Symptoms
- No leak when the valve is left alone, but drips when turned
- Water seeping from around the valve handle or stem
- Valve feels stiff or gritty to operate
- Valve hasn't been used in a long time before this occurred
Likely causes
- CommonWorn packing material around the valve stemThis soft packing seals the stem where it passes through the valve body, and it dries out or wears with age and infrequent use.
- CommonLoose packing nutThe nut that compresses the packing material can loosen over time, reducing the seal's effectiveness.
- PossibleCorroded or worn valve stemA pitted or corroded stem surface won't seal well against packing even if the packing itself is fine.
- Less commonOld valve simply failing internallyOlder valves, especially compression or gate types, can fail in ways beyond just the packing seal.
What to do
- Try tightening the packing nut (located just behind the handle) slightly with a wrench while the valve is in the position causing the leak.
- Turn it in small increments and test, since overtightening can make the valve too stiff to operate.
- If tightening doesn't stop the leak, shut off water further upstream (like the main) and disassemble the packing nut fully.
- Remove the old packing material and wrap new packing string or install a packing washer rated for potable water use.
- Reassemble, tightening the packing nut snugly but not excessively.
- Turn the main water back on and test the valve at different positions to confirm the leak is resolved.
- If the valve continues leaking after repacking, it's often more cost-effective to replace the whole valve rather than keep repairing it.
Tools and parts
- Adjustable wrench
- Packing material
Valve packing kitSearch: “valve stem packing kit”
When to call a pro
Call a plumber if repacking doesn't resolve the leak, since full valve replacement may be the more practical fix.
Safety
Generally low risk
Generally low risk for a careful person. Stop if anything looks different from what this guide describes.