Can I replace a shut-off valve myself?

Yes, if it is a compression or push-fit valve on copper or PEX pipe — that is a genuine 30-minute DIY job with hand tools, no soldering. You shut off the main water, drain the line, remove the old valve, and slide on a new compression or push-fit quarter-turn valve. Where it stops being DIY is a valve that is soldered (sweated) onto copper, or one on old galvanized steel pipe: removing a soldered valve means a torch and open flame near cabinet walls, and galvanized pipe often crumbles, both of which are better handed to a plumber.

What is the difference between compression and push-fit valves?

A compression valve seals by tightening a nut that squeezes a brass ferring (ring) onto the pipe — reliable, cheap and the traditional choice, but it needs the pipe to be clean and round. A push-fit valve (like SharkBite) simply pushes onto the pipe end and grips with internal teeth and an O-ring — faster, tool-free, and forgiving, but pricier. Both work on copper; push-fit also works on PEX and CPVC. For a first-timer replacing an under-sink stop, a push-fit quarter-turn valve is the easiest and most reliable choice.

Should I replace a multi-turn valve with a quarter-turn valve?

Yes, whenever you have the chance. Old multi-turn (gate or globe) stop valves are the ones that seize, weep at the stem, and fail to fully close just when you need them in an emergency. A quarter-turn ball valve turns 90 degrees from fully open to fully closed, almost never seizes, and gives a clear on/off. Since you have the water off and the line open, upgrading is a small extra step that pays off the next time you need a fast, reliable shut-off for a repair.

How tight should a compression valve nut be?

Hand-tight, then about one full turn past that with a wrench — roughly a turn to a turn and a quarter is the common guidance, but tighten just until the joint is snug and does not leak under pressure. Overtightening a compression nut deforms the brass ferring and can actually cause a leak or crack the nut. Turn the water on and check; if it weeps, give it a small additional nudge rather than cranking hard. Hold the valve body steady with a second wrench so you do not twist the pipe.

Do I need to turn off the main water to replace a shut-off valve?

Yes — because you are removing the very valve that isolates that fixture, you must shut off the water upstream, which usually means the main water shut-off for the house (or a branch shut-off if you have one). Then open the fixture's faucet and a lower faucet in the house to drain the lines down. There will still be residual water in the pipe, so keep a bucket and towels ready. Never attempt this with the main on — you will get the full house pressure the moment the old valve comes off.

How to Replace a Water Shut-Off Valve Under a Sink

Written & researched by Priya Anand DIY & Tools Editor

Updated August 2026

Three-quarter view of a person's hands tightening a fitting under a kitchen sink with a wrench, in warm late-afternoon light

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Replacing an under-sink shut-off valve is a DIY job on copper or PEX — about 30 minutes, $8 to $20 for the valve, no permit — as long as the old valve is compression or push-fit, not soldered. You shut off the main, drain the line, remove the old valve, and fit a new quarter-turn compression or push-fit valve. Push-fit valves need no tools and are the easiest choice. The job crosses into plumber territory when the existing valve is sweated (soldered) onto copper or sits on old galvanized steel pipe that may crumble.

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How To Remove and Install a Shut-Off Valve — Got2Learn

First, identify the valve and pipe type

Look at how the old valve attaches. A compression valve has a nut and a small brass ring where it meets the copper pipe. A soldered valve is fused directly to the copper with no nut — that one needs a plumber or a torch. Check the pipe too: bright copper or flexible PEX is DIY-friendly; dull grey galvanized steel with threaded fittings is old and often too corroded to work safely without a plumber.

Wide view of a person's hands tightening a fitting under a kitchen sink with a wrench, in soft overcast light

Tools and materials

A new quarter-turn shut-off valve — push-fit for the easiest install, or compression.
Two adjustable wrenches (to hold the valve and turn the nut), a tubing cutter (if trimming copper), and a deburring tool.
A bucket, towels, and a rag. Basic hand tools — see best plumbing tools.

Step 1: Shut off the main and drain

Close the main water shut-off for the house (or the branch that feeds this fixture). Open the fixture's faucet and a faucet lower in the house to drain the lines. Keep a bucket under the valve — residual water remains in the pipe. Confirm the flow has stopped before you touch the old valve.

Overhead view of a person's hands tightening a fitting under a kitchen sink with a wrench, in warm late-afternoon light

Step 2: Remove the old valve

For a compression valve, hold the valve body with one wrench and loosen the compression nut with another, then slide the valve and the old ferring off the pipe (a puller or a careful cut helps if the ring is stuck). For a push-fit valve, use the release tool. Wipe the pipe end clean. If the pipe end is damaged, cut it back square with a tubing cutter and deburr the inside and outside edges — a burr will nick the O-ring on a push-fit valve.

Step 3: Install the new valve

For a push-fit valve, mark the insertion depth on the pipe, then push the valve straight on until it bottoms out at that mark — that is the entire install. For a compression valve, slide the new nut and ferring onto the pipe, seat the valve, and tighten the nut hand-tight, then about one full turn past with a wrench while holding the valve steady. Point the valve outlet toward where the supply line will run.

Over-the-shoulder view of a person's hands tightening a fitting under a kitchen sink with a wrench, in soft overcast light

Step 4: Reconnect the supply line and test

Connect the fixture's supply line to the new valve outlet — hand-tight plus a quarter turn. Turn the main water back on slowly and immediately check the new valve joint and the supply connection for leaks. Open and close the new quarter-turn valve to confirm it seats fully. A compression joint that weeps needs a small additional nudge, not a hard crank.

Common mistakes

Not shutting the main and getting full house pressure when the valve comes off.
Overtightening a compression nut, deforming the ferring and causing a leak.
Leaving a burr on a cut pipe, which nicks a push-fit O-ring.
Trying to remove a soldered valve with hand tools — that needs a torch or a plumber.

When to call a plumber

Call a plumber if the existing valve is soldered to the copper (open-flame work in a cabinet is a fire risk and a skill), if the supply pipe is old galvanized steel that may crumble or shear when you work it, or if there is no working main shut-off to isolate the line. Replacing a section of galvanized pipe or the main stop is licensed work in many jurisdictions and can require a permit. A simple compression or push-fit swap on copper or PEX does not.

Related: how to replace a toilet supply line, how to replace a kitchen faucet, and how to thaw frozen pipes — knowing your shut-offs matters most in a freeze.

How to Replace a Water Shut-Off Valve