Quick Answer:
If water continues to flow from the tub spout after you divert to the shower, the diverter mechanism is the likely cause. First confirm the spout is a true diverter spout, then run the shower and check whether the flow at the spout drops when you divert; if it does not, the diverter isn’t engaging and the spout or its seals usually need cleaning or replacement.
Why This Happens
Most of the time the problem is a failed or blocked diverter inside the spout. Diverter designs vary: some are built into the spout itself (a pull-up or push-button on the spout), while others are part of the valve body. A worn rubber seat, corroded parts, or mineral debris can prevent the diverter from sealing, letting water continue down the spout even while the shower is on.
If you see both outlets running at once, check related problems like **Water runs from tub and shower together** for other causes. If the leak appears only when you operate the spout control, see **Leak only when diverter pulled** for more specific checks.
Step-by-Step What to Do
1. Confirm the spout type
- Look at the spout: a true diverter spout has a visible pull-up rod, push button, or built-in diverter mechanism. Some spouts are simple outlets with no diverter; those systems divert at the valve instead.
- If you’re unsure whether the diverter is in the spout or valve, stop and consider calling a plumber rather than guessing.
2. Run the shower and observe the spout
- Turn the shower on and operate the diverter as you normally would.
- Check if the flow at the spout reduces when diverted — Check if water flow reduces at the spout when diverted; if not, the diverter isn’t engaging.
- If the spout flow drops substantially, the diverter is at least partially working; if flow remains steady, it’s likely failing to seal.
3. Try cycling the diverter
- Move the diverter several times (pull/push or press) while running the shower to try to clear mineral debris.
- Sometimes repeated operation plus a short burst of higher water pressure will dislodge grit and restore sealing.
4. Inspect or remove the spout (only if comfortable)
- Identify attachment type: slip-on spouts usually have a small set screw beneath; threaded spouts unscrew. Turn off the water supply if you plan to remove it.
- Remove the spout gently and inspect the diverter, seat, and O-rings for wear, cracking, or mineral buildup. Clean or replace damaged parts.
- If you find heavy corrosion or the diverter is inside the valve body, stop and call a professional.
5. Replace the spout or diverter parts
- If cleaning doesn’t help, replacing the spout (or diverter cartridge if the diverter is in the valve) is often the next step.
- Make sure any replacement is the correct type for your system: a true diverter spout for spout-diverter systems, or the correct cartridge for valve-diverter systems.
What Not to Do
- Don’t assume some spout flow during shower is normal—steady flow usually means diverter failure.
- Don’t force, hammer, or over-tighten fittings to try to stop the leak; that can break the spout or valve and make repairs more expensive.
- Don’t use heavy adhesives or permanent sealants to block the spout; they can damage parts and make future repairs harder.
- If you can’t identify the spout type, a plumber is appropriate—don’t keep guessing.
When to Call a Professional
- If you can’t identify whether the diverter is in the spout or valve.
- If removal reveals corroded plumbing, stripped threads, or a valve that won’t shut off.
- If you’re uncomfortable removing the spout, turning off water, or working with the valve cartridge.
- If the leak has caused visible water damage or continues despite spout replacement.
Safety Notes
- Turn off the water supply before removing the spout or working on internal parts. If you must work with hot water on, be cautious of scald risk.
- Use proper tools and eye protection when removing metal parts; mineral deposits can be sharp.
- If you don’t have the correct replacement parts or the job requires valve work, stop and call a licensed plumber to avoid causing more damage.
Common Homeowner Questions
- Why is there still water coming from the spout? The diverter is not sealing due to wear, debris, or a damaged seat.
- Can I fix it myself? You can often clean or replace a spout diverter yourself if you’re comfortable removing the spout and have basic tools.
- How urgent is this repair? It’s worth fixing promptly to avoid wasted water and possible damage, but it’s not usually an immediate emergency unless there’s active flooding.
For more related articles, see the Tub Spout Leaks When Shower Is On hub.