Most Likely Causes (Ranked)
Inside the shower head where it threads onto the shower arm, there's a small rubber washer. This washer compresses between the shower head and the arm to create a seal. Over 3-10 years, it hardens, flattens, or cracks. The result is a slow drip from the connection point (where the head meets the arm), not from the spray nozzles. Hot water accelerates washer deterioration.
When you turn off the shower, the diverter valve (or the mixing valve cartridge inside the wall) should seal completely. Mineral deposits from hard water accumulate on the valve seat, preventing a complete seal. Water weeps past the deposit and drips from the shower head at 1-10 drips per minute. This is why shower head drips are more common in hard water areas.
Plastic shower heads develop hairline cracks from drops, overtightening, or age. Metal heads can crack at threaded connections if cross-threaded during installation. A crack in the head body sprays water sideways or drips from an unexpected location.
The shower head simply isn't tight enough on the shower arm, or the Teflon tape on the threads has deteriorated. This is the simplest cause and the first thing to check. Over time, thermal expansion and contraction during hot showers gradually loosens the connection.
The mixing valve cartridge inside the wall (Moen 1222, Delta RP46074, etc.) has internal seals that wear. When they fail, water passes through even when the handle is in the off position. This causes the shower head to drip continuously. If both hot and cold water pass through, the drip may be warm.
How to Fix It
Replace the Washer or Tighten the Connection
Free-$1- 1Unscrew the shower head by hand (turn counterclockwise). If stuck, wrap a cloth around it and use pliers.
- 2Inspect the rubber washer inside the head's threaded connection. If it's flat, hard, or cracked, replace it. Universal shower head washers are $1 for a 10-pack.
- 3Clean old Teflon tape from the shower arm threads. Apply 5-6 clockwise wraps of new Teflon tape.
- 4Screw the head back on hand-tight, then a quarter turn with cloth-covered pliers. Don't overtighten.
- 5Run the shower and check the connection for drips.
Clean or Replace the Valve Cartridge
$15-40 DIY / $150-300 Pro- 1Turn off water to the shower (either dedicated valve or main shutoff).
- 2Remove the handle (usually a set screw under a decorative cap), then the trim plate/escutcheon.
- 3Pull or unscrew the cartridge. Note the brand — Moen, Delta, Kohler each have specific cartridge types.
- 4Soak in white vinegar overnight to dissolve mineral deposits, or install a new cartridge.
- 5Reassemble, turn on water, and test in both hot and cold positions.
Replace the Shower Head
$15-80- 1Simply unscrew the old head, clean the arm threads, apply Teflon tape, and install the new head.
- 2This is the right fix if the head body is cracked or if clogged nozzles resist cleaning.
- 3A quality shower head like the Speakman S-2005-HB ($30) or Moen Magnetix ($40) will outlast a cheap replacement.
When to Call a Professional
A drip behind the escutcheon plate (the round cover on the wall) means water is entering the wall cavity — this causes hidden mold and rot.
If you see staining on the ceiling below a second-floor shower, the leak may be in the valve body, not the head.
Cross-threading the shower head can crack the shower arm inside the wall — use hand pressure only when starting the threads.
How to Prevent It
Clean the shower head monthly with vinegar to prevent mineral buildup (soak in a bag tied around the head).
Replace rubber washers every 5 years proactively.
Don't overtighten — hand-tight plus a quarter turn is sufficient.
Install a water softener if you have hard water — extends the life of all plumbing components.
Frequently Asked Questions
Water trapped in the head and arm drains by gravity for 1-2 minutes — that's normal. If it continues beyond 5 minutes or drips steadily, it's a valve or washer issue.
For the shower head washer: yes, just unscrew the head while the shower is off. For the valve cartridge: no, you must shut off the water supply.
At 10 drips per minute: about 500 gallons per year ($5-10). At a slow stream: up to 5,000 gallons/year ($50-100).
Shower head and washer replacement: DIY in 10 minutes. Valve cartridge: intermediate DIY. Only call a plumber if you can't identify the valve brand or if there's a leak inside the wall.