I am trying to replace an old faucet that my 3 yo child is unable to use because of its design. I'm new to plumbing but actively reading. I haven't seen these supply lines w/o valves before. This looks like the pipes are going straight into the faucet. This is an '86 built property in Canada. I tried to look through the vanity base but didn't find a valve.

Its a fatter pipe which gets slimmer as it enters the faucet.

  1. Ideally I would like to add valves and then modern braided pipes into a new simple faucet. Is this doable and wise?
  2. What tools will I need to achieve this - I have a wrench, channel locks and the basics. I think I'll need a pipe cutter and something to smooth out the freshly cut pipe. Any solution/paste?
  3. What hardware will I need to purchase - if it's a 1/2" pipe, can I use any straight 1/2" valve?
  4. Is a modern faucet built to the same standard that modern valves and pipes are built to?
  5. How can I make a secure seal w/o using a soldering solution? I read this is where compression valves come in.

Pic of work area:

cabinet area under the sink

Pic of faucet inside:

under side of faucet with trim piece removed

Pic of view from under sink:

lines feeding up through sink deck

  • 1
    What's directly below this bathroom? Is there a basement/crawlspace? If so, there may be a shutoff for the hot & cold down there. It's less convenient when replacing the faucet, but it made installing the vanity easier because only a small hole to clear the pipe was necessary, not a big hole to clear the pipe & shutoff.
    – FreeMan
    Feb 23, 2022 at 12:58
  • 1
    I purchased this SharkBite faucet installation kit when preparing to replace the vanity/sink/faucet in my main bathroom. Couldn't have been easier. Just cut the old pipes and push the shutoff valves on. Feb 23, 2022 at 16:34
  • @FreeMan There is a kitchen under this bathroom, unfortunately no crawl space. I just moved here less than a month ago and gradually making discoveries. Thanks for editing the topic title, took me back to my GMAT days.
    – eszed
    Feb 23, 2022 at 17:20
  • Wow... That seems to be an expensive kit to do either the hot or cold side, @MichaelMior. And, it doesn't come with a pipe cutter that the OP will need. But it comes with far more PEX than would be needed for both sides combined. I mean, if it worked for you, great, but I'm not sure this is the best option.
    – FreeMan
    Feb 23, 2022 at 17:27
  • 1
    That's possible, @MichaelMior. I looked at the image description showing (1) of everything. Still no tubing cutter nor PEX cutter (those can be pricey) that the OP will need. If that does include 2 of everything it otherwise looks like it might be a fair deal.
    – FreeMan
    Feb 23, 2022 at 18:11

3 Answers 3


This isn't a very difficult job for a new diyer to tackle. You'll only need some basic tools in addition to a pipe cutter and deburring tool. Here is what needs to be done:

Installing the Shutoff Valves
I suggest that after you turn off the water at your main, make sure the water is off by opening the hot and cold faucets at the sink. Use a pipe cutter to cut both of the standpipe supply lines coming up through the bottom of the cabinet. Keep as much height as you can by cutting them directly below the soldered connection before the connection to the narrower tubes. Remove the old faucet. From the pics looks like a wrench will do it from under the cabinet.
Use a copper deburring tool to remove any copper burrs in the cut area. Use some fine steel wool to clean the exterior of the top two inches of copper.
Purchase two 1/4 turn straight shutoff valves with a 1/2" compression fitting on the inlet side and a 3/8" compression fitting on the outlet side as shown.
enter image description here
Follow the directions by sliding the 1/2" nut over the standpipe followed by the compression ring provided. Then slide the 1/2" end of the valve over the cleaned copper pipe. Make sure the valve is fully seated down onto the pipe. Thread the nut up onto the bottom of the valve by hand and then tighten it with an adjustable wrench. Use a second wrench on the body of the valve to stabilize it so you don't torque the copper pipe while you tighten the nut. It needs to be tightened enough to compress the brass compression ring - so good and tight.
Perform the same procedure on the other stand pipe. Make sure that both valves are closed with the valve handle pointing 90 degrees away from the pipe.
Turn on the main slowly and check for any leaks/seepage around the fitting.

You should be fine but as a novice you might want to have another person at the main in cell phone contact with you in case you need them to shut down the main quickly.

Installing the Supply lines and Faucet
Your sink has three holes precut. Make sure that the faucet you buy will accomodate that setup. Most faucets will have braided supply lines with the faucet. You'll want to measure to make sure the length will reach from the shutoffs you installed to the faucet connections.
Install the faucet according to the instructions attaching the braided supply lines to the outlet side of the shutoff valves. When using braided lines you won't need the compression nut on the outlet side of the valve. The braided line coupling will thread directly onto the outlet.
You can also tune in to a YouTube video which might increase your comfort level but take your time and it shouldn't be a problem.
Good Luck!

  • Instead of fine steel wool, I find green scotchbrite is much better for cleaning copper.
    – Solar Mike
    Feb 23, 2022 at 15:54
  • I've used a metal file as well. If you're using a scoring cutter, deburring isn't hard at all.
    – Machavity
    Feb 23, 2022 at 17:25
  • 1
    @eszed - You can use sharkbites but they're more expensive and there's no upside. Sharkbites are good if you don't want to sweat on a fitting. A compression nut installs easily and there's no need for any soldering.
    – HoneyDo
    Feb 23, 2022 at 17:50
  • 2
    @J - All true. Read my entire comment. In OPs circumstance the compression fitting is the way to go.
    – HoneyDo
    Feb 23, 2022 at 19:15
  • 6
    Use ball (¼ turn) valves. They hold up much better over the long run.
    – Llaves
    Feb 24, 2022 at 4:58

HoneyDo has a great answer; I'm putting extended comments here with some photos of one of my bathroom sinks with a new faucet installed last year.

I would just note that I like to spend extra and buy quality shut-off valves with real metal construction, not e.g. plastic knob shafts that can snap off. The supply lines should be good quality stainless-steel braided, not plastic braided. In my area of the US, bathroom faucets often come without supply lines, and often have 2 combination supply/mounting outer threaded pipes coming down from the ends of the bottom. Outer nuts run up the threads to clamp the faucet to the underside of the sink surround, then the supply lines thread onto the bottom ends of the pipes with an O-ring seal.

Re: faucet connection. The faucet type will likely be "centerset" with the outer mounting/water supply pipes 4" apart. They will likely accept a 1/2" IPS (Iron Pipe Standard) connection to the braided supply line. Thus, the stainless steel braided supply lines should be 1/2" IPS to 3/8" compression, but the actual connectors will have rubber gaskets inside making the seal. I tighten them finger tight, then use a wrench to tighten an additional 2/3 turn. It's important not to overtighten, as that distorts the O-ring and causes leaks.

Real plumbers use "basin wrenches" to turn nuts on the underside of the mounting area, but I've found the cheap-looking plastic faucet installation "wrenches" sold at big box stores easier to use for me (see bottom photo for example only). You can slide the side opening over an attached supply line or protruding pipe and tighten plastic or metal nuts, depending on the tool/insert orientation.

UndesideOfSinkShowingFaucetConnections1_2InchIPS WaterSupplyLineConnectedTo3_8AtShutoffValve PlasticFaucetWrench

  • 3
    Good additional info. I'd suggest actually attaching the braided lines to the faucet before attaching the faucet to the sink. That's two fewer connections that have to be made while lying awkwardly inside the cabinet working over your head in a cramped space. Also, if the braided lines are too long, simply make a loop with them to shorten them. The line will not bend tighter than its approved minimum radius (unless you kink it, then you've likely ruined it or at a minimum shut off your water supply with an impromptu valve).
    – FreeMan
    Feb 23, 2022 at 13:00
  • 1
    @FreeMan A disadvantage of this type of combination water/mounting pipes on the faucet assembly is that you can't attach the supply lines before installing the faucet :( . The white plastic mounting nuts can only be threaded on after the pipes come down through the holes, and the supply line nuts can only be threaded on after the white mounting nuts go on that outside threading.
    – Armand
    Feb 23, 2022 at 15:41
  • 1
    Ah, that makes it difficult. However, not all faucets mount this way.
    – FreeMan
    Feb 23, 2022 at 15:45
  • Thanks for the additional info. Believe it or not, one birthday my mother-in-law gifted me the red under-sink wrench you've referrenced with a pic. I just found it sealed brand new. Good brand too - Rigid. I had no use of it until now. The bathroom in question has 2 sinks (in the same condition as my post) so the hunt for a matching set continues. Will update this thread asap.
    – eszed
    Feb 25, 2022 at 17:56

Update 3/10. Adding here due to size.

I've completed both sinks and the faucets and drains are functioning fine.

  1. I used Sharkbite fittings instead of a compression valve as thats all HD had at the time. Since this was time sensitive I went with a pair. Otherwise I followed HoneyDo's steps. I marked 0.95" to ensure the fittings were pushed all the way.

  2. I made a very clean and careful cut using the pipe cutter. After running my fingers around it (inner and outer) I did not feel sharp edges. However I still used a deburring tool (1.5-2 turns) and it was smooth,

  3. I cut the pipe at its smoothest point where there was no solder residue. Felt uncomfortable using a steel wool pad or Scotch Brite pad as I felt it would make the pipe "thinner" therefore increasing leak risk. But all guides advised to use it so I did sparingly.

  4. Is this level of bend/flex in the supply pipes OK?

  5. The faucet had soft copper pipes which were annoying to work with. I felt they would break any second but I was as careful as I could be.

enter image description here enter image description here

Here is the 2nd faucet that I shared in the original post. This marks the project complete. enter image description here

  • 1
    Looks good - the flex in the supply lines is fine.
    – Armand
    Mar 11, 2022 at 5:27
  • 1
    Leaving the labels on the hoses may look shoddy, but it's a huge convenience to the next person who may have to replace parts under here since the threading is indicated on the labels. Makes life much easier, and future you will appreciate it!
    – FreeMan
    Mar 11, 2022 at 17:10
  • Soft copper will bend a lot before it will break. That's the point of it being soft. It can be adjusted to any convenient position. Just don't kink it (make a very sharp bend.)
    – Ecnerwal
    Mar 11, 2022 at 17:23
  • 2
    The 2nd faucet took 1/3rd the time. This was my first plumbing DIY and I enjoyed it - more so because this was for my child that can now easily use the faucet. I placed leak detectors under each sink and one went off the next day, turns out the faucet escutcheon was not aligned which I quickly fixed. Is it normal to stop and stare at your first DIY every few hours? Thanks for the responses everyone.
    – eszed
    Mar 12, 2022 at 4:13

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