chain over pipe lined up with cut mark

  • Tighten chain so wheel grips pipe but can still rotate

  • Firmly rotate cutter around pipe multiple times as wheel scores into metal

  • Keep rotating until pipe is cut through completely

  • Repeat the process for the second cut mark

  • Then use utility knife to sever any remaining thin strands

Go slowly and don’t force the cutter or you could damage it. Let the wheel do the work.

For tight spaces, a hacksaw can be used instead. Secure pipe to prevent vibration as you gently saw.

Step 5: Remove Cut Section of Pipe

You did it – time to pop that cut section out!

Start by disconnecting any lines or fittings attached to the cut portion. Unscrew them from surrounding fittings.

Then gently wiggle and rock the cut pipe piece back and forth while pulling it outward. It should detach cleanly.

Warning: Water may come pouring out once disconnected! Have a bucket and rags ready to catch any drips.

If it won’t budge, don’t force it. Try spraying lubricant like WD-40 into the joints to loosen things up.

With the section removed, we‘re ready to start prepping the open pipe ends for the new valve.

Step 6: Clean and Prep the Pipe Ends

Now we need to clean and prep the open pipe ends so that the new valve and fittings seal properly when soldered.

Here are the steps:

  • Smooth any burrs/sharp edges with sandpaper or emery cloth

  • Clean inside walls with a wire brush to remove gunk and corrosion

  • Wipe outer surface with a clean rag to remove all dirt and grease

The goal is to have smooth, clean pipe ends ready to solder. Avoid scratching too deeply into the copper with the wire brush.

Once prepped, we need to apply special soldering flux to the pipe ends before soldering.

Step 7: Apply Soldering Flux to Ends

Flux is a special paste-like chemical used in soldering copper pipes. It:

  • Cleans and preps the copper for soldering
  • Prevents oxidation while the joint is heated

To apply it:

  • Coat the outer rim of each pipe end with a thin, even layer of flux

  • Also apply a small amount just inside each pipe end

  • Twist pipe to evenly distribute flux all around

Avoid using too much! Thin, even coats are best. Have rags handy, as flux gets messy quick.

Okay, now we‘re ready to attach the new valve. Time to break out the torch!

Step 8: Assemble the New Valve Pieces

For this step, you‘ll need:

  • Shut-off valve
  • 2 short copper tubes (approx 4" long)
  • 4 copper couplings

Here‘s how to assemble the valve setup:

  1. Slide a coupling over each end of the shut-off valve. Leave 1/4" thread exposed.

  2. Wrap valve threads with Teflon tape to prevent leaks.

  3. Insert short copper tubes into each valve coupling until snug.

  4. Slide a coupling over each copper tube end.

The valve assembly is now ready to solder between the cut pipe sections. Ensure all fittings are pressed tight.

Step 9: Solder the Joints

This is the most fun and gratifying step, albeit a bit nerve-wracking for newbies.

We need to permanently seal all the joints together with liquid solder metal.

Safety Reminders:

  • Work in a well-ventilated area
  • Have a fire extinguisher nearby
  • Wear protective goggles and gloves

Here are the soldering steps:

  1. If flux dried, re-apply to joints and pipe ends.

  2. Insert valve assembly fully into the cut pipe sections.

  3. Align parts so joints are flush and valve is straight.

  4. Secure joints with tape/clamps to prevent movement.

  5. Light torch and adjust flame to 1" blue point.

  6. Starting 1-2” from valve, heat joint until bright red.

  7. Apply 1/4” solder to opposite side, allowing it to melt into joint. Add more as needed.

  8. Repeat for each joint, fully heating before applying solder.

  9. Allow to fully cool before handling.

Don’t overheat the joints, and use the bare minimum solder needed. The key is even heating – the solder flows on its own into properly heated joints!

Reheat any joints with poor flow or gaps in the solder. And remember – patience and practice makes perfect here.

Step 10: Reconnect Any Removed Water Lines

Almost home free! Now we just need to reconnect any water lines that were previously attached to the cut pipe section:

For compression fittings:

  • Slide compression sleeve and nut over pipe end
  • Insert pipe fully into fitting
  • Hand tighten nut, then finish tightening with wrench

For soldered joints:

  • Clean pipe end and apply flux
  • Heat with torch until end is bright red
  • Apply solder and allow joint to cool

Ensure all reconnected lines are fully seated and watertight.

Step 11: Test Valve and Check for Leaks

Here comes the moment of truth! Time to:

  • Turn main water supply back on slowly

  • Thoroughly test shut-off valve operation (no drips when off)

  • Spray soapy water on all joints and connections

  • Tighten any leaky fittings immediately

  • Confirm no leaks with valve turned back on

Don’t be discouraged if you see a few leaks – this happens sometimes. Just detach the leaky joint and resolder it using the steps previously covered.

With no leaks present – congratulations, you did it! Enjoy having much easier access to your home‘s water system. Nice work!

And there you have it – a complete guide to installing a shut-off valve on an existing copper pipe. Thanks for letting me walk you through it – I hope this helps explain the process clearly so you can take on this project yourself!

If you run into any hiccups or have additional questions, don‘t hesitate to contact me. I‘m always happy to provide tips and advice to help you master home plumbing and take on new projects with confidence.

How useful was this post?

Click on a star to rate it!

Average rating 3 / 5. Vote count: 2

No votes so far! Be the first to rate this post.


You May Like to Read,

  • How to Cut Pastry into Perfect Diamonds: The Ultimate Guide
  • The Complete Expert Guide to Deep Cleaning and Disinfecting Carpets
  • The Complete Guide to Drawing Fortnite‘s Iconic V-Bucks
  • How to Fix a Broken Cabinet Door Panel: An Expert DIY Guide
  • How to Fix a Loose Kitchen Faucet Lever
  • How to Fix a Shower Knob That Keeps Turning: The Ultimate Troubleshooting Guide
  • How to Fix a Toilet That Runs Too Long After Flushing
  • How to Fix Uneven Blinds: A Comprehensive DIY Guide
How to Install a Shut-Off Valve in an Existing Copper Water Line - 33rd Square (2024)
Top Articles
Latest Posts
Article information

Author: Nicola Considine CPA

Last Updated:

Views: 5953

Rating: 4.9 / 5 (49 voted)

Reviews: 88% of readers found this page helpful

Author information

Name: Nicola Considine CPA

Birthday: 1993-02-26

Address: 3809 Clinton Inlet, East Aleisha, UT 46318-2392

Phone: +2681424145499

Job: Government Technician

Hobby: Calligraphy, Lego building, Worldbuilding, Shooting, Bird watching, Shopping, Cooking

Introduction: My name is Nicola Considine CPA, I am a determined, witty, powerful, brainy, open, smiling, proud person who loves writing and wants to share my knowledge and understanding with you.