Fix-It Friday: How To Replace A Water Shutoff Valve

under sink valve
Fix-It FridayHome Improvement 1 Comment

I just watched a big-box TV commercial showing a mom and daughter replacing their bathroom vanity. They make it look so easy, too easy, in fact, as if they’re changing out a comforter set and throw pillows! Now of course a mom and daughter can do a project like this one, but don’t present it in a way that’s misleading in its degree of difficulty, because if you do, you’re setting folks up for failure. Let me give you an example…

Ok, you’re all excited to start your plumbing project, replacing your vanity! Step 1. Turn off the water from the shutoff valve. Easy enough. Wait a minute, the shutoff valve is leaking like a sieve! Now what am I supposed to do? Or what if the valve handle won’t turn at all cause it’s old and seized in the open position?

Both scenarios are very common problems when replacing an old faucet, sink, or toilet.

So now, my dears, the first phase of your vanity project becomes Replace a Shutoff Valve…which means you’ll have to be prepared to have the all the water in your house shutdown for several hours. You’ll never get a glimpse of that kind of heads up in a TV spot!

The good Lord knows I’m never about discouraging folks from attempting projects, I just want people to make informed decisions about what projects to choose and what challenges they may face.

So without further ado, here’s how to replace a water shutoff valve.


The Tools

  • Adjustable wrench
  • Tongue and groove pliers
  • Flashlight
  • Hacksaw, PVC cutter, or pipe cutter
  • Sandpaper or steel-wool and rags
  • Plumber’s phone number – just in case!

The How To

  1. To get started, turn the water supply to the house off. (Your water main shutoff should be in your garage or basement. Locate this first and label it if it isn’t already).
  2. Now back to the sink (or toilet… same fix applies to both). Take a look at the fitting below the shutoff valve. It will either be a soldered connection, a screwed on fitting, or a compression fitting. To determine the exact replacement, you will need to remove the old valve and bring it to your hardware or plumbing store to determine the right size and type of valve.
  3. Unscrew and disconnect your supply line(s).
  4. If your valve screws on: Unscrew it with an adjustable wrench. Screw the replacement valve on, and skip to step 11. If your valve is soldered on: Cut the pipe just below the existing valve. You can use a hacksaw, a PVC cutter, or pipe cutter as appropriate. Try to make the cut straight across the pipe. Don’t cut it too close to the wall or you won’t be able to install the new valve! With a new pipe tip you’ll be ready to install a compression fitting -no soldering necessary. If your valve is a compression fitting: It will look like it can be unscrewed. Twist the nut with an adjustable wrench, while holding the pipe stub the valve is attached to with another wrench (so you don’t yank and damage any connection behind the wall or distort the round of the pipe). Twist and pull the old fitting off. There may be a compression ring left on the pipe. Slide it off. If the ring is metal and really stuck on there, just leave it there for your new valve to fit over. If there is enough pipe exposed, you could also simply cut the valve off and start from scratch.
  5. shutoff valveTake the pieces to the hardware or plumbing store to ensure that you buy a valve that fits the pipe diameter for your project.
  6. To install your new compression fitting, first clean the end of the pipe where the valve will fit with sand paper or steel wool.
  7. Slide the compression nut over the water line.
  8. Slide the compression ring over the water line (unless using the old one – see step 2 for compression fittings).
  9. Slide the new valve over the water line. Position the handle for easy access.
  10. Tighten the compression nut against the valve. Use an adjustable wrench to snug this connection. If your plumbing supplier recommends it, use a little pipe joint compound on the threads.
  11. Install the supply line(s) connecting the valve(s) to the faucet(s).
  12. Turn the water back on at the main and check the new valves for leaks. If you see any seepage, tighten the connection a little more. If this doesn’t solve the problem, turn the water back off and examine the fitting for damage.

On a final note, don’t let the magic of television (or retailers’ drive for sales) delude your sense of reality. Always check a project’s degree of difficulty before getting started. Here, for example, changing out a vanity would be intermediate to advanced, replacing a shutoff valve, basic to intermediate, depending on the type of shutoff.

All this talk about shutoff valves… if only I could replace my shutoff valve, the one that controls my menstrual flow, because apparently it’s broken in the open floodgate position. Menstrual plumbing degree of difficulty: impossible.

Norma sig

Lead image credit: BrassCraft

Got A DIY Question? Ask-The-Expert!

If you have a DIY home repair, maintenance or improvement question for Norma, now is your chance to ask-the-expert and have her answer. Your burning question may just be the “star” of an upcoming Fix-It Friday column.

Add your question to the comments section below or email it to Women You Should Know.

Fix-It Friday is an exclusive Women You Should Know® editorial series authored by seasoned veteran of home improvement, Norma Vally, the former host of Discovery Home Channel’s series “Toolbelt Diva” and a show on Sirius Satellite Radio by the same name. The weekly column is designed to inspire women – weekend warriors, aspiring handywomen, and even seasoned DIYers – to take on home repairs and maintenance projects with confidence and gusto.


  • Lisa

    So I am replacing my bathroom sink. Got it off ok and now am installing shut off valves. The guy at the hardware store showed me which one to buy. All going ok except… I cut off the soldered on connection as per normal. Cleaned the pipe with steel wool and slid on the nut and compression ring. Pushed it into position and hand tightened the nut. Just one problem. I can slip the valve off the pipe. It is ever so slightly loose. And I mean ever so slightly. Looks like the right size. Am I missing something here? Don’t want to tighten with a wrench just yet so I can return the valve if need be. Should tightening nut with a wrench result in the nut becoming solidly in place and preventing it from slipping off? When you look at it together off the pipe the ring and nut look smooth as though one cylinder. Does tightening with a wrench crimp the nut making it bulge thus tightening around the pipe to prevent it from being pulled off? Help. My water is shut off making my family miserable at me until I solve this and am able to turn the water back on.