First Things First…
Before we jump into the noisy stuff, let’s get a quick handle on how these systems tick. Most Aussie homes have either a storage tank system or a continuous flow (instantaneous) system.
Storage tanks heat up water and keep it hot in an insulated tank, usually around 60°C, thanks to Aussie safety rules.
Continuous flow systems heat water on demand, so you only get hot water when you turn on the tap.
Both types can get noisy over time, but the reasons behind the racket can be a bit different. The main culprits? The heating element (for electric systems), burner assembly (for gas), thermostat, pressure relief valve, connecting pipes, and the tank itself.
Oh, and if you’re in Victoria, your hot water system has to meet the Australian Standard AS/NZS 3500 for installation and safety. Knowing this helps you spot when something’s off.
What’s That Noise? Common Hot Water System Sounds and What They Mean
Banging or Hammering
Loud banging or hammering sounds can be downright scary. This is what plumbers call a water hammer, and it’s a sign your pipes are under pressure, literally.
Why it happens: Water hammer strikes when water flow suddenly stops or changes direction, sending a shockwave through your pipes. This can happen if:
- You turn off taps too quickly
- Washing machines or dishwashers shut off their valves fast
- Your home’s water pressure is way too high
- Pipes aren’t properly secured and rattle around
- The cold water inlet valve on your tank is worn out
Got a solar hot water system? Banging could mean it’s overheating or a sensor’s gone rogue. That’s a big deal - don’t ignore it!
How to fix it:
High water pressure? Grab a pressure gauge ( Bunnings has them) and check your pressure. It should be at 500kpa. If it’s higher, get a plumber to install a pressure-reducing valve.
- Loose pipes? Secure them with clamps or brackets, especially the hot water ones.
- Quick-closing valves? Install water hammer arrestors near appliances.
- Solar system issues? Call a pro ASAP. This isn’t a DIY fix.
Hissing or Sizzling
Hear a hissing sound? Stop what you’re doing and check it out, as this could mean a leak or a pressure problem, and that’s nothing to mess around with.
Why it happens:
- Water’s leaking onto hot surfaces (like the heating element in electric systems)
- The pressure relief valve (TPR valve) is letting off steam because of high pressure or temperature
- Condensation dripping onto the burner in gas systems
- Steam escaping from a leak in the tank or fittings
In electric systems, sediment on the heating element can cause hot spots that flash water into steam, making a sizzling noise. This is common and can make your system less efficient.
How to fix it: Persistent hissing isn’t normal. Look for leaks, puddles, or moisture around your system. If you spot a leak, especially with sparking in electric systems, turn everything off and call Ezy-Plumb right away.
The TPR valve is there to keep your tank from exploding, so if it’s constantly releasing water, your system’s running too hot or under too much pressure.
Humming or Vibrating
A low hum or vibration might not seem like a big deal, but it’s your system’s way of saying something’s loose or not quite right.
Why it happens:
- A loose heating element vibrating as water flows around it
- The heating element itself buzzing from the electrical current
- Water pressure changes causing the system to resonate
- Restricted water flow making pipes or valves vibrate
In older systems, the mounting hardware can loosen up, making these noises more common.
How to fix it: If you’re handy and know how to safely turn off the power. Sometimes, adjusting the water flow can help. If the humming sticks around or you notice other issues (like less hot water or higher bills), book a professional inspection.
Ticking or Clicking
A little ticking here and there is normal, but if it suddenly gets loud or constant, it’s time to check things out.
Why it happens:
- Copper pipes expanding and contracting as hot water flows through
- Heat trap devices in the system doing their thing
- Pipes rubbing against framing or other pipes
- Sudden water pressure changes
- The thermostat clicking on and off
If pipes are touching walls or other surfaces, that ticking can get pretty loud.
How to fix it:
- Wrap pipes in foam insulation (easy to find at Bunnings)
- Make sure pipes have enough space where they pass through walls or floors
- Add pipe hangers or brackets to keep things steady
- Check that pipes aren’t rubbing against each other
If ticking comes with water pressure changes or only happens when you use hot taps, adjusting the pressure relief valve might help. If it’s suddenly loud or persistent, call a plumber to check for bigger issues.
Whistling or Screeching
High-pitched whistling or screeching is more than just annoying. It means water flow is restricted, which can wear out your system faster.
Why does it happen?
- The tempering valve or thermostatic mixing valve is blocked or stuck
- Mineral deposits are clogging up pipes or valves
- Inlet or outlet valves aren’t fully open
- The pressure relief valve isn’t working right
Aussie law says all hot water systems need tempering valves to keep water at safe temps (no hotter than 50°C at the tap). When these get gunked up, water squeezes through tiny gaps, making that whistling sound.
How to fix it: Leave this one to the pros. Tempering valves are safety devices, and messing with them can be dangerous. A licensed plumber can replace the valve and make sure your system’s up to code.
Gurgling or Bubbling
Gurgling noises sound odd, but they usually mean there’s air trapped in your system. Not the end of the world, but it’s worth sorting out.
Why it happens:
- Air stuck in the tank or pipes
- Blockages forcing water through tight spots
- Issues with system venting
How to fix it:
- Open the hot water tap that’s furthest from your system
- Let it run until the water flows smoothly (no more sputtering)
If the gurgling keeps up or you notice low hot water pressure, call in a pro. Persistent air could mean there’s a seal problem or an issue with the pressure relief valve.
Don’t Ignore the Signs
Hot water system noises are your home’s way of asking for help. Whether it’s a simple flush or a call to the pros, tackling these sounds early can save you from cold showers and costly repairs. If you’re ever in doubt, don’t hesitate, reach out to a trusted plumber and get your hot water system back to its quiet, reliable self!
Australian Hot Water System Regulations and Safety
Understanding Australian hot water system regulations helps you recognise when your system isn’t operating safely. The key requirements under AS/NZS 3500 include:
Temperature Requirements: Storage tank hot water systems must maintain water at a minimum of 60°C to prevent the growth of Legionella bacteria, which can cause serious illness. However, water delivered to taps must not exceed 50°C to prevent scalding.
Annual Maintenance: Australian regulations recommend annual inspections by licensed plumbers to verify proper temperature control, check safety valves, inspect for corrosion, and replace sacrificial anode rods if corroded.
Licensed Installation and Repairs: In Victoria, all hot water system installation, repairs, and alterations must be performed by licensed plumbers.
Pressure Relief Valve Testing: The temperature and pressure relief valve should be tested every six months by lifting the lever to release a small amount of water.
Need your hot water system serviced to meet Australian Standards? Book your annual maintenance with Ezy-Plumb’s licensed technicians today.
Final Words
Hot water system noises are your system’s way of communicating that something needs attention. While some sounds indicate minor issues requiring simple maintenance, others signal more serious problems demanding immediate professional intervention. Understanding what these noises mean empowers you to respond appropriately, protecting your investment and ensuring your family’s safety and comfort.
Is your hot water system making unusual noises? Contact Ezy-Plumb today for expert diagnosis and repair. Same-day service available across Melbourne’s Bayside suburbs!
