How to Replace a Shutoff Valve

Stop under-sink leaks with this 30-minute fix.

Next Project

A full day




Less than $20


You can spend time rebuilding the old valve, but the problems will just reappear years from now. The best way to deal with bad valves is to replace them with modern quarter-turn ball valves. They rarely lock up, leak or wear out and best of all, they'll take just an hour or so to install. Here's how to put them in.

Tools Required

  • Adjustable wrench
  • Flame-protecting cloth gloves
  • Locking pliers
  • Soldering torch

Materials Required

  • Shutoff valve

Identify the valve connection style

A shutoff valve connects to copper plumbing pipes in one of two ways:

  • Compression fitting
  • Sweat fitting.

Identify the connection type used in your home by referring to the photos below.

If you have an older home with galvanized pipes, we suggest hiring a plumber to do the switch out. Unscrewing the old valve and screwing on a new one may seem easy enough. But if the pipe is rusted internally or the threads are rotted, this ‘simple’ plumbing job can turn into a plumbing nightmare. If your home is plumbed with PEX or plastic pipe, these instructions don’t apply.

Once you identify the connection type, buy a quarter-turn shutoff ball valve to match the size of the incoming copper pipe and the size of the supply tube connection. If you’re replacing a sweat valve, you’ll need a torch, flux, solder, emery cloth, wire brushes and a flame protection cloth to shield the wall. This is also a good time to replace an old supply tube and a corroded escutcheon (wall trim plate). Sorry to burst your bubble, but you need to stop believing these 10 plumbing myths ASAP!

Project step-by-step (12)

Step 1

Sweat Valve:

sweat valveFamily Handyman

A sweat shutoff valve doesn’t have any hex flats where the copper tubing enters from the wall. Replace a sweat valve with another sweat valve or a compression valve.

Step 2

Compression Valve:

compression valveFamily Handyman

Examine the portion of the valve closest to the wall. Look for a hexagonal compression nut and matching hex flats on the body of the valve next to the compression nut. If the valve has a compression nut but no hex flats, look for two flats on the sides of the valve body.