Does a nearby sink get hot?
If yes, the tub valve branch is the stronger lead.
Bathtub hot-water troubleshooting
Bathtub No Hot Water? Check the Valve Limit Stop
If only the bathtub has no hot water, the first suspect is the tub/shower valve: an anti-scald limit stop, stuck cartridge, or pressure-balance cartridge can block the hot side. If nearby sinks also lack hot water, start at the water heater or whole-home supply instead.
The strongest clue is a nearby sink getting hot while the tub stays cold or lukewarm.
Measure temperature first, then decide whether the problem is whole-home hot water or the bathtub valve.
Don’t start with: Do not replace a water heater or cartridge until you compare the tub with another hot fixture.
If the sink gets hot and the tub does not,check the tub valve limit stop and cartridge.
If every fixture is cold,leave the tub trim alone and diagnose the water heater branch.
Do this first
- Do not open valve trim until you know how to shut water off if a cartridge comes loose.
- Avoid scalding tests; use a thermometer and modest water flow.
- Stop if the handle, retaining clip, or cartridge is corroded or stuck.
- Do not force a handle held by a hidden set screw.
- Call a licensed plumber if the cartridge will not move, the valve body leaks, or whole-home hot water is affected.
Last reviewed: 2026-06-28
No-hot-water sorter
Is the tub only lukewarm at the hottest setting?
The anti-scald limit stop may be set too low or damaged.
Is the tub fully cold?
A stuck cartridge or blocked hot side may be involved.
Do all fixtures lack hot water?
Start at water heater or supply, not the tub valve.
Does pressure change when turning hot?
A pressure-balance cartridge can block or restrict the hot side.
How to separate tub-only no hot water
The best first check is comparison. If the sink is hot and the tub is cold, the tub valve becomes the target.
Before you buy anything
Compare the tub with a nearby sink and record the temperature clue. A limit stop, cartridge, and pressure-balance cartridge are tub-valve parts, not whole-home hot-water fixes. Match the exact diagnosis, fixture style, and model or valve family before ordering.
What is usually happening
A bathtub with no hot water is often a local valve problem, but only if other fixtures still get hot. The first homeowner check is a measured comparison: run a nearby sink hot, then test the tub at its hottest setting and note whether the tub is cold, lukewarm, or slow to warm.
- A nearby hot sink proves the water heater can deliver hot water to the bathroom.
- A low anti-scald limit stop can make the tub stay lukewarm at the hottest handle position.
- A stuck cartridge can block or restrict hot-side water.
- A whole-home no-hot symptom belongs at the water heater or supply branch.
What not to do first
The most expensive wrong move is replacing parts before comparing fixtures. Start with evidence you can see and measure.
- Do not open the tub valve before testing a nearby sink.
- Do not assume the water heater is bad when only the bathtub is cold.
- Do not remove a handle by force if a hidden set screw is holding it.
- Do not pull a cartridge unless water shutoff and matching parts are ready.
No-hot-water result map
Run a short tub test and nearby sink test. The result tells you whether to stay at the bathtub valve or leave the bathroom.
- Measure the tub water at the hottest handle setting.
- Measure or feel a nearby sink after the line warms up.
- Note pressure changes as the handle moves toward hot.
| What you see | What it usually means | Next move |
|---|---|---|
| Sink hot, tub cold | Tub valve, limit stop, or cartridge | Inspect behind the tub handle. |
| Sink and tub both cold | Water heater or whole-home supply | Skip tub trim and diagnose hot-water supply. |
| Tub lukewarm only | Limit stop set low or damaged | Check anti-scald stop before cartridge replacement. |
| Hot-side pressure weak or blocked | Cartridge or pressure-balance issue | Match the valve cartridge carefully. |
Check the limit stop before the cartridge
Many tub-shower valves have an anti-scald stop behind the handle. If it is set low, the handle cannot rotate far enough toward hot.
- Remove trim only after the tub is proven to be the only cold fixture.
- Loosen the handle set screw or trim screw by hand.
- Note the original limit-stop position before changing it.
- Move in small increments and retest with a thermometer.
- Replace a stop kit only if it is broken, missing, or will not hold its setting.
- How to Replace a Bathtub Handle Anti-Scald Stop Kit — Use when the limit stop is confirmed damaged or unable to hold adjustment.
- How to Replace a Bathtub Valve Cartridge — Use when the tub valve cartridge is the confirmed hot-side restriction.
When to move beyond the bathroom
If more than one hot fixture is cold, the bathtub valve is not the starting point. A tub-only page should not send you into water-heater work unless the comparison proves it.
- Check whether the kitchen, laundry, or another bathroom has hot water.
- Look for recent water-heater outages, error codes, or shutoff work only when multiple fixtures are affected.
- Do not pull a tub cartridge for a whole-home no-hot symptom.
- Call for help if gas, electrical, or water-heater safety concerns are present.
Tools You May Need
These tools support measurement and careful valve-trim inspection. Skip cartridge tools until the tub is proven as the isolated fixture.
Bath thermometer
Helps when: Use a thermometer to compare tub temperature with a nearby sink before opening the valve trim.
Skip it when: Skip judging by hand feel alone when the tub is only lukewarm.
Compare bath thermometer on Amazon
Screwdriver set
Helps when: Use a hand screwdriver only after the tub is confirmed as the isolated no-hot-water fixture.
Skip it when: Skip trim removal if the whole house has no hot water.
Compare screwdriver set on Amazon
Allen key set
Helps when: Choose this when the handle has a small set screw that must loosen before the limit stop is visible.
Skip it when: Skip forcing a handle that is still held by a set screw.
Compare allen key set on Amazon
Cartridge puller
Helps when: Keep this for a confirmed stuck cartridge on a compatible valve after the trim and shutoff plan are clear.
Skip it when: Skip a puller for a simple temperature-limit adjustment.
Compare cartridge puller on Amazon
Inspection flashlight
Helps when: Use light behind the handle to see the limit stop, retaining clip, brand marks, and corrosion clues.
Skip it when: Skip working inside the valve if you cannot identify shutoffs or the retaining parts.
Compare inspection flashlight on AmazonAs an Amazon Associate I earn from qualifying purchases. Repair Riot may earn a commission at no extra cost to you.
Replacement Parts
These parts match a tub-only no-hot-water branch: limit stop, valve cartridge, or pressure-balance cartridge. Do not buy them for a whole-home water-heater problem.
Anti-scald limit stop kit
Helps when: Buy this only when the handle limit stop is damaged, missing, or cannot hold the corrected hot setting.
Skip it when: Skip it when the no-hot symptom is caused by the water heater or a stuck cartridge.
Compare anti-scald limit stop kit on AmazonTub/shower valve cartridge
Helps when: Choose this when the tub alone stays cold and the cartridge is stuck, clogged, or not moving hot-side water.
Skip it when: Skip cartridge replacement before comparing the tub with a nearby hot sink.
Compare tub/shower valve cartridge on Amazon
Pressure-balance cartridge
Helps when: Use this for compatible single-handle valves when pressure-balancing behavior blocks the hot side.
Skip it when: Skip it until the exact valve model and cartridge shape are confirmed.
Compare pressure-balance cartridge on AmazonAs an Amazon Associate I earn from qualifying purchases. Repair Riot may earn a commission at no extra cost to you.
FAQ
Why does my bathtub have no hot water but the sink does?
That points to the tub/shower valve, usually the limit stop, cartridge, or pressure-balance cartridge.
Why is the bathtub only lukewarm?
A limit stop set too low can prevent the handle from rotating far enough toward hot.
Should I replace the water heater?
Not if nearby fixtures still get hot. A tub-only symptom starts at the tub valve.
Can a cartridge cause no hot water?
Yes. A stuck, clogged, or failed cartridge can restrict hot water while cold still flows.
What is a pressure-balance cartridge?
It is a valve part that balances hot and cold pressure. If it sticks, it can reduce or block hot-side flow.
Do I need a thermometer?
A thermometer is useful because it proves whether the tub is cold, lukewarm, or simply slower to warm.
When should I stop DIY work?
Stop if the valve leaks, the cartridge is stuck, the retaining clip is corroded, or you cannot shut water off.
Can an anti-scald stop be adjusted?
Often yes, but mark the original position, move gradually, and retest carefully to avoid unsafe hot water.
How this page was built
Repair Riot reviewed this page around tub-only hot-water clues: nearby fixture comparison, measured temperature, limit-stop position, cartridge movement, pressure-balance behavior, and whole-home supply boundaries. The source links support water-heating context and leak safety; the troubleshooting sequence is original guidance.
- EPA WaterSense Fix a Leak Week — supports treating repeated fixture drips and hidden moisture as leaks worth finding early.
- EPA WaterSense showerheads — supports checking shower flow and wasted water when tub and shower water split.
- U.S. DOE water heating guide — supports separating whole-home hot-water supply problems from a tub-only valve problem.