Quick answer
A shut-off valve (angle stop) that leaks usually leaks from the stem when it is turned, which a small snug of the packing nut behind the handle often stops, or from the compression nut where it meets the pipe, or from the supply line connection. An old multi-turn valve that leaks or will not close fully is usually replaced with a quarter-turn valve. Put a bowl under it, close the main if it drips steadily, and do not force a corroded handle. HomeAdvisor puts a kitchen faucet replacement at $162–$364 installed, a job that usually includes new valves. Call (888) 217-6781 to reach a plumbing company taking calls in your ZIP.
Follow the short menu, then your 5-digit ZIP. The line goes quiet for a few seconds while it connects; stay on. If it does not connect, call once more: companies taking calls change minute to minute.
Written & reviewed by Marcus ReedIICRC WRT
Reviewed November 4, 2026· Next review May 2027
The small valves under sinks and behind toilets, called angle stops, often sit untouched for years. The day you turn one, it starts dripping. That is usually the stem packing, and it is often a small fix. A valve that leaks on its own, or will not close, needs replacing.
Find Where It Leaks
Dry the valve and the pipes with a towel, put a dry paper towel under it, and watch.
| Where the drip forms | Likely cause | First step |
|---|---|---|
| Around the handle stem | Worn packing | Snug the packing nut behind the handle a quarter turn |
| Where the valve meets the wall pipe | Compression nut or ferrule | Snug a quarter turn, holding the valve body steady |
| Where the supply line connects | Supply line nut or a worn line | Tighten, or replace the supply line |
| From the valve body | Corroded or cracked valve | Replace the valve |
| Valve will not close fully | Worn washer inside | Replace the valve |
Do This Now
- Put a bowl or towel under it.
- If it drips steadily, close the main water valve until it is fixed. See emergency water shut-off.
- Do not force a corroded handle. It can snap the stem off, and then the valve cannot be closed at all.
Talk to a plumber about this
One call reaches a plumbing company taking calls in your ZIP.
Replacing the Valve
With the main closed, the old valve comes off the pipe and a new one goes on, often a quarter-turn ball valve that is easier to close in an emergency. Compression valves fit copper; push-fit valves fit several pipe types. It is a common short job, and many plumbers replace these valves whenever they install a faucet or toilet. HomeAdvisor puts a kitchen faucet replacement at $162–$364 installed.
Water Under the Sink
A slow drip that has been going a while soaks the cabinet floor. If the base is soft or musty, see water damage under the kitchen sink and leak under the bathroom sink.
The Call
Call when the valve leaks from the body, will not close, or the handle is seized. (888) 217-6781 connects you to a plumbing company taking calls in your ZIP. Follow the short menu, enter your 5-digit ZIP and stay on while it connects; if it does not connect, call once more, because the companies taking calls change minute to minute.
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Frequently Asked Questions
Why is my shut-off valve leaking?
The packing around the stem has worn, the compression nut at the pipe is loose, the supply line connection has failed, or the valve itself has corroded.
Can I just tighten a leaking shut-off valve?
A quarter turn on the packing nut or compression nut often stops a small leak. Overtightening a compression nut can crush the ferrule and make it worse.
Should I replace old shut-off valves?
Old multi-turn valves seize and leak when finally turned. Many plumbers replace them with quarter-turn valves during any faucet or toilet job.
Sources
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Disclaimer: HearthDry is an independent educational resource. This article is for informational purposes only and does not constitute professional, legal, or insurance advice. Consult licensed professionals before making decisions about your property or insurance claims.
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