Symptom guide
Water heater noises: match the sound and timing
Banging at ignition, popping during recovery, humming electrical parts, and water-flow noises point to different systems and risks.
Safety first: Shut the heater down for a burner bang, electrical buzzing at the panel, smoke, or a noise accompanied by gas odor or leaking water.
Start here
Identify the unit before following a procedure
Photograph the rating plate, control or display, and the exact symptom. Model generations can use different controls and code meanings even when the brand name is the same.
- Choose the heater typeGas tank, electric tank, tankless, heat pump, indirect, or RV.
- Record the exact clueCode, flash count, leak location, sound, or timing.
- Use the closest guideConfirm every model-specific step against the label or manual.
Gas
2 guidesWater Heater Exhaust Blower Noise
A squeal or grind from a power-vent blower usually means a failing bearing or condensate in the housing. When to stop running the heater.
GasWater Heater Made a Loud Bang? Stop
A loud bang from a gas water heater usually means delayed ignition. Why it should be shut down, and how to tell it from sediment or pipe noise.
Electric
2 guidesHeat Pump Water Heater in a Garage, Closet, or Basement?
Compare garage, closet, basement, laundry-room, attic, and outdoor HPWH locations by air, temperature, drainage, noise, and service access.
ElectricWater Heater Breaker Buzzing? Leave It Off
A buzzing water heater breaker can mean a loose connection, a failing breaker, or overload. Why it should stay off until an electrician checks it.
Tankless
6 guidesNavien Knocking Noise: What It Means
Distinguish when a Navien knocks: during ignition, water flow, or heating. Record the pattern and recognize when the unit needs service.
RinnaiRinnai Humming Noise: What It Means
A Rinnai hum may involve normal operation, a fan, or a circulation pump. Note when the sound changes and when professional diagnosis is needed.
TakagiTakagi Tankless Vibration Under Fire
A Takagi that rattles while firing is usually scale in the heat exchanger, the combustion fan, a recirculation pump, or rigid mounting.
TanklessTankless Water Heater Banging? Shut It Down
A banging tankless can mean delayed ignition, scale boiling in the heat exchanger, or water hammer. How to tell which, and when to shut it down.
TanklessTankless Water Heater Clicking Noise
A clicking tankless is usually ignition spark, a gas valve solenoid, a relay, or a check valve. When clicking with no flame means stop.
TanklessTankless Water Heater Groaning Noise
A groaning tankless is usually scale in the heat exchanger, a dry condensate trap, or a failing fan bearing. How to identify the sound.
Troubleshooting
12 guidesAO Smith Water Heater Humming Noise
An A. O. Smith humming can be a transformer, element, gas valve solenoid, or hybrid compressor. Match the sound to when it happens.
TroubleshootingBrand-New Water Heater Making a Popping Noise
Day-one popping is air, pipe expansion, delayed ignition, or debris — not a 12-year tank. Name the sound.
TroubleshootingHybrid Water Heater Noise: What It Means
Hybrid noise is the compressor, fan, check valve, or a failing pump — not tank kettling. Name the sound.
SuperStorSuperStor Indirect Heater Problems Fix
SuperStor no-heat, leaks, and popping have a short list: aquastat, boiler priority, coil air, or a dead tank. Know when to stop DIY.
TroubleshootingWater Heater Buzzing Noise: What It Means
A buzzing water heater may be a transformer, element, gas valve solenoid, blower, or the breaker. How to identify the source and what it means.
TroubleshootingWater Heater Clunking Sound: What It Means
A clunking water heater is often a check valve, recirculation pump, broken dip tube, or tankless diverter. How to tell it from other noises.
TroubleshootingWater Heater Hissing After a Shower?
Hiss after a shower is sediment on the element or burner, a simmering T&P, or steam from a dry-fire. Not normal.
TroubleshootingWater Heater Making a Gurgling Noise?
A gurgling water heater usually means air, condensate in a trap or vent, a lifting T&P valve, or sediment. How to identify the sound.
TroubleshootingWater Heater Making a Hissing Noise?
A hissing water heater can mean sediment, a simmering T&P, steam from a leak, or a gas leak. How to tell which, and when to shut it down.
TroubleshootingWater Heater Sounds Like Rocks Inside
Rocks or popcorn sounds in a tank heater are usually sediment on the tank bottom. When noise is harmless and when it signals a failing tank.
TroubleshootingWater Heater Sounds Like Running Water
A water heater that sounds like running water with taps closed may be discharging its T&P, running recirculation, or leaking. How to find it.
TroubleshootingWater Heater Ticking Like a Clock?
A clock-tick is pipe expansion, a recirc check valve, or tankless post-purge — not harmless. Name the tick.