A water heater making noise is not automatically failing. Storage-tank, tankless and heat-pump water heaters can produce normal sounds as water moves, metal expands, burners ignite, heating elements operate, or fans and pumps run.
A new, loud, continuous or worsening sound deserves closer attention—especially when it appears with leaking, poor hot-water performance, unstable temperature, a gas odor, electrical problems or repeated pressure-relief discharge.
Quick answer
Popping or rumbling during heating: Often points to sediment or mineral deposits in a storage-tank water heater.
Banging when a faucet or appliance valve closes: More likely involves water hammer or unsecured plumbing than the tank itself.
Brief ticking, clicking, humming or soft ignition sounds: May be normal when they occur predictably and are not becoming louder or more frequent.
Hissing or sizzling: Can involve element scale, condensation, leaking water or moisture contacting a hot component. The heater type and location of the sound matter.
Noise with leaking, steam, a gas odor, a carbon-monoxide alarm, a burning smell or wet electrical controls: Stop treating it as a routine noise problem and obtain appropriate emergency or professional help.
Quick Water-Heater Sound Decoder
The same sound can come from different parts of the water heater or plumbing system. Use this table as a starting point rather than proof that one particular component has failed.
| Sound | When or where it occurs | Possible causes | Reasonable first response |
|---|---|---|---|
| Popping, rumbling or crackling | Usually while a storage tank is heating | Sediment, mineral scale or another deposit-related condition | Review the maintenance history and determine whether model-appropriate flushing or inspection is needed. |
| Ticking or clicking | During heating, cooling, ignition or water movement | Pipe expansion, heat traps, relays, ignition components or ordinary control operation | Compare it with previous operation and investigate if it is new, unusually loud or paired with another symptom. |
| Banging or knocking | When a faucet or appliance valve closes, or while pipes heat and cool | Water hammer, loose pipes, thermal expansion or tank deposits | Note the timing and have water pressure, piping support and expansion conditions evaluated when persistent. |
| Hissing or sizzling | Near an electric element, gas burner or wet component | Element scale, condensation, an active leak or water contacting a hot surface | Check safely for visible moisture and changes in performance. Arrange service when persistent or associated with leaking. |
| Humming, buzzing or vibration | During element, fan, pump, compressor, blower or burner operation | Normal equipment operation, loose external parts, pipe contact or a component problem | Compare its volume and pattern with normal operation. Do not tighten protected electrical or combustion components. |
| Whistling or screeching | Near a valve, restricted connection, fan or air passage | Restricted flow, a partly closed valve, pressure conditions, or blower and airflow problems | Identify where it is loudest and arrange inspection when the sound is sharp, persistent or worsening. |
| Dripping, running water or gurgling | At piping, a condensate drain, relief discharge or inside the cabinet | Normal condensate on applicable models, an active leak, a drainage problem or ordinary water flow | Locate the water source without opening protected panels or touching wet electrical equipment. |
Start With the Sound’s Location and Timing
The name of the sound alone rarely proves what caused it. “Banging,” for example, can describe water hammer in the pipes, thermal movement near the tank or deposit-related movement inside a storage heater.
A more reliable diagnosis uses five questions:
- What does the sound resemble? Is it popping, rumbling, banging, ticking, hissing, humming, whistling, dripping or something else?
- Where is it loudest? Is it inside the tank, near the top connections, at the lower burner or element area, in nearby pipes, at a valve, or inside a tankless or heat-pump cabinet?
- When does it occur? Does it happen while heating, when a faucet closes, during ignition, after heavy hot-water use, or continuously when no fixture is running?
- What type of heater is installed? Is it a gas storage, electric storage, tankless, heat-pump or point-of-use water heater?
- What other symptoms appear? Is there leaking, inadequate hot water, excessive temperature, pressure change, an unusual odor, an error code or electrical tripping?
Best diagnostic rule: Identify the sound, location, timing, heater type and accompanying symptoms before deciding what the noise means.
Where the Sound Is Loudest
| Sound location | Possible area to investigate | Important limitation |
|---|---|---|
| Inside or near the bottom of a storage tank | Sediment, mineral deposits, heating-element operation, burner operation or condensation | The sound alone does not establish the severity of the buildup or component condition. |
| Top of the heater | Hot- and cold-water connections, heat traps, flexible connectors, valves or pipe expansion | Noise can travel through metal piping and appear to come from the tank. |
| Nearby walls or ceiling pipes | Water hammer, thermal expansion, loose supports or contact with framing | The water heater may not be the source even when the noise occurs during hot-water use. |
| Relief valve or discharge pipe | Thermal expansion, excessive pressure or temperature, valve condition or an installation issue | Never cap, plug or block the discharge pipe. |
| Tankless cabinet | Blower, ignition, water flow, an applicable recirculation pump, heat exchanger, scale or restricted airflow | Compare the sound with the exact model manual and any displayed error code. |
| Heat-pump water heater | Fan, compressor, vibration, condensate system or ordinary water-heating components | Fan and compressor noise may be normal, but new grinding, scraping or rapidly increasing vibration requires investigation. |
If noise is accompanied by inadequate or inconsistent heating, use the separate guide to troubleshoot a water heater that is not producing enough hot water.
Which Water-Heater Sounds May Be Normal?
Some water heaters are not silent during normal operation. The Rheem guide to normal and abnormal water-heater noises explains that sounds such as ticking, humming, water movement and soft ignition can be normal when they occur predictably and are not accompanied by warning symptoms.
A sound is more likely to represent normal operation when it is:
- Quiet or moderate rather than suddenly loud
- Brief and connected to a predictable operating event
- Consistent with how the heater has operated previously
- Not accompanied by leaking, odors, error codes or performance loss
- Consistent with the sound description in the exact model manual
| Potentially normal sound | Possible operating explanation | When to investigate |
|---|---|---|
| Brief ticking or clicking | Metal expansion, heat traps, relay operation or ignition controls | It becomes rapid, loud or continuous, or appears with ignition failure. |
| Quiet electric hum | Heating-element or electrical operation | It changes into loud buzzing, arcing, a burning odor or breaker tripping. |
| Soft ignition or burner sound | Gas ignition and normal burner operation | Ignition is delayed, explosive-sounding, repeatedly unsuccessful or accompanied by a gas odor. |
| Fan, blower or compressor sound | Normal operation of a tankless or heat-pump water heater | Grinding, scraping, severe vibration, fault codes or abnormal shutdown begins. |
| Water-flow or mild gurgling sound | Water movement, condensate drainage or recirculation | It continues with no hot-water demand, is accompanied by visible water or the drain system backs up. |
A previously normal sound can still deserve attention when its volume, duration or pattern changes. Previous operating behavior and the exact manufacturer manual provide important context.
Popping, Rumbling or Crackling From a Storage Tank
Popping and rumbling during a storage tank’s heating cycle are commonly associated with sediment or mineral deposits. Deposits can settle near the bottom of the tank or collect around an electric heating element. Water heating and moving around those deposits can create popping, crackling or rumbling sounds.
The A. O. Smith technical bulletins for noisy water heaters address mineral buildup separately from water hammer, heat-trap noise, condensation and other conditions. They also identify aluminum hydroxide deposits as a less-common possible cause of popping or crackling under certain water and anode-rod conditions.
Signs That Support a Sediment Diagnosis
Sediment becomes a more plausible explanation when:
- The heater is a conventional storage-tank model
- The noise occurs mainly while the burner or heating elements are operating
- The home has hard or mineral-rich water
- The tank has not been flushed according to its model-specific maintenance guidance
- Hot-water recovery or usable capacity has gradually declined
- Visible sediment appears in water appropriately drained from the tank
Learn more about the causes and symptoms of sediment buildup inside a water heater.
Does Rumbling Mean the Tank Must Be Replaced?
No. Rumbling alone does not prove that a tank has suffered irreversible damage or reached the end of its service life. The appropriate response depends on the heater’s maintenance history, age, water quality, tank condition and whether the sound improves after appropriate service.
A model-appropriate tank flush may remove loose sediment, but it will not repair:
- A leaking tank shell
- Hardened scale attached to an element or internal surface
- A damaged heating element
- Water hammer in the building’s pipes
- A pressure or thermal-expansion problem
- A burner, blower, valve or control fault
Before arranging the work, review what affects the typical cost of flushing a water heater. Do not assume that every noisy heater should be flushed without first confirming the likely sound source and checking the exact model instructions.
If the noise appears with water around the base or connections, use the separate guide to identify where the water heater is leaking. A leak from a fitting or valve is different from water leaking through the tank body.
Ticking and Clicking Sounds
Brief ticking or clicking can result from ordinary expansion and contraction as piping and metal components warm and cool. Heat-trap fittings, check valves, relays and ignition controls can also make clicking sounds during normal operation.
Ticking Near the Top Connections
When the sound is loudest at the inlet or outlet connections, possible explanations include:
- Heat-trap components moving as water flows
- Metal connectors expanding during heating
- Pipes rubbing against framing, clips or nearby materials
- A check valve or another flow-control component operating
A brief, repeatable tick during heating may not require repair. Investigate when it becomes loud or constant, or when it is accompanied by leaking, visible pipe movement or pressure-related symptoms.
Clicking From a Gas or Tankless Heater
Gas-fired and tankless heaters may click during an ignition sequence. The sound becomes more concerning when the heater repeatedly attempts to ignite, shuts down, displays an error code or fails to produce hot water.
Do not open a burner compartment or alter ignition components as part of a general noise check. Follow the exact model manual and obtain qualified service when ignition is delayed, unreliable or abnormal.
Banging or Knocking: Tank Noise or Water Hammer?
The timing of a bang is usually more useful than its volume.
Bang When a Faucet or Appliance Valve Closes
A bang that occurs immediately when a faucet, washing machine, dishwasher or another fast-closing valve stops water flow may indicate water hammer. Moving water stops or changes direction rapidly, creating a pressure wave that can move pipes or cause them to strike nearby framing.
Possible contributing conditions include:
- Fast-closing fixture or appliance valves
- High or unstable water pressure
- Loose or inadequately supported piping
- A missing, ineffective or incorrectly located water-hammer control
- Recent changes to the plumbing system
Do not assume that installing an arrestor is always the complete solution. A plumber may need to evaluate water pressure, pipe support, valve behavior and the location where the pressure wave begins.
Knocking While the Heater Warms Up
Knocking or ticking that develops gradually during heating may involve:
- Thermal expansion of hot-water piping
- Pipes sliding against framing or supports
- Heat-trap or check-valve movement
- Sediment-related movement inside a storage tank
- Expansion conditions in a closed plumbing system
Noise caused by thermal movement may be more noticeable when the heater starts after a long idle period. A professional can distinguish ordinary expansion from excessive pressure or inadequate pipe support.
Banging With Relief-Valve Discharge
Banging accompanied by water discharging from the temperature-and-pressure relief valve, commonly called the T&P valve, requires a broader pressure and temperature evaluation. Possible causes include closed-system thermal expansion, excessive supply pressure, overheating, valve contamination or another installation problem.
Do not cap, plug or block a relief-valve discharge pipe. Avoid contact with discharged water because it may be hot enough to cause a scald injury.
Hissing or Sizzling: Electric and Gas Causes Differ
Hissing and sizzling require the sound location and heater type to be identified. The same description can refer to mineral scale on an electric element, condensation near a gas burner, leaking water or ordinary component operation.
Electric Water Heater Hissing
Possible electric-water-heater explanations include:
- Mineral scale surrounding a heating element
- A heating element producing louder-than-normal operating noise
- Water leaking from an element gasket
- Moisture contacting a hot component
- An electrical buzz being described as a hiss
A quiet operating sound may be normal for some models. A loud, new or increasing hiss deserves inspection, particularly when hot-water performance has declined or moisture appears near an access panel.
Do not remove an electric water heater’s access panels merely to identify a sound. These compartments can contain high-voltage components.
Gas Water Heater Sizzling
On a gas storage heater, a brief sizzling sound may occur when condensation forms during a heating cycle and reaches a hot burner-area surface. Condensation may be more noticeable when a cold tank begins heating or during heavy recovery demand.
Persistent sizzling can also mean that water is leaking onto a hot component. Check from a safe position for visible moisture around:
- The cold- and hot-water connections
- The T&P valve and discharge piping
- The drain valve
- The lower tank area
- Nearby plumbing above the heater
Do not reach into the burner compartment or continue operating a gas appliance when a gas odor is present.
If you smell or hear leaking gas
The U.S. Consumer Product Safety Commission’s gas-leak guidance advises leaving the building immediately.
Do not operate lights, electrical switches, phones or appliance controls inside. Contact the gas supplier or emergency services from a safe location outside the building.
Humming, Buzzing or Vibration
A quiet hum may be part of normal water-heater operation. A loud, new or increasing buzz or vibration can instead involve pipe contact, an external panel, a pump, a fan, a compressor, a blower or an electrical component.
The heater type, sound location and timing help separate expected equipment operation from a developing problem.
Electric Storage Water Heaters
Electric heating elements, thermostats and relays can produce mild humming or clicking sounds during a heating cycle. Further inspection is appropriate when the sound becomes unusually loud or appears with:
- A burning odor
- Crackling or arcing sounds
- Repeated circuit-breaker tripping
- Water near an electrical access panel
- Reduced or inconsistent hot-water output
Do not remove electrical access panels merely to locate a sound. Residential electric water heaters commonly contain energized 120- or 240-volt components, and moisture around those areas increases the risk.
Tankless Water Heaters
A tankless water heater may produce brief ignition clicks, blower or fan noise and the sound of water moving through the heat exchanger. Models equipped with an internal recirculation pump may also hum while the pump operates.
Some gas tankless models continue running a blower briefly after hot-water demand ends as part of a normal post-purge cycle. Investigate when the sound:
- Changes into grinding, scraping or severe vibration
- Continues well beyond the unit’s normal post-purge period
- Appears with an error code or repeated shutdown
- Occurs during repeated unsuccessful ignition attempts
- Appears with reduced flow or unstable water temperature
Compare tankless sounds with the operating and troubleshooting information for the exact model. Error codes and the timing of the sound are often more useful than the sound name alone.
Heat-Pump Water Heaters
Heat-pump water heaters use a fan and compressor, making them more audible than conventional electric storage tanks. A steady fan, airflow or compressor sound may be normal during heat-pump operation.
Potential warning signs include:
- Grinding or scraping from the fan area
- Severe cabinet vibration
- A sudden increase in operating volume
- Frequent cycling that differs from normal operation
- A blocked, leaking or overflowing condensate system
- Fault codes or unexpected shutdown
Operation of backup electric resistance elements is not automatically a fault. It may occur because of the selected operating mode, high hot-water demand, low surrounding temperature or a model-specific control strategy.
Pipes, Pumps and External Vibration
A vibration that seems to come from the heater may actually be transmitted through connected piping. Possible areas to examine include:
- Pipes or flexible connectors touching the cabinet
- Pipes contacting wall framing or metal supports
- Loose external covers or service panels
- A recirculation pump transmitting vibration into the piping
- Improper support of connected plumbing components
Do not tighten electrical, gas, combustion or pressurized plumbing components simply because they appear to be vibrating. Confirm the actual source first.
Whistling, Screeching or Singing Sounds
A high-pitched whistle, screech or singing sound often suggests that water or air is moving through a restricted opening. The source can also be a fan, blower, pump or electric heating element.
Possible causes include:
- A partly closed water-supply valve
- A restricted connection or fitting
- High or unstable water pressure
- A pressure-reducing valve or flow-control problem
- Mineral scale restricting a tankless heat exchanger
- A noisy electric heating element
- A blower or fan problem
- An air-intake or vent restriction on an applicable gas model
Do not diagnose a whistle by turning random valves. A nearby control could be a gas valve, safety device or heater-isolation valve. Identify the component and its purpose before any adjustment is made.
A brief water-flow sound may not require repair. A sharp, continuous or worsening screech—particularly when paired with low flow, pressure changes, overheating or an error code—should be professionally evaluated.
Dripping, Running Water or Gurgling Sounds
These sounds can represent normal water movement, condensate drainage or an active leak. The first task is determining whether visible water is present and where it originates.
Possible Normal Sources
- Condensate draining from a condensing tankless water heater
- Condensate produced by a heat-pump water heater
- Water movement while a storage tank refills or recovers
- A hot-water recirculation system operating
- Brief condensation near a gas burner during a heating cycle
Sources That Need Investigation
- A plumbing connection dripping onto the heater
- A leaking drain valve
- A leaking electric-element gasket
- A blocked or disconnected condensate drain
- Water discharging from the temperature-and-pressure relief valve
- Water leaking through the storage-tank body
- A running-water sound continuing when no fixture or recirculation system is operating
Do not touch the water heater when water has reached wiring, controls or an electrical access area. Keep away from the wet equipment and obtain appropriate professional assistance.
Relief-Valve Noise and Water Discharge
The temperature-and-pressure relief valve, commonly called the T&P valve, is an emergency safety device. Activity at the valve or discharge pipe may sound like dripping, hissing, flowing water or a sudden release.
Rheem Technical Bulletin 1220 on temperature-and-pressure relief valves describes T&P valves as emergency safety limit devices intended to relieve excessive temperature or pressure. The valve should not be treated as an ordinary drain, shut-off or pressure-control device.
Possible reasons for discharge include:
- Thermal expansion in a closed plumbing system
- Excessive incoming water pressure
- Water overheating
- A worn, contaminated or damaged relief valve
- An expansion tank that is missing, incorrectly charged, undersized or no longer functioning
- An installation or discharge-piping problem
Never cap, plug, clamp or block a T&P discharge pipe.
Keep away from discharged water because it may cause a serious scald injury. Continuous, forceful or unusually hot discharge requires prompt professional diagnosis.
The valve itself may require replacement, but replacing it without identifying why it opened can allow the problem to return. Review the warning signs and factors affecting water heater pressure-relief valve replacement cost.
Thermal Expansion in a Closed Plumbing System
Water expands as it is heated. In a closed plumbing system, a check valve, backflow preventer or pressure-reducing valve without an effective bypass may prevent expanded water from moving back toward the public supply. System pressure can then rise during the heating cycle.
An expansion tank provides space for the increased water volume, but it must be properly selected, installed and charged for the plumbing system. Learn when one may be needed and what affects water heater expansion tank cost.
A relief valve that drips during nearly every heating cycle may suggest thermal expansion, but the discharge pattern alone does not prove the cause. Supply pressure, water temperature, valve condition and the expansion-control equipment should all be evaluated.
When Flushing or Descaling May Help
Storage-tank flushing and tankless descaling are different maintenance procedures. Neither one fixes every noise.
| Procedure | Common application | What it may address | What it will not repair |
|---|---|---|---|
| Storage-tank flushing | Conventional tank water heaters | Loose sediment collected inside the tank | Water hammer, a leaking tank, damaged elements, pressure problems, ignition faults or hardened scale bonded to components |
| Tankless descaling | Tankless heat exchangers when specified by the manufacturer | Mineral scale restricting water flow or heat transfer | Blower faults, ignition problems, damaged pumps, vent restrictions, plumbing water hammer or leaking components |
Follow the maintenance procedure and approved materials specified for the exact model. A heater with an unknown maintenance history, visible corrosion or an active leak should be assessed before service because the noise may come from deterioration or a failed component rather than loose sediment.
Water-Heater Noise That Requires Immediate Attention
The sound itself is only one part of the risk. These combinations require prompt action:
- A carbon-monoxide alarm or possible CO symptoms: Move outside to fresh air immediately and call emergency services.
- A gas odor: Leave the building and contact the gas supplier or emergency services from outside.
- Steam, apparent boiling or violent internal movement: Keep away from the heater and obtain emergency professional assistance.
- Continuous or forceful T&P discharge: Do not block the discharge and avoid contact with the water.
- Water around electrical controls: Do not touch the heater or wet electrical equipment.
- A burning smell, arcing or loud electrical crackling: Treat the situation as an electrical hazard.
- Flame outside the intended burner area, soot or scorch marks: Stop operating the appliance and obtain qualified assistance.
- A leak through the storage-tank body: The tank itself may have failed.
The U.S. Consumer Product Safety Commission’s carbon-monoxide guidance advises moving outside to fresh air immediately and calling 911 when carbon-monoxide poisoning is suspected.
Homes with fuel-burning appliances should have working carbon-monoxide alarms installed and maintained according to applicable safety guidance and the alarm manufacturer’s instructions.
Should a Noisy Water Heater Be Repaired or Replaced?
Noise alone does not determine whether replacement is necessary. A newer heater can suffer a serious tank failure, while an older heater may only need a limited component repair or plumbing correction.
| Repair may be reasonable when | Replacement becomes more reasonable when |
|---|---|
| The noise has a specific repairable cause, such as a valve, pump, element or pipe-support problem. | Water is leaking through the storage-tank body. |
| The tank and major components are otherwise in sound condition. | Internal corrosion, rusty water and repeated leaking indicate broader deterioration. |
| The heater remains covered by a useful parts or tank warranty. | The unit has experienced repeated failures or requires several major repairs. |
| Hot-water delivery returns to normal after the confirmed problem is corrected. | Noise is accompanied by unreliable heating, severe corrosion or major performance decline. |
| The repair cost is proportionate to the heater’s condition and expected remaining service life. | The repair approaches the cost of a suitable replacement or required parts are unavailable. |
The A. O. Smith repair-or-replace guide considers age together with leaking, inadequate hot water, erratic operation and overall heater condition. Age is useful context, but it should not be treated as an automatic replacement rule.
When replacement is being considered, compare the complete scope of work rather than only the appliance price. Review the factors affecting water heater replacement cost.
What a Professional May Inspect
A proper noise diagnosis may include more than listening to the appliance. Depending on the system, a professional may inspect or test:
- The sound’s location, timing and operating conditions
- Evidence of sediment or mineral scale
- Electric heating elements, thermostats, relays and wiring
- The gas burner, ignition system and combustion condition
- Vent, blower and combustion-air pathways
- Tankless error codes and operating data
- Heat-pump fans, compressors, filters and condensate systems
- Static and flowing water pressure
- Thermal-expansion control
- The T&P valve and discharge piping
- Pipe supports, heat traps, check valves and water hammer
- Recirculation pumps and related controls
- Leaks at fittings, valves, gaskets and the tank body
Record the Noise Before Requesting Service
An intermittent noise may stop before a professional arrives. A short record can make diagnosis easier without requiring hazardous disassembly.
- Record a short audio or video from a safe distance.
- Note the date and time.
- Record whether hot water was running.
- Note whether the heater appeared to be actively heating based on its display, indicator, fan, burner sound or normal operating pattern.
- Photograph any error code or warning light.
- Note whether the sound began when a faucet or appliance valve opened or closed.
- Record any leaking, pressure change, odor or temperature problem.
- Note whether recent maintenance changed the sound.
Do not remove safety covers, enter a burner compartment or reach near wet electrical components merely to obtain a recording.
After Maintenance or Repair, Check the Result
| Result | What it may mean |
|---|---|
| The abnormal noise stops and performance is normal | The identified cause was likely corrected. Continue normal monitoring and maintenance. |
| The noise becomes quieter but remains | Some remaining sound may be normal, or more than one noise source may have been present. |
| The same noise returns quickly | The original cause may not have been fully corrected, or a system condition may be recreating it. |
| The noise stops but heating remains poor | A separate heating, control, capacity or plumbing problem may still require diagnosis. |
| A different sound begins | Record its location and timing instead of assuming it has the same cause as the original noise. |
Frequently Asked Questions
Is a noisy water heater dangerous?
Not always. Quiet humming, brief clicking, water movement and normal fan or burner operation may be expected. A sound becomes more concerning when it is new, loud, worsening or accompanied by a gas odor, carbon-monoxide alarm, leaking, steam, overheating, electrical problems or relief-valve discharge.
Will flushing stop a water heater from popping?
Flushing may reduce popping caused by loose sediment in a storage tank. It will not correct water hammer, a leaking tank, hardened element scale, pressure problems, burner faults or damaged electrical components.
Why does my water heater bang when I turn off a faucet?
A bang that occurs immediately when a faucet or appliance valve closes often points to water hammer or pipe movement. Water pressure, fast-closing valves, pipe support and expansion conditions may all need to be considered.
Why does the water heater make noise when no hot water is running?
Possible explanations include a heating or recovery cycle, a recirculation pump, normal tankless post-purge, pipe expansion, condensate drainage, a leak, relief-valve discharge or a control problem. Note whether the sound stops when the normal operating cycle finishes.
Is tankless water-heater clicking normal?
A brief click during ignition can be normal. Repeated clicking with unsuccessful ignition, shutdowns, error codes, a gas odor or no hot water requires further diagnosis.
Why does my water heater sound like boiling water?
Popping or rumbling caused by sediment can resemble water boiling inside a storage tank. The sound does not automatically mean the tank is actually boiling. Steam, violent movement, overheating or forceful T&P discharge should be treated as urgent warning signs.
Should a noisy 10-year-old water heater be replaced?
Not solely because of age or noise. Consider whether the tank is leaking, whether corrosion is present, what caused the sound, the repair history, warranty status, parts availability, energy performance and the total repair cost.
Bottom Line
A water heater can hum, click, tick, gurgle or produce other predictable sounds during normal operation. The important warning signs are changes: a sound that is new, louder, continuous or paired with leaking, overheating, a gas odor, electrical trouble, pressure discharge, error codes or loss of hot water.
Diagnose the complete pattern—sound, location, timing, heater type and accompanying symptoms—before choosing maintenance, repair or replacement.