Leaking Valve Stem
Updated February 20, 2026
Water dripping from around the valve handle or packing nut -- packing failure, not a pipe leak. Fix is usually tightening the nut or replacing the packing, often with the water still on.
Overview
Every shutoff valve, hose bib, and gate valve has packing that seals the stem where it passes through the body. Packing nut compresses it. Over time, the material dries out and loses its seal. Water drips from around the handle -- sometimes only when turning, sometimes continuously. One of the simplest plumbing repairs. Quarter turn on the packing nut fixes most. If not, replace the packing material -- 15 minutes, under $5. Address it promptly because water running down a valve stem damages walls, floors, and cabinets.
Symptoms
- Dripping from around the handle or from the packing nut -- steady or only when the valve is turned
- Water stains, mineral deposits, or green corrosion on the valve body below the nut -- leak has been going for a while
- Only leaks when operated, stops when stationary -- stem movement breaks the marginal seal
- Leaks continuously whether the handle is being turned or not -- packing has fully deteriorated
- Water dripping down the pipe below the valve, looks like a pipe leak -- but the source is the packing nut above, water running down the body
- Hose bib leaking behind the handle when turned on -- outdoor valves fail faster from temperature extremes
Common Causes
- Dried-out packing -- graphite string, rubber, or Teflon around the stem hardens and loses flexibility over years. Cannot conform to the stem surface anymore. Most common cause, normal wear item.
- Loosened packing nut -- vibration from water flow, water hammer, or nearby appliances gradually loosens the nut. Less compression on the packing, water gets past. Common near washing machines and dishwashers.
- Corroded or scored stem -- pitting, corrosion, or scratches on the stem surface prevent even new packing from sealing. Common on older brass valves or valves that were forced when stuck.
- Previously overtightened -- someone cranked the nut to stop a drip, crushed the packing permanently. Crushed packing cannot spring back or seal. Can extrude past the nut, creating gaps.
- Temperature cycling on hose bibs -- outdoor faucets go through extreme swings. Packing expands and contracts, freeze-thaw cycles crack it faster than indoor valves.
What You'll Need
How to Fix It
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Tighten the Packing Nut
First thing to try. Adjustable wrench, packing nut (hex nut behind the handle) clockwise a quarter turn. Do not overtighten -- small additional compression often restores the seal. Operate the valve, check for dripping. Stopped? Done. Reduced but not stopped? Another eighth to quarter turn. Nut already very tight and handle hard to turn? Packing needs replacing, not more tightening.
Tip: You can do this with the water on. No need to shut off upstream. Towel ready in case the drip increases briefly while working. -
Replace the Packing Material
Tightening did not work? Replace the packing. Water can stay on if the valve is fully open or fully closed (pressure holds the stem). Remove the packing nut counterclockwise, slide up the stem. Dig out old packing with a pick, small screwdriver, or needle-nose pliers. Clean the stem and inside the nut. Wrap new graphite packing string around the stem -- 3-4 wraps clockwise so tightening compresses them, not unwinds. Nut back down, snug. Operate and check.
Tip: Graphite packing string ($3-5, any hardware store) works on virtually all valve types. Clockwise wraps (looking from the handle end) so the nut compresses them tighter. -
Alternative: Use a Packing Washer or O-Ring
Some valves use a flat packing washer or O-ring instead of string. Find a ring or disc inside the nut? Replace with a matching one. Bring the old part to the store. Plumber's grease on the new washer before installing. Valves that had string packing can often be upgraded to a Teflon packing washer for longer life.
Tip: Not sure which type? Remove the nut and look. String packing: fibrous material wrapped around the stem. Washer: distinct rubber or Teflon ring sitting inside the nut. -
Inspect the Valve Stem for Damage
Packing nut off? Inspect the stem. Should be smooth, no pits, scratches, or corrosion. Run your fingernail along it -- grooves or rough spots mean the surface is compromised and may not seal even with new packing. Light corrosion: polish gently with 400-grit emery cloth. Severely pitted or scored? Replace the valve.
Warning: No coarse sandpaper or files on the stem. Removing material changes the diameter and makes packing worse. Fine emery cloth only (400+), light pressure. -
Replace the Valve (If Stem Is Damaged)
Stem too far gone or valve body cracked? Full replacement. Water off upstream. Two wrenches (one holds the pipe, one turns the valve) to avoid torquing the pipe. New valve -- upgrade gate valve to quarter-turn ball valve. Less prone to packing leaks and corrosion. Teflon tape on threaded connections, or push-fit if the pipe was cut.
Tip: Ball valve with O-ring bonnet design instead of traditional packing. Virtually maintenance-free, rarely develops stem leaks. -
Address Hose Bib Packing (Outdoor Faucets)
Hose bibs are the most common location because of temperature exposure. Same process: tighten the packing nut, then replace packing if needed. Frost-free bibs: packing nut behind the handle, same location. Old bib with corroded packing nut that will not come off without damage? Replace the entire bib.
Tip: Check the vacuum breaker (small cap on top) too. A leaking vacuum breaker drips down the body and looks exactly like a packing leak.
When to Call a Pro
Call a plumber if the valve needs full replacement and is in a hard-to-reach spot (wall, crawl space), if it is soldered into copper and you are not comfortable resoldering, if repacking has not stopped it and you cannot figure out why, or if multiple valves are leaking at once (may indicate high water pressure accelerating wear system-wide).
Prevention Tips
- Exercise all shutoff valves once or twice a year. Full off, full on. Keeps the stem and packing from drying out and seizing.
- Do not overtighten packing nuts. Snug is sufficient. Overtightening crushes packing and makes the valve harder to turn, accelerating wear.
- Fix packing drips promptly. Small drip left alone causes significant damage over time, and the leak only gets worse.
- Graphite-impregnated string for replacements. Works on all valve types, resists heat, chemicals, and compression set.
- Hose bibs: plumber's grease on the stem and packing area at the start of each season. Lubricates and maintains the seal despite temperature cycling.
- Multiple valves leaking at once? Test your water pressure. Above 80 PSI accelerates packing wear system-wide.