Quick Answer:
If the rest of the house has water but the bathtub won’t fill, start with simple checks at the tub: make sure the handle is in the correct position, test hot and cold separately, and look for a nearby shutoff valve that may still be closed. If nothing obvious shows, remove the tub spout and check the cartridge or valve body for debris. If you recently shut water off and reopened it, open the supply slowly — see turn the water back on safely for general guidance — and check the **main water shutoff valve location** if multiple fixtures are dead.
Why This Happens
- Single-fixture shutoff valves (behind the tub or under an access panel) were left closed after work or a shutoff and block supply to the tub only.
- Debris or mineral build-up from pipes got trapped in the tub valve or cartridge when water was turned back on, blocking flow to the spout.
- The handle or trim isn’t aligned with the valve position, so the valve isn’t opening fully even though the water is on.
- The tub spout itself (slip-on or screw-on) can hide blockages or diverter problems that stop flow to the tub.
- In rare cases a damaged cartridge or internal valve part fails to open or has broken pieces inside.
Step-by-Step What to Do
1. Check tub handle position
- Look at the handle: is it turned to the full on position or sitting between on and off? Some single-handle valves need a clear full-turn to direct water to the spout.
- If the handle feels stuck, stop and refer to the “What Not to Do” section below before trying to force it.
2. Test hot vs cold
- Turn only the hot side, then only the cold side. If one side works and the other doesn’t, the issue is likely inside the valve or a blocked supply line to that side.
- If both sides are dead while other fixtures work, the problem is likely the tub valve or a nearby shutoff.
3. Inspect nearby shutoff valves
- Look for an access panel on the tub surround or a small shutoff ball/angle valve under an access plate. These valves can be left closed after repairs or winterizing.
- If you can’t find a local valve and multiple fixtures are out, you may need to check your home’s main shutoff — review the **main water shutoff valve location** if unsure where yours is.
4. Remove and clean the tub spout
- Many tub spouts are slip-on (push on with a set screw) or screw-on. Inspect the base for a set screw (usually under the spout) and remove it gently, or unscrew the spout if it turns.
- Once off, check for mineral deposits, tape, or debris inside the spout and the pipe nipple. Clean with a rag and vinegar if needed, then refit and test.
- If the spout contains a diverter, verify the diverter moves freely and doesn’t block flow to the tub.
5. Check cartridge for debris
- Turn off water to the tub (local shutoff or main) and relieve pressure by opening another faucet. Remove the handle and trim to expose the cartridge or valve stem.
- Inspect for visible debris, mineral build-up, or broken pieces. Flush the valve body gently, and if possible remove the cartridge and rinse it. Reassemble and test.
- If the cartridge looks damaged or you’re unsure how to remove it, stop and consider calling a professional; cartridges must be handled carefully to avoid leaks or further damage.
What Not to Do
- Do not force the handle — forcing can break internal parts and make the repair more expensive.
- Do not overtighten trim screws when you reassemble the faucet; that can crack the trim or distort the valve alignment.
- Do not keep running water if you see leaking behind the wall — shut the water off immediately and call for help.
When to Call a Professional
- Water continues to leak behind the wall or into ceilings/floors after you shut the water off.
- You remove the cartridge and see damage, broken pieces, or corrosion you can’t safely clean or replace.
- The local shutoff is missing and multiple fixtures are dead, indicating a larger supply or valve problem.
- You’re not comfortable removing trim, spouts, or cartridges — a plumber can do this without causing more damage.
Safety Notes
- Always turn off water to the fixture before removing cartridges or spouts. If uncertain, shut off the home’s main water supply first.
- Relieve pressure by opening a lower faucet before disassembly to avoid spray from pipes.
- Wear gloves and eye protection when cleaning mineral deposits or flushing debris from valve bodies.
- If you see active leaks inside walls, stop work immediately and shut off water — continued running can cause structural damage and mold.
Common Homeowner Questions
- Why do only some fixtures work after I turned the water back on? Often a local shutoff for that fixture was left closed or debris settled into that branch when water was shut off.
- Can I clean a cartridge myself? Yes for light mineral build-up — turn off water, remove cartridge per manufacturer instructions, rinse and reassemble. Replace it if damaged.
- How long can I wait to call a plumber? Call right away if you find leaks, broken parts, or if you’re unsure how to reassemble the valve; small delays can lead to bigger damage.