Replacing a Fixture Shut-Off Valve
Updated February 20, 2026
Fixture shut-off valves are one of those things you never think about until they don't work. You go to shut off the water for a faucet repair, crank the handle, and... nothing. The old multi-turn gate valve is seized, corroded, or it just spins without closing. Swapping it for a quarter-turn ball valve is a $10 fix that takes 30 minutes, and it's one of the smartest preventive upgrades you can make anywhere in the house.
Overview
Fixture shut-off valves are one of those things you never think about until they don't work. You go to shut off the water for a faucet repair, crank the handle, and... nothing. The old multi-turn gate valve is seized, corroded, or it just spins without closing. Swapping it for a quarter-turn ball valve is a $10 fix that takes 30 minutes, and it's one of the smartest preventive upgrades you can make anywhere in the house.
What to Know
Tools & Materials
- Two adjustable wrenches
- Mini tube cutter
- Bucket and towels
- Quarter-turn ball valve (correct size and connection type)
- Emery cloth
- Thread seal tape (for threaded connections)
Step by Step
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Shut off the main water
You're replacing the local shutoff, so it can't help you. Turn off the main water supply. Open a faucet on a lower floor to relieve pressure. Place a bucket under the valve -- there will be residual water.
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Remove the old valve
Disconnect the supply line from the valve outlet. Then remove the valve from the supply tube. For compression: hold the tube steady with one wrench and turn the valve nut with the other. For threaded: unscrew counterclockwise.
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Prep the tube
If reusing the same compression ferrule isn't possible (the old ferrule is usually stuck), cut the tube below the ferrule with a mini tube cutter to get a fresh surface. Clean the cut end with emery cloth until bright.
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Install the new valve
Slide the new compression nut and ferrule onto the tube. Thread the valve body on and hand-tighten. Hold the valve body with one wrench, tighten the compression nut with the other -- one full turn past hand-tight.
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Reconnect and test
Reattach the supply line to the valve outlet. Turn the main water back on slowly. Open the new valve. Check every connection for drips with a dry paper towel.
Pro Tips
- Replace shutoff valves in pairs. If one is old and corroded, the one next to it is just as bad.
- A mini tube cutter is essential for the tight space behind toilets and under sinks -- a full-size cutter won't fit.
- While you're at it, replace the supply line too. Braided stainless steel lines are $5-$8 each and far more reliable than old plastic or chrome lines.
Mistakes to Avoid
- Not turning off the main water first -- the whole point is the local valve doesn't work.
- Overtightening the compression nut. One turn past hand-tight. More force deforms the ferrule and causes leaks.
- Reusing an old ferrule that's been deformed by the previous compression.
- Buying the wrong valve size -- measure the tube outer diameter first.
When to Call a Pro
If the supply tube coming out of the wall is galvanized or severely corroded, or if the main water shutoff won't close either, call a plumber. You need a working main shutoff before you can replace any fixture valve.
Bottom Line
A $10 ball valve and 30 minutes of work gives you a reliable shutoff for years. Do this at every fixture in the house over a weekend and you'll never be caught without a working shutoff again.