When a shower keeps running, a stuck valve or worn cartridge is the usual cause—shut off water, check the handle, then service or replace the cartridge.
Your shower handle spins, but water still pours. The noise grows, the bill climbs, and every minute raises the risk of damage. Here’s a clean, no-nonsense guide to stop the flow fast, figure out why it’s happening, and make a lasting fix—whether you’re handy or calling in a pro.
Shower Keeps Running: Causes And Fast Fixes
Most cases track back to one of three parts inside the mixing valve: the cartridge (or stems on older valves), the handle hardware, or the tiny shutoff “stops” built into some valves. Minerals and wear make parts stick. Plastic seals harden. Screws loosen. Good news: the repair path is straightforward once you identify which part is to blame.
First Response: Stop The Flow Safely
Before you pull trim or buy parts, shut off water. Some valves include small screwdriver stops on the body behind the trim plate. If you see them, turn both hot and cold to the off position to isolate the shower. Many Delta and Moen valves use this style; brand support pages show where these stops sit and how to turn them. If your trim hides no stops, close the home’s main shutoff, then open a nearby sink to drain pressure.
| Symptom | Likely Cause | Immediate Action |
|---|---|---|
| Handle turns but water won’t stop | Worn or jammed cartridge / stem | Shut water; remove handle & pull cartridge for inspection |
| Handle is stiff or grinds | Mineral buildup on cartridge seal surfaces | Shut water; pull cartridge; clean or replace |
| Handle spins loose with little control | Loose handle screw or stripped adapter | Tighten screw; replace adapter or handle kit if worn |
| Hot won’t shut off; cold does | Failed hot-side seal or pressure-balance hang-up | Shut water; service cartridge/pressure balancer |
| No trim stop screws visible | Valve without integral stops | Use main shutoff; plan a cartridge puller if stuck |
Turn Off Water: Two Paths That Work
Method A: Close The Valve’s Built-In Stops
Remove the handle and escutcheon to expose the valve body. Look for a pair of small, slotted screws—one on each inlet. Turn both to the closed position. Some models show a slot orientation that indicates open or closed. Many manufacturer pages show the slot position and the safe way to drain residual water before service; these visuals help you match what you see in the wall.
Helpful reference: see a manufacturer guide on operating stop check valves for a popular pressure-balance body (open/closed slot positions and drain step). Stop check valve instructions.
Method B: Use The Home’s Main Shutoff
If there are no stops—or they’re frozen—close the main. In cool climates the main often sits in a basement or utility space; in warm zones, it may sit on an exterior wall or inside a yard box. Ball valves turn a lever a quarter turn; gate valves turn a round wheel clockwise. After closing, open a sink to bleed pressure before you open the shower valve.
For a quick locator guide with photos of common main-valve styles and spots, see this clear walk-through: main water shutoff basics.
Find Your Valve Type: Single-Handle Or Separate Stems
Single-handle showers combine hot and cold inside a cartridge. Two- or three-handle sets use individual stems and seats. The repair is similar in spirit: isolate water, remove trim, pull the moving part, refresh seals, reassemble, and test. The right parts and tools make the difference between a one-hour fix and a weekend headache.
Tools That Save Time
- Allen key or Phillips driver for the handle screw
- Flat screwdriver for trim and stop screws
- Slip-joint pliers and an adjustable wrench
- Cartridge puller sized for your brand (huge help with stuck parts)
- Plumber’s grease, replacement O-rings, seats/springs (brand-specific)
- White vinegar or a descaler for mineral buildup
- Towel and bucket to catch residual water
Step-By-Step: Restore Control On A Single-Handle Mix Valve
1) Remove Handle And Trim
Pop the index cap, remove the screw, and pull the handle straight off. Back out the escutcheon screws and slide the plate forward. Place a towel in the tub to protect the surface and catch small parts.
2) Close Stops Or Main, Then Relieve Pressure
Close the two trim stops if present. No stops? Close the main and open a sink nearby. Dribble from the shower is normal as the valve drains down.
3) Pull The Cartridge
Most cartridges lock in with a clip or a retaining nut. Remove the clip, then use straight pull force on the cartridge—not prying on the brass body. For popular pressure-balance designs, manufacturer instructions warn against prying; instead, place the handle on the stem and rotate a fraction to break the seal, then pull. A puller tool beats pliers when minerals lock things in place.
Good visual explainer with safe removal tips from a trusted brand: cartridge handling notes.
4) Inspect, Clean, Or Replace
Look for torn O-rings, grooved plastic, or crusty buildup. If the body looks sound and the cartridge is only scaled, soak it in warm vinegar, rinse, grease the O-rings, and reinstall. If seals look chewed or the stem wobbles, swap in a new cartridge matched to your valve series.
5) Reassemble And Test
Push in the cartridge in the same orientation it came out—hot and cold must land on the correct sides. Reinstall the clip or nut. Open the stops or main slowly. Check for drips at the body, then run the shower. Verify smooth rotation and firm shutoff. If your model has a temperature limit stop under the cap, set a safe max as the brand shows.
Two- Or Three-Handle Sets: Seats And Stems
Older valves use individual stems and a seat inside the body. Drips or run-on often trace to a worn seat or stem washer. With water isolated, remove each handle and trim, unthread the stem with a socket, and replace the washer and seat. Use a seat wrench for the inset part. Grease new washers lightly before reinstalling. After assembly, open water slowly and test each handle for crisp shutoff.
When The Handle Moves But Flow Won’t Stop
This pattern screams “pressure-balance hung” or “seal failure.” The internal piston can stick after years of mineral exposure. A fresh cartridge resets the mechanism. If temperature swings were common before the failure, plan to replace—not just clean—the moving parts inside.
Brand Clues, Parts, And Fit
Trim shape, screw pattern, and the old cartridge’s silhouette can reveal brand and series. A photo at the store counter or on a brand help page can confirm a match. Keep the old part for comparison. If you can’t match it, look behind the escutcheon for a stamped model code on the valve body.
| Brand Signs | What To Photograph | Why It Helps |
|---|---|---|
| Distinct handle hub or cap logo | Front of handle and index cap | Confirms brand for cartridge match |
| Unique clip/retainer shape | Valve front with clip in place | Narrows series within a brand |
| Body casting marks on the valve | Stamped codes on brass body | Exact series ID for parts list |
| Stop screw positions on inlets | Both inlet sides, close-up | Shows presence of integral stops |
| Trim plate hole pattern | Back of escutcheon | Ensures new trim fits your body |
Common Roadblocks And How To Beat Them
Stuck Cartridge
Heat, minerals, and time glue O-rings to the valve. A dedicated puller applies straight force and keeps the cartridge square. Gentle rotation with the handle on the stem can break adhesion before you pull. Avoid prying against the valve body to prevent damage to the brass.
Frozen Trim Stops
If the small stop screws won’t budge, don’t strip them. Close the main instead, then plan to free or replace the stop assemblies later. A tiny dab of penetrating oil on the screw head can help next time after the system is depressurized.
Leaky After Reassembly
Drips at the body usually mean an O-ring rolled or the clip isn’t fully seated. Pull and reseat. If the handle won’t point level, the cartridge may be 180° off; flip it.
Temperature Too Hot After Repair
Many single-handle valves include a limit stop under the cap. Set a safe max by rotating the stop per the brand’s diagram. This prevents scald risk after service. A brand support page shows step-by-step adjustments with photos and video. See this reference for a typical dual-function trim: rotational limit stop setup.
Maintenance That Prevents A Repeat
- Flip those trim stops once or twice a year to keep them free.
- Clean the inlet screens or replace seats and springs during any cartridge swap.
- Grease O-rings during service so they don’t stick to the body.
- Check handle screws each season so the hub doesn’t strip.
- Keep a photo log of the valve body and parts for easy match later.
When To Call A Plumber
If the valve body leaks from a crack, if the cartridge breaks off inside the bore, or if corrosion has thinned the supply lines, step back. A pro can extract stuck parts cleanly and pressure-test the work. If tile must be opened wider than the trim plate covers, a service panel or remodel plate can save the wall.
Reference Walk-Throughs For Deeper Work
If you want a complete visual guide to pulling and replacing a mixing cartridge, this step-driven tutorial is a solid blueprint from a widely trusted home-repair brand: cartridge replacement guide. For older multi-handle sets, a separate stem-and-seat guide from the same source shows the flow from teardown to reassembly, including seat tools and washer swaps.
Fast Checklist: From Panic To Quiet
- Kill the water: trim stops on the valve, or the home’s main.
- Open a nearby sink to release pressure.
- Pull the handle and escutcheon; stage a towel and bucket.
- Remove clip or nut; extract the cartridge with straight pull.
- Clean light scale or install a new, matched cartridge.
- Grease O-rings; reinsert in the correct orientation.
- Open water slowly; check for leaks; set the temperature limit stop.
Peace Of Mind Going Forward
A steady shutoff and smooth handle feel come from fresh seals and clean movement. Once you know where your main lives and how your valve is built, the next hiccup won’t rattle you. Keep a spare cartridge on the shelf if your area has hard water and your valve model is common. That little box can turn a late-night scramble into a ten-minute tune-up.