Why is my tankless water heater making a squeaking noise?
An intermittent, high-pitched squeak coming from a tankless water heater is often tied to external factors like recent utility work or internal component issues. This noise makes it difficult to know whether the system requires professional attention or a simple check before calling a plumber.
What the numbers show
Counted from the threads quoted below. How we count
- The most recent one is from October 2026.
- This comes up 16.7× more often in r/Plumbing than across the site as a whole.
What people tried
Every workaround mentioned in the threads below. We haven’t tested any of them — and nobody here is claiming they worked.
Found another way around this?
Share your steps and trade-offs so fellow engineers don't have to reinvent the wheel. No account required.
- 1calling a plumberDid this help you?
- 2Turn it offDid this help you?
- 3Check if the hot valve is open all the wayDid this help you?
- 4Planning on putting up a wall for the utility room that will dampen it going up the stairsDid this help you?
- 5Shutting off the main, draining the lines, and turning it back onDid this help you?
- 6Turning the main valve to 50%Did this help you?
- 7Checking and opening the water heater shut off valve fullyDid this help you?
- 8Flushing the water heater to clear potential sediment buildupDid this help you?
- 9Checking for a blocked discharge lineDid this help you?
- 10Checking if the burner is running while the noise occurs to isolate the causeDid this help you?
In their words
Unedited, grouped by where they were said, most upvoted first within each place, each linked to the thread it came from.
“After we use the shower the water heater kicks in and it creates this loud clicking sound - it’s almost like a really loud light switch.”source ↗
“It appears to be coming from the pipes above the water heater but it’s loud enough we can hear it on the main floor from the basement.”source ↗
“Is this concerning and/or anything we can do about it?”source ↗
“Water heater has begun squeaking (Sounds like a bearing)”source ↗
“Don't know if it's relevant but the city fixed a leaking/broken line near my house today and in the early afternoon I begun hearing a squeak that sounds like a bearing.”source ↗
“It's intermittent. Sometimes it goes longer, other times it stops pretty quick.”source ↗
“I know nothing about plumbing obviously but is there anything I can do to assess it before calling a plumber?”source ↗
“It's a high pitch squeak”source ↗
“It is tankless and you might not be able to see due to all the junk but nothing is obstructing it or leaned against it”source ↗
“Loud whining whenever hot water is flowing. It's really loud from the basement below.”source ↗
“Vanity: whines with the handle at the midpoint. With the cold shut off under the sink and hot only, it still whines and gets louder. Cold only: no noise.”source ↗
“It has been doing this every few hours for two days, started after the HOA turned off the water for a few hours while a repair was taking place outside. The water inside the house is operating normally. Appreciate any help.”source ↗
“My daughter just turned the heater on this morning and heard this banging/knocking noise. It concerned her since she’s in a new place, and we hadn’t heard anything like this before.”source ↗
Where this came up
People with this problem also raised
- 4Why is my boiler making a constant humming noise when heat is on?
- 38Washer making a loud screeching noise during spin cycle
- 2Why does my faucet honk when I close it?
- 5Loud slamming noise when watering system turns on
- 8Why does my toilet make a train noise when I flush?
- 8Why is my plumbing or AC making bubbling noises?