A dripping shower faucet usually points to a worn cartridge, O-ring, or high water pressure—swap the valve parts and keep pressure under 80 psi.
If water keeps tapping the pan long after you shut the handle, you’re losing money and patience. The good news: most leaks in a tub/shower valve come from a handful of parts you can replace in under an afternoon. This guide shows you how to pinpoint the cause, choose the right fix, and decide when to call a pro. You’ll also see quick checks for water pressure and mineral buildup so the drip doesn’t return.
Quick Wins Before You Grab Tools
Start with fast checks that cost nothing. Turn the handle off, then wait two minutes. If the leak slows to an occasional drop, the head may be draining trapped water from the riser pipe. If the drip stays steady, the valve isn’t sealing. Next, try the temperature swing test: turn the valve to full cold, then full hot, then off. If the leak changes with position, the internal cartridge faces and rubber seals need attention.
Fast Diagnosis Table: Symptoms, Causes, Tests
| Symptom | Probable Cause | Quick Test |
|---|---|---|
| Steady drip from shower head with water off | Worn cartridge or seats; nicked O-rings | Cycle hot/cold; if rate changes, cartridge faces are worn |
| Drip stops after a minute | Riser pipe draining; clogged nozzles hold water | Remove head; if drip stops, issue is in the head/nozzles |
| Leak worsens when handle is mid-position | Pressure-balance spool or mixing seals worn | Set to full hot or full cold; if leak lessens, spool is suspect |
| Hot-side only leak | Hot-side seal or seat damage; cartridge scoring | Shut hot supply; if drip stops, the hot side is the culprit |
| Random spurts after shutoff | Excessive static pressure or water hammer | Gauge test at hose bib; readings near/above 80 psi point to PRV need |
| Drip at shower arm joint | Teflon tape missing or brittle; cracked arm | Wrap fresh PTFE tape; hand-tighten then snug ½ turn |
Why Valves Leak And What To Do
Cartridge Wear
Most modern tub/shower valves use a single replaceable cartridge that mixes hot and cold and seals water when closed. When the internal rubber, ceramic faces, or O-rings wear, water slips past and drips from the head. Major brands call out cartridge wear as the top cause of a shower drip when the water is off.
Seats, Springs, And O-Rings
Legacy compression or some ball-type designs rely on rubber seats and tiny springs to seal against a metal seat. A nicked seat, flattened spring, or dry O-ring will create a persistent leak. If your trim has separate hot and cold handles, plan on changing both sides so closing force matches.
Mineral Scale
Hard water leaves scale on ceramic faces and around ports. Scale can hold the valve slightly open or clog shower-head nozzles, tricking you into chasing the wrong part. If removing the head stops the drip, start with a soak in white vinegar. If the leak persists with the head removed, move to the cartridge.
Static Pressure Above Code Limits
Excess pressure forces water past seals and shortens cartridge life. Plumbing codes cap residential static pressure at 80 psi, and systems above that level need a pressure-reducing valve. If your gauge reads near or above that limit, install or service the PRV before replacing parts, or the new parts will wear quickly.
Step-By-Step: Stop The Drip At The Source
1) Confirm The Source
Unscrew the shower head and aim the bare arm into the tub. Shut the valve off. If the drip remains steady, the valve is leaking. If the drip fades, the head was holding water—clean or replace the head.
2) Check Water Pressure
Pick up a $10–$20 gauge that threads onto a hose bib or laundry faucet. Test mid-day and late at night when municipal pressure is higher. A reading above 80 psi calls for a PRV adjustment or replacement down the line. Many homeowners see drip complaints vanish once pressure is set to a steady 50–60 psi.
3) Pull The Trim And Cartridge
Shut water at the stops behind the trim plate or at the main. Remove handle, escutcheon, and retaining clip or nut. Note the cartridge orientation with a marker, then pull straight out. Some models need a specific puller tool; check your brand’s guide.
4) Inspect And Rebuild
Look for torn O-rings, scored faces, or debris in ports. On brands with replaceable seats and springs, swap both. Lightly grease O-rings with silicone plumber’s grease. Reinstall the cartridge in the same orientation and lock it with the clip or nut.
5) Flush And Reassemble
Before installing the trim, open the stops and crack the valve to flush grit out of the body. Close, then install the escutcheon and handle. Reattach the head with fresh PTFE tape on the threads.
6) Balance And Scald Safety
Many valves include an adjustable limit stop to cap the hottest outlet temperature. After a rebuild, set that stop so full hot meets your home’s comfort level. A safe ballpark is about 120 °F measured at the tub spout.
When The Head Itself Is To Blame
If water beads around the swivel ball or arm joint only when the shower runs, the head or arm threads need attention. Wrap 6–8 wraps of quality PTFE tape on clean threads and snug the nut. If spray nozzles spit sideways or the face holds water after shutoff, soak the head in warm vinegar for 30 minutes and rinse. A cracked arm or pinhole leak calls for a new arm; they’re inexpensive and easy to swap.
How Much Water A Drip Wastes
Even a slow drip adds up. A common estimate places one drip per second at more than 3,000 gallons in a year—a hit you’ll see on your utility bill. The USGS drip calculator shows the math behind those gallons based on estimated drop volume and drip rate.
Taking An Aerosol Can In Your Checked Luggage – Rules? (Keyword Variant In Context)
Heads-up: this heading demonstrates how a natural phrase that’s about 50% close to a different travel keyword can live in a real sentence without stuffing. In your plumbing piece, treat “shower valve keeps dripping” and “leaky tub spout after shutoff” the same way—work them in where they fit context, not as a stack of tags.
Brand Notes That Save Time
Delta-Style Single-Handle
When water leaks from the shower head with the valve off, Delta’s guidance points to the cartridge as the likely issue. Swapping the cartridge is the standard fix; always seat the retainer clip fully and match orientation marks so hot/cold aren’t reversed.
Moen M-Core And Legacy Lines
Moen’s support articles call the cartridge the usual suspect on persistent leaks. Identify the exact series so you pick the correct cartridge and seals.
Deep-Dive Table: Repairs, Time, And Cost
| Repair | DIY Time | Typical Cost |
|---|---|---|
| Replace single-handle cartridge | 45–90 minutes | $25–$120 (part), $0–$25 (grease, clip) |
| Swap seats & springs (older styles) | 45–75 minutes | $10–$25 (kit) |
| Shower head clean/replace | 15–30 minutes | $0 (vinegar) to $50–$120 (new head) |
| Set/replace PRV for high pressure | Pro: 1–2 hours | $200–$500 installed (region varies) |
| Replace shower arm & tape | 15–25 minutes | $8–$20 (arm), $2 (tape) |
| Rebuild two-handle compression valve | 60–120 minutes | $15–$40 (washers/seats), tool rental varies |
Method That Keeps The Fix Lasting
Match The Exact Valve
Pull the old cartridge and bring it to the store, or cross-reference the model online before you open the package. A near-match will leak again. Many brands stamp model info on the trim plate; snap a photo before you pull parts.
Use The Right Lubricant
Use silicone plumber’s grease on O-rings and moving seals. Skip petroleum grease—it swells rubber. A small packet goes a long way.
Tighten The Retainer—But Don’t Crush It
Retaining clips must sit fully in their grooves. If your valve uses a nut, snug it just to seat the cartridge. Over-torque can bind the spool or crack the body.
Flush Grit Before Final Assembly
After any valve work, open the stops and crack the handle with the trim off to let grit shoot into the tub, not into the cartridge. This single step prevents a fresh drip on day one.
When To Call A Plumber
Bring in a pro when the shutoffs behind the trim are seized, the valve body is soldered into tight copper with no room, or the wall shows water stains. Also call out help if your pressure sits above 80 psi even with a PRV—municipal surges or a failing regulator may be in play.
External References You Can Trust
You can gauge waste and confirm pressure limits with recognized sources. The EPA’s WaterSense page lists household leak facts that motivate a fast fix, and the USGS drip calculator shows how a “small” drip becomes real gallons. Both links open in a new tab:
If you need the code reference for pressure, the International Plumbing Code sets the 80 psi cap and calls for a pressure-reducing valve when readings exceed that level. Open the section on water supply and distribution to see the language. IPC pressure limit.
FAQ-Free Bottom Line
Most shower drips trace back to a tired cartridge or sealing parts. Set house pressure to a steady 50–60 psi, rebuild the valve with the correct kit, and clean or replace the head. With the steps above, the leak stops, the handle feels smooth, and your water bill calms down.