Why is only one tap losing hot water?
A single tap losing hot water while other fixtures work normally is usually caused by a faulty anti-scald cartridge, a blocked cartridge valve, or an internal obstruction in that specific faucet. This restricts the hot water supply line, preventing you from getting a full, continuous flow of hot water from that specific fixture.
What people tried
Every workaround mentioned in the threads below. We haven’t tested any of them — and nobody here is claiming they worked.
- 1Cleaning or replacing the mixer valve cartridge
- 2Testing the hot water line by removing the mixer valve and turning the water back on
- 3Checking temperature at other faucets like the kitchen after the tub goes cold to test boiler response.
- 4Adjusting the screw on the mixing valve
- 5Adjusting the red piece with the +/- markings
- 6Taking out the cartridge and flipping it 180 degrees
- 7Calling a professional plumber
- 8Restarting the unit
- 9Turning off the gas supply
In their words
Unedited, most upvoted first, each linked to the thread it came from.
“My basement shower never gets hot despite having hot water piping.”source ↗
“Sink in the bathroom does get hot water to it, as well as every other faucet and shower in my home.”source ↗
“The hot water finally stoped coming out 2 days ago, but it was working/not working intermittently for about a week.”source ↗
“Its just this one hot side of the tap that's the issue.”source ↗
“EXCEPT for the tub. The tub and shower do not share fixtures. For some reason, I can only get about a gallon of hot water before it drops to lukewarm when I try to fill the tub.”source ↗
Where this came up
People with this problem also raised
- 2Why does my hot water stop when the sprinklers run?
- 3Why is there no water pressure after changing a faucet?
- 2Kitchen faucet sprayer leaks only when turned on
- 2Why are my cold taps running tepid after a water heater service?
- 3Kitchen faucet won't turn off after water outage
- 4Why is my steam shower outlet constantly leaking water?