Why Is Your Hot Water System Making Noise?

Hot water system making noise? Stressing about it? You’re not alone.

It could be:

• Banging
• Hissing
• Gurgling
• Even beeping!

A noisy hot water system is definitely something no homeowner should ignore. Why? Because even the most reliable systems can start making a racket when something isn’t quite right – and knowing what those noises mean is the first step to solving the issue.

Let’s take a deeper dive:

From safety concerns to simple wear and tear, noisy hot water systems can be a warning sign of problems ranging anywhere from minor to serious.

In our exclusive guide, our intention is to walk you through the most common types of hot water noises:

• What they could mean
• What you should do next?

Why is your hot water system noisy?

Before getting to the specific sounds you’re hearing, let’s talk about why a noisy hot water system happens in the first place.

So what’s the answer?:

Well, most hot water systems are designed to be quiet – so if you’re hearing sounds, it usually means one of the following:

• Sediment build-up in the tank
• Loose pipes or fittings
• Pressure problems
• Faulty valves or thermostats
• Electrical or gas component issues
• Water hammer (sudden pressure shocks).

It doesn’t matter if you’re using an electric, gas, solar, or heat pump system – strange noises are always worth checking out. It might not always mean disaster, but those noises are almost never harmless!

Common hot water system noises & what they mean

Below, we’re going to break down the most common hot water-related noises you are likely to hear – and what they typically mean. Hearing any of these sounds in your Brisbane home?:

1. Hot water heater making noise when water is off

Hot water heater making noise when water is off? It’s probably due to internal pressure build-up or sediment at the bottom of the tank being heated and shifting. In electric systems, it could also be a faulty heating element.

This sound often presents as a popping or crackling noise – and while it may not seem urgent, over time it can reduce the efficiency and lifespan of your unit. A professional hot water system flush might be all that’s needed.

2. Hot water tap makes noise when turned on

If your hot water tap makes noise when turned on, you’re probably hearing what we plumbers call ‘water hammer’. It happens when fast-moving water suddenly stops or changes direction, creating a banging or thudding sound in the pipes.

It can be caused by:

• Loose pipes
• Worn washers
• High water pressure
• Faulty tap fittings.

If you don’t deal with any of this, the constant pressure shock can devastatingly damage your pipes and joints. Installing water hammer arrestors or adjusting the pressure valve can sometimes resolve it, but make sure to consult with a fully-licensed plumber.

3. Hot water heater making noise like running water

Are you hearing what sounds like trickling or flowing when there’s no tap on at all?

A hot water heater making noise like running water is maybe a sign of a hidden leak – either internally or somewhere along your pipework.

Other possible causes include:

• Valve faults
• A cracked tank
• Issues with the pressure relief valve.

No matter what’s gone wrong, running water sounds should never be ignored. It’s well worth having a licensed plumber assess your system immediately to avoid water damage.

4. Hot water system making a knocking noise

A hot water system making a knocking noise can be alarming, stressful, and disruptive, especially if it sounds like the tank is about to burst and it’s midnight!

There’s good news – it’s probably just sediment. When heated, sediment trapped at the bottom of the tank can shift suddenly, causing loud banging or knocking.

Other possible culprits include:

• Loose pipe brackets
• Air in the system
• Expansion and contraction from heat.

Remember, sediment can be flushed out with regular maintenance, but ongoing knocking can really damage those expensive internal parts if you leave it for too long.

5. Why is my gas heater making noise?

Oh, that’s a good question – one we hear quite a lot lately! Why is my gas heater making noise? If you’re asking, others like you especially ask about noises during startup, or in the heating cycles? In most cases, it’s either:

• A delayed ignition (gas igniting after a small build-up)
• Burner issues
• Dirty pilot light or orifices
• Gas pressure problems.

These kinds of sounds might include loud WHOOSHES or BOOMS when the unit fires up! But be aware: These are SERIOUS issues that should always be checked by a gas-licensed technician as soon as possible. Safety first!

6. Why is my hot water system beeping?

Got a beeping system for your hot water? Oh dear – it’s definitely trying to tell you something. Wondering why is my hot water system beeping? It’s probably due to:

• A system error
• A faulty sensor
• Low water pressure
• Electrical issues.
• Maintenance alerts (if you have a newer system).

What should you do? Check your system’s manual. It may provide specific codes or warnings. No luck? Give your local plumber a call to avoid system failure or damage.

7. Hissing or sizzling sounds

Hearing hissing from your hot water system? It can be alarming, so here’s what it could be:

• Water leaking onto hot components
• Overheating inside the tank
• Valve faults.

None of these are good! Sizzling can indicate that water is escaping where it shouldn’t. But no matter the noise, it can all lead to much, much bigger problems – and in some cases, it may even be a fire or fatality risk if electrical parts are anywhere nearby.

8. Gurgling or bubbling sounds

It sounds like you’re dealing with trapped air or sediment. If you’ve recently refilled the system, it’s probably just air working its way out! But if those sounds persist, hot water system flushing may be necessary to remove build-up at the bottom of the tank.

What to do about noisy hot water systems

Wondering what else may help? We’ve put our heads together and come up with these easy, practical steps to take:

Check your user manual: If your system is beeping or flashing, refer to the troubleshooting guide first.

Flush the tank: Sediment is a major cause of noise and can usually be flushed out (especially in electric systems).

Inspect fittings: Loose pipes, taps, or valves might need adjusting or replacing.

Call a professional: If you’re unsure or dealing with gas/electric components, always bring in a licensed Brisbane hot water plumber.

When noise means it’s time to replace

Sometimes, strange sounds are a warning sign that your hot water system is on its way out. Consider a replacement if:

• Your system is more than 10 years old
• You’ve had frequent repairs
• Noise is accompanied by leaks or rusty water
• Your hot water runs out too quickly.

Upgrading to a modern, efficient, next-level system can reduce bills, improve performance, and stop the noise for good!

Need more help with a noisy hot water system?

Is your hot water heater keeping you up at night? Is it stressing you out? Don’t wait.

The friendly, expert, experienced, friendly team at S&J Hot Water Brisbane quickly diagnoses the issue, carries out professional hot water repairs, or recommends a hot water replacement and installation – if it’s needed.

From strange sounds to full-scale servicing, we offer:

• Fast
• Honest
• Affordable hot water support across Brisbane Northside, Brisbane Southside, Logan, Redland Bay, and Moreton Bay.

With our multiple decades of experience, upfront pricing, and expert knowledge, we’re always here to keep your hot water system running smoothly – and quietly.

Reach out to S&J Hot Water Brisbane today – and let’s silence those hot water system problems for good!