Here’s A Quick Answer
Yes,,hot water heaters / hot water systems can make some noise, especially light clicking or ticking when heating. But popping, banging/knocking, gurgling, buzzing, or constant hissing usually means there’s an issue like scale build-up, pressure changes, a valve problem, or a failing part.
If you’re in Sydney and want it checked, call Fox Electricians on 0416 177 025.
Here’s A Detailed Answer
What Noises Are Usually Normal?
These are typically fine if they’re mild and not getting worse:
Gentle humming (often while heating)
Occasional clicking (thermostat or controls switching)
Soft ticking (pipes expanding as they warm up)
Light water-flow sounds (when taps are running)
Noises That Usually Mean A Problem
If the noise is new, louder, more frequent, or paired with other symptoms, it’s time to investigate.
Popping / Crackling / Rumbling
Most likely cause: sediment buildup in storage tanks.
Minerals collect at the bottom of the tank, and when the element heats, bubbles push through the sediment and “pop”.
Why it matters: reduces efficiency and can shorten the system’s life.
Loud Banging / Knocking
Often caused by:
water hammer (pressure shock in pipework)
loose pipe brackets
high water pressure
sediment shifting in the tank
If it happens when a tap or appliance shuts off, water hammer is a strong suspect.
Hissing
Hissing can be normal briefly, but constant hissing can indicate:
pressure relief valve releasing
a small leak hitting hot surfaces
overheating or pressure issues
If you see water near wiring, treat it as urgent.
Screeching / Whistling
Often linked to:
pressure problems
a partially closed valve
restricted flow through valves or pipework
Buzzing (Especially Electric Units)
A gentle hum is normal, but buzzing can indicate:
a failing relay/contactor
a struggling element
loose wiring (can be dangerous)
heat pump fan motor issues
Red Flags: Turn It Off And Call A Licensed Pro
Get help urgently if you notice:
burning smell
sparks or crackling near electrical covers
circuit breaker tripping
water leaking onto electrical parts
noises plus no hot water or fluctuating temperature
Should You Call An Electrician Or A Plumber?
Call an electrician if you have:
buzzing, burning smells, tripping power
heat marks on switches/cables
heat pump electrical/fan issues
anything involving wiring or isolators
Call a plumber if you have:
relief valve dripping
sediment issues (tank flush)
pressure/valve/pipe hammer problems
rusty/discoloured hot water
If you’re unsure, start with safety: if it involves power, call an electrician first.
FAQs
Do hot water heaters make noise when heating?
Light clicking or ticking can be normal as parts expand and contract. Loud, repeated, or new noises aren’t “normal” and should be checked.
Why is my hot water heater making a popping noise?
Popping is commonly caused by scale/sediment heating up and releasing trapped steam bubbles in the tank.
Why is my hot water heater making a knocking or banging noise?
This can be water hammer, expansion, or pressure changes. It can stress pipes and valves, so it’s worth investigating.
Why is my hot water heater making a gurgling noise?
Often air in the lines, pressure/valve issues, or flow changes — especially if it happens after using multiple taps.
Are heat pump hot water systems noisy?
They can be, because they use a fan and compressor. If it’s installed near bedrooms or windows, it may be noticeable — placement and vibration isolation matter.
Concerned About Noises From Your Hot Water Heater?
If your hot water system is making unusual or loud sounds and you’re not sure whether it’s normal, the licensed team at Fox Electricians can help diagnose the issue and recommend the right solution.
Contact us today on 0416 177 025 for expert advice, repairs, or upgrades you can trust.
