How to Replace a Leaky Toilet Water Shutoff Valve – Part 3

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How to Replace a Leaky Toilet Water Shutoff Valve – clean the copper water supply tube and install the new 1/4 turn shutoff valve. This project is continued from How to Replace a Leaky Toilet Water Shutoff Valve – Part 2.

This is the 1/2 inch cold water copper pipe in the bathroom floor after removing the old water shutoff valve. The oxidation and build-up of minerals must be cleaned before the new 1/4 stop valve is installed:

Toilet Water Stop Valve Installation: 1/2 inch Copper Pipe Stub

Toilet Water Stop Valve Installation: 1/2 inch Copper Pipe Stub

The Oatey 4-in-1 brush does a great job of cleaning the copper pipe stub. Just wiggle and rotate the brush back and forth on the pipe:

Water Stop Valve Installation: Clean the Pipe Stub with Oatey 4-in-1 Brush

Water Stop Valve Installation: Clean the Pipe Stub with Oatey 4-in-1 Brush

Bathroom Water Shutoff Valve Installation

The new Brasscraft 1/4 Stop Valve, compression nut and brass sleeve are ready for installation on the cleaned 1/2 inch copper pipe. Notice the deep pocket in the stop valve to receive the pipe stub:

1/4 Turn Water Stop Valve Installation: New Valve and Cleaned Pipe

1/4 Turn Water Stop Valve Installation: New Valve and Cleaned Pipe

Slide the compression nut over the pipe stub with the threads facing the end of the pipe followed by the brass compression ring:

Water Stop Valve Installation: Compression Nut and Brass Sleeve

Water Stop Valve Installation: Compression Nut and Brass Sleeve

Set the stop valve body on the end of the copper pipe and press until the valve is fully seated. Rotate the valve body so the valve handle is easy to reach:

Brasscraft 1/4 Water Stop Valve Installation

Brasscraft 1/4 Water Stop Valve Installation

Tighten the compression nut on the stop valve by hand. Then place a wrench on the valve body to hold it steady and tighten the compression nut with a second wrench. Tighten the nut a 1/2 turn after you feel it seat or bite against the brass sleeve. Do not over tighten the nut to avoid cracking the valve body or nut. You can always tighten the nut slightly if there’s a water leak:

Bathroom Water Stop Valve Installation: Tighten the Compression Nut

Bathroom Water Stop Valve Installation: Tighten the Compression Nut

The new water shutoff valve is installed on the 1/2 copper pipe. Almost done!

Water Stop Valve Installed on 1/2 inch Copper Pipe

Water Stop Valve Installed on 1/2 inch Copper Pipe

I really like the steel braided Brasscraft Speedi Plumb PLUS Toilet Connector hose which has a 3/8 inch compression nut and o-ring built into the hose. Unscrew the 3/8 inch compression nut included with the new stop valve. Set the valve nut and brass sleeve aside. Note: You may need these if your toilet connector hose is different!

Water Stop Valve and Brasscraft Speedi Plumb PLUS Toilet Connector

Water Stop Valve and Brasscraft Speedi Plumb PLUS Toilet Connector

Attach the toilet connector hose to the stop valve and tighten with a wrench. Do not over tighten.

Water Stop Valve: Attach the Toilet Connector Hose

Water Stop Valve: Attach the Toilet Connector Hose

View of the new 1/4 turn toilet water stop valve and connector hose. Time to turn on the water at the water meter and check for leaks.

Water Stop Valve Replacement and Toilet Connector Hose

Water Stop Valve Replacement and Toilet Connector Hose

Turn on the Water and Check for Leaks

Turn On the water at the water meter. Wait for the air in the pipes to clear and close the faucets that were opened previously to drain the house water pipes.

Turn On the water stop valve to refill the toilet tank. Check the valve connections for leaks. Tighten the compression nuts a 1/4 turn if you find a leak. Toilet paper is an excellent tell-tale for finding small and slow leaks because wet spots show very well.

Water Stop Valve Replacement: Leak Check

Water Stop Valve Replacement: Leak Check

Hope this helps,

Bob Jackson

Copyright © 2018   Reproduction strictly prohibited.


  1. Chris February 12, 2013 at 12:40 am - Reply

    I followed this guide and it worked perfectly. However, I now have a small leak coming from the point where the brass meets the fitting. It is like 1-2 drops per hour. Any suggestions on how to fix it. I don’t want to over tighten.

    • BobJackson February 12, 2013 at 7:46 am - Reply

      You’re certain the leak is coming from the stop valve compression fitting and not the toilet connector hose fitting?

      If the leak is at the stop valve, use two wrenches to tighten the stop valve compression fitting. The purpose of the soft brass compression sleeve is to deform and squeeze against the copper pipe, compression nut and valve body to make a water tight seal. Another 1/4 turn or so should do it. Recheck for leaks and if necessary, tighten it 1/8 turn. If you feel the compression nut is very tight and would take significant effort to tighten more, stop, turn off the house water supply, remove the stop valve and install a new valve. Check the copper pipe stub for debris and clean again if needed. When installing the new valve, make sure the valve body seated all the way on the copper pipe stub until the pipe bottoms out in the valve body. Always thread the compression nut by hand onto valve body until snug before using the wrenches.

  2. Greg Klinker July 11, 2014 at 11:43 pm - Reply

    Thank you! Thank you! Thank you! I was lost before I found your instructions, being handy work challenged. You provided clear, understandable dialog and very useful photos. The job went well and was successful. Thank you again!

  3. james sims February 15, 2016 at 10:31 am - Reply

    my supply line is not copper but chrome does the same inst apply?also my line comes from the wall not the floor and my toilet line is on the top.

    • Bob Jackson February 15, 2016 at 6:37 pm - Reply

      You have an chrome-plated copper toilet water supply line for a nice look!

      The replacement steps may be different depending if the stop valve is a threaded or compression connection. You can tell the connection type by:
      * Compression: The valve will have a compression nut between it and the wall, matching the project as shown.
      * Threaded: You should be able to see an exposed pipe thread or two on the wall-side of the valve and it will not have a compression nut.

      For example, this Kohler K-7637-CP (CP means Chrome-Plated) supply line includes the stop valve. The Kohler K-7637-CP Installation Instructions show the valve is threaded onto the chrome supply pipe.

      BTW, chrome-plated pipe and stop valves are never sweat (solder) joint connections because the solder wouldn’t hold and the torch flame will ruin the chrome finish.

  4. Karen March 1, 2016 at 12:30 pm - Reply

    Hello Bob,

    Great instructions, thank you!

    I see you have replied to this recently, so I’m hoping this is still an active thread. I have been having a heckuva time plumbing my antique clawfoot tub. I bought chrome offset water supply lines – which are exposed. I have copper source pipes coming up through the floor. When the job is done, I don’t want to see any copper. After much research, I was finally able to find compression shut-off valves that are 1/2 inch to 1/2 inch O.D. to connect my copper pipes to my chrome risers. I have chrome sleeves to fit over top of the copper pipes (end stubs).

    What I need to know is exactly how much copper pipe I need to leave above the sleeve to allow for the compression valve to fit snugly against the chrome sleeve – so that there isn’t any space between the sleeve and the compression nut exposing the copper beneath. The valves came with no installation instructions or specs. Is there a way to do a test without ruining the brass ring inside or is there perhaps a standards measurement?

    Thank you kindly,

    • Bob Jackson March 1, 2016 at 6:41 pm - Reply

      Have you considered cutting the pipe stubs a little long and covering the exposed copper pipe between the floor surface and stop valve with chrome escutcheons?

      There are two ways to determine the length of copper pipe needed to fully seat the valve:

      Test Fit:
      Buy a short piece of 1/2 inch copper pipe at the home improvement store and assemble the shut-off valve hand-tight only. Mark a pencil line on the exposed pipe at the valve, remove the valve and measure the distance from the end of the pipe to the pencil mark. This is the length of the water supply pipe stub needed above the floor. If you decide include an escutcheon, add the thickness of the escutcheon plus another 1/8 inch to the pipe stub length. The extra 1/8 inch is for a margin of error. Home Depot and Lowes sell 1/2″ x 2ft copper pipe sections for about $5.

      BTW – I had a similar pipe-fitting problem when I replaced an in-line shutoff valve but with less margin for error. See Measure and Fit the SharkBite Ball Valve in this project.

      Fast & Close Enough:
      Screw the nut and brass ring on the stop valve hand-tight. Insert a tape measure in the valve opening such that it rests against the inside shoulder where the end of the copper pipe will be fully seated. Measure the distance from the shoulder to the outside face of the valve nut. This is the required length of the water supply pipe stub. Again, if using an escutcheon add it’s thickness plus another 1/8 inch to be conservative.

    • Jim in Michigan July 18, 2016 at 8:55 am - Reply

      KAREN and others,
      Karen has probably finished her claw foot tub installation, however, general GOOD ADVICE:
      IF there is no EASY access to the hidden end of the water pipes coming thru the floor/wall to the valves, the danger of Karen wanting to cut the stub for the shutoff valve to a minimum length (for a nicer appearance) is the possibility that the stub could be damaged (now or future) and the stub would then be too SHORT to install a new valve, and the TUB and FLOOR would have to be REMOVED to repair (EXTEND) the pipe to make it long enough to replace the valve. (Big risk for nicer appearance.)
      I would have left the stub at least 2 inches more than the minimum, and covered the copper below the valve with silver foil tape (looks like chrome), plus escutcheon.
      From the valve, to the faucet, I would have used the flexible tubing with stainless steel braid (looks like chrome, see the picture above “Water Stop Valve Replacement and Toilet Connector Hose”). The stainless steel braid hoses fit the same valves, and have a rubber seal in each end that is much easier, and more reliable to use, than the “compression” method.

  5. Karen March 1, 2016 at 9:49 pm - Reply

    Wow, thank you! You are a real gem! I really appreciate your ability to give clear and concise explanation’s that are so accessible.

    Sorry, I did forget to mention that, yes, I am using an escutcheon at the bottom. However it won’t affect the measurement of the exposed copper because the chrome sleeve that slides over the copper stub rests at the top of the escutcheon ~ it does not fit into the hole in the escutcheon (I hope that makes sense). However, I will of course take its height into account for the overall measurement.

    Anyway, I got exactly what I needed from your explanation – this being only my second ever DIY plumbing job and first time with a compression fitting, I wasn’t sure if you could do a trial run with the nut or if that would ruin the brass ring inside and make it unusable.

    Karen ?

  6. Joe July 16, 2016 at 2:16 am - Reply

    Hello Bob,
    Thank you very much for very helpful instructions. I hope I can ask a fridge supply line question here as this question is closest to my issue. I’m getting a new fridge and the store says they won’t install it unless I have a shut-off valve behind the fridge. What I have for the old fridge is a 10′ run of 1/4″ soft copper that goes from under the sink (where it taps into the sink’s cold supply with a saddle T puncture-type fitting), through the crawl space and up through the floor behind the fridge. There is about 10′ of extra copper coiled up behind the fridge that allows the fridge to be moved.
    They say they don’t like this setup because of the saddle-T connection under the fridge and the long coil of copper behind the fridge which they say is prone to kinking and leaking if you move the fridge. Instead they suggest installing a shutoff valve behind the fridge and if we have that they will connect a 10′ flexible stainless supply line from the shutoff to the fridge.
    Are they right that my setup is not very good? If I do as they suggest do I need to run new 1/2″ from the sink to behind the fridge, or can I leave the 1/4″ copper in place and just change the fitting under the sink to a standard T fitting? Behind the fridge should I cut off the excess coiled copper in order to put in a 1/4″ x 1/4″ shutoff valve, and let them connect their stainless supply tube to it? Can I even put a 1/4″ shutoff there on soft copper?
    Our current setup has been trouble free for about 20 years with no leaks, but if it’s not up to modern standards, we’ll update it. Thank you for your advice.

    • Bob Jackson July 16, 2016 at 2:32 pm - Reply

      I concur with the appliance store and their advice. My former home had a setup like yours and I was always concerned about causing a leak when moving the refrigerator.

      Replace the 1/4 inch soft copper tube and saddle valve with a run of 1/2 inch copper pipe to a recessed ice maker box in the wall behind the refrigerator.

      The SharkBite 1/2″ Ice Maker Box should work well. SharkBite push-fit fittings are easy to use and requires no soldering.

      Refrigerator/Ice Maker Box Installation Steps:

      • 1 – Shutoff the water supply to the house at the water meter.
      • 2 – Open the upstairs and kitchen faucets to relieve the water pressure and drain the lines.
      • 3 – Remove the saddle valve, measure and cut out a short section the copper pipe to install a SharkBite repair coupling.
      • 4 – Working in the crawlspace, cut the cold water copper pipe and install a SharkBite Tee fitting. It’s so much easier to tap the cold water line in the crawlspace versus drilling holes in the sink cabinet and subfloor to run new pipe from the sink to the crawlspace.
      • 5 – Locate the wall studs behind the refrigerator, measure and cut an opening for the SharkBite Ice Maker Box. The box can be used for “old work” installations by cutting the drywall over the 2×4 stud to expose the mounting ears. The box trim plate will cover the ears.
      • 6 – Run the new 1/2 inch copper pipe from a SharkBite Tee under the floor joists and up through wall sole plate behind the refrigerator. You may have to drill a 5/8 inch hole to run the pipe up and into the wall cavity.
      • 7 – Measure and cut a 2nd opening in the drywall about 5 inches below the ice maker wall box. Size this opening to fit a small drywall access panel. You need this to reach inside to connect and/or disconnect the SharkBite Ice Maker valve inside the wall. I recommend installing SharkBite fittings only in accessible areas.
      • 8 – Install the ice maker box by completing the pipe connections, fasten the box ears with two pan head wood screws, install the trim plate, connect the plastic water line to the refrigerator.
      • 9 – Turn On the valve at the water meter and check for leaks.
      • 10 – Install the cover on the drywall access panel below the ice maker wall box.
      • SharkBite Ice Maker Box and plumbing fittings are available at Home Depot and


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