4 Common Hot Water System Faults (And How to Spot Them Early)
Is there anything worse than jumping in the shower only to find the hot water’s gone cold? Okay, perhaps it's a first-world problem, but as far as they go, it has to be one of the worst! We just expect everything to always work, and while hot water systems are built to last, they’re not immune to systemic failures. This is especially the case if your system is ageing or under heavy use. That's why recognising the early signs of trouble can help you avoid that dreaded cold shower or washing dishes with cold water. We’ll cover four common hot water system faults, what they mean, and when it’s time to call in a licensed pro.
Your Hot Water Set-Up: Understanding the Basics Before Troubleshooting
Before you start diagnosing issues, it helps to understand what kind of hot water system you’re working with. A tankless system delivers hot water on demand (without the need to store hot water) and is great for energy efficiency, but it can struggle in homes with multiple hot water outlets running at once.
On the other hand, traditional systems with storage tanks can experience sediment build-up (mineral build-up and mineral deposits) over time, which affects water temperature and overall efficiency. Knowing the type and capacity of your system is key to spotting the right faults, and avoiding the wrong fixes. Your first step is identifying whether you have a gas bottle, solar, or electric hot water system.
With that, let's dive into the four most common hot water problems.
1. No Hot Water at All
Let’s just get the worst of them out of the way—no hot shower at all. Just reading that sends a cold shiver down your spine. This is the most obvious (and most frustrating) sign something has gone wrong. You turn on the tap, and all you get is cold water, or no water flow at all. No hot water typically means your hot water system isn't working properly.
Symptoms:
- Cold water from taps or shower, even after waiting
- No sound from the system when it’s meant to be heating
- No water pressure.
Possible Causes:
- Tripped circuit breaker or blown fuse (electric systems) in power supply
- Pilot light out (gas systems)
- Faulty heating elements, broken thermostat or controller used to heat water
- Sign you need a switchboard upgrade
DIY or Call a Pro?
You can check the switchboard for tripped breakers or relight the pilot light if you know how. But if it’s still not working—or you’re not confident—it’s time to call a licensed electrician or hot water specialist. We imagine you want that hot shower back yesterday anyway.
2. Water Leaks from the System
A leaking hot water system doesn’t always gush like a burst pipe. Sometimes, you have to put on your detective hat. It could just be a slow drip or a suspicious puddle that keeps showing up near the hot water tank.
Warning Signs:
- Damp patches or puddles under the tank
- Garden hose or hot water tap not running properly
- Rust streaks or corrosion on the unit
- Hissing or dripping sounds from valves or pipework
Common Leak Sources:
- Pressure relief or temperature relief valves
- Corroded or cracked tank, due to corroded anode rod
- Loose connections, loose inlet, or leaking pipe joints and fittings
- Leaky tank
DIY or Call a Pro?
If you notice water leaking, ignore leaks at your own peril. They can cause serious water damage, rust, toxic mould, and reduced system efficiency. If that's not enough to convince you to take action, leaks also contribute to higher energy bills. If you spot any of the above signs, it’s best to have a professional plumber inspect it before a small leak turns into a big (and expensive) replacement job.
3. Inconsistent Water Temperature
How annoying are those showers where you can never seem to get the right temperature? One minute it’s lukewarm, the next it’s scalding or ice cold. Definitely not what you signed up for first thing on a cold winter's morning. Water pressure regularly inconsistent is enough to drive you bonkers.
Symptoms:
- Water temperature fluctuates randomly during use
- Hot tap water runs out too quickly
- Takes ages for water to heat up again
Possible Causes:
- Sediment build-up in the tank, which interferes with heating elements
- A faulty thermostat not regulating the temperature properly
- Issues with the tempering valve (mixing hot and cold water) or pressure relief valve
DIY or Call a Pro?
If the issue happens occasionally, it could be a one-off. But if it’s frequent, it’s worth getting it checked. A professional hot water service can flush the system, replace the thermostat, or inspect the mixing valve to restore a consistent, comfortable temperature (as well as your sanity).
4. Strange Noises from the Unit
If your noisy hot water system is starting to sound like it's trying to tell you something, it probably is!
Popping, banging, or hissing noises are common signs that not all is fine and dandy down in the water heater tank. Same goes for stinky water.
Symptoms:
- Popping or rumbling sounds during heating element
- Hissing or high-pitched whines
- Hot water running out faster than usual
Possible Causes:
- Sediment build-up overheating and cracking
- A failing heating element struggling to perform
- Air in the system causing bubbles or pressure changes
DIY or Call a Pro?
While a minor flush might help, unusual noises often point to deeper issues. If the sounds persist, especially if they're getting louder (and scarier), call a licensed hot water plumber to avoid long-term damage or a full system breakdown.
When Should You Call a Hot Water Technician?
Whether you have a gas water heater or an electric water heater, knowing how your system works can help you spot problems early. If there's suddenly not enough hot water, it could be due to a faulty thermostat, storage tank corrosion, or even a sediment build-up near the drain valve. Regular DIY maintenance of your hot water unit, like flushing the tank and checking for leaks, can go a long way in preventing breakdowns and keeping your system running efficiently.
Some minor issues, like checking for a tripped breaker or relighting a pilot light, can be safely handled if you consider yourself a handyman (or handywoman). But if you’re dealing with persistent leaks, strange noises, inconsistent temperatures, or no hot water at all, it’s best to leave your broken hot water system to the pros.
Plus, early detection can avoid major repairs or full system replacements, saving you bigger headaches and money. Sometimes it's worth nipping it in the bud and getting that priceless peace of mind.
Need help? Easther Electrical offers reliable, professional hot water system repairs across the region.
Book a professional inspection today to avoid costly breakdowns tomorrow.
Frequently Asked Questions
What is the most common cause of water heater failure?
The most common cause of hot water system problems is sediment build-up inside the tank, especially in areas with hard water. Over time, this reduces heating efficiency, strains the system, and can eventually cause the heating element or tank to fail.
How do hot water systems fail?
Hot water heaters can fail due to corrosion, worn-out components, thermostat issues, or electrical faults. Leaks, inconsistent heating, and strange noises are often early warning signs that something is going wrong.
What are common causes of a water heater not working?
A lack of hot water is often caused by a tripped breaker in an electric hot water system. There could also be a blown fuse, failed thermostat, or extinguished pilot light. In electric systems, heating element failure is also a frequent culprit, while gas systems may struggle with ignition or valve issues.