Why Is My Hot Water Not Working? Do I Need a Plumber or a New System?

So your hot water’s stopped working. Great.

Nothing quite like that moment when you’re expecting a nice warm shower and instead get hit with water that feels like it came straight from Antarctica. Makes you want to crawl back into bed and pretend the day hasn’t started yet.

The frustrating thing is, hot water systems don’t usually give you much warning before they fail completely. One day you’re living your best life, the next you’re googling plumbers at all hours of the morning because nobody in your house can have a decent shower.

Common Causes of Hot Water Problems in Homes

So what actually goes wrong with these systems? From experience, the usual culprits are:

• Thermostat malfunction

Your electric hot water system has a thermostat designed to regulate the temperature — heating the water when needed and stopping once it’s hot. If it stops working properly, it may only heat water to lukewarm or fail entirely.

• Burnt-out heating elements

The heating elements can also wear out over time. Once this happens, the system won’t be able to produce hot water again until they’re replaced.

For example, one homeowner I spoke with experienced weeks of only warm water before realising the thermostat was the issue. Once repaired, their system returned to normal.

Sludge build-up at the bottom

All the sediment and minerals in your water eventually settle at the bottom of the tank. Over time, this forms a thick layer that can make it harder for the system to heat water properly. You might even hear strange noises as the tank struggles to work through the build-up.

Gas pilot light issues

Gas systems rely on a small pilot flame to stay lit. If it keeps going out, there’s a problem. It could be a faulty thermocouple, something blocking the gas line, or even a draft. Modern systems often use electronic ignition instead of pilot lights, but those can fail too.

Tank corrosion

Water and metal don’t mix forever. Over time, your tank will start to corrode from the inside out, leading to rusty water, leaks, or both. Once this stage begins, repair usually isn’t an option — replacement is the only solution.

Safety valve faults

Your system has a pressure relief valve that prevents dangerous pressure build-up inside the tank. If the valve stops working correctly, it can put the whole system at risk.

Should You Repair or Replace Your Hot Water System?

This is where things can get tricky. Nobody wants to spend money fixing a system that’s on its last legs, but at the same time, you don’t want to replace it if a simple repair will do.

How old is the system?

If it’s over ten years old and starting to show signs of trouble, replacement is usually the smarter option. Most hot water systems last between 8 and 12 years. Beyond that, repairs often become more expensive and less effective.

Are you constantly calling for repairs?

If you’re needing hot water repairs every few months, that’s a clear sign the system is nearing the end of its life. Ongoing repair costs can quickly add up and may not be worth it compared to a replacement.

Rising energy bills

Older systems are often much less energy-efficient. If you’ve noticed your electricity or gas bills creeping higher, upgrading to a modern, efficient system could save you money in the long run.

Has your household changed?

If your family has grown or your hot water needs have increased, your old system may simply not be able to keep up. In that case, upgrading to a larger or more efficient unit can make life much easier.

Signs It's Time to Call a Plumber

DIY can be great for some household jobs, but hot water systems aren’t something you want to take risks with. Here are the clear signs it’s time to call a professional:

No hot water anywhere

If your system has completely stopped producing hot water, you’ll need professional help. It could be an electrical fault, a gas problem, or a major component failure. Don’t delay — call an emergency plumber.

Strange noises from the tank

Banging, rumbling or popping sounds are not normal. They usually indicate that something inside the tank is on the verge of failing. It’s better to deal with it early before it turns into a much bigger problem.

Discoloured or foul-smelling water 

Rusty water, a sulphur smell or a metallic taste usually mean your tank is corroding from the inside. Once this starts, it’s not something you can fix with cleaning or DIY methods.

Leaks around the system

Any water pooling near your hot water system is a red flag. Even small leaks can quickly escalate into costly damage if ignored.

Fluctuating temperatures

If your water is scalding hot one moment and freezing cold the next, that’s both inconvenient and unsafe. It usually points to multiple faults within the system and needs urgent professional attention.

Hot Water System Maintenance Tips to Avoid Cold Showers

Want to avoid nasty surprises? A bit of maintenance goes a long way:

Get it serviced annually 

Yes, it costs money, but it's way cheaper than emergency callouts or complete system replacement. A decent plumber will spot problems before they become disasters.

Flush the tank yearly 

All that sediment buildup I mentioned? You can get rid of it by draining your tank once a year. 

Test your relief valve 

Every six months, lift the little lever to make sure water comes out and stops when you let go. Takes thirty seconds and could prevent major problems.

Pay attention to changes 

Unusual noises, fluctuating water temperatures or strange smells are all warning signs. Don’t ignore them -  early action can prevent bigger, more expensive problems down the track.

When hot water problems hit, you need someone reliable who won't rip you off. Whether it's emergency plumbing services or hot water installation northern beaches residents can depend on, having a good plumber's number is essential.

Professional general plumbing services can sort out your hot water disasters without the runaround.

Sick of Cold Showers Already?

Hot water always dies at the worst possible moment. Middle of winter, right before guests arrive, when you're already running late. Murphy's law in action.

Don't put up with lukewarm showers or waste money on dodgy repairs. Call Koalafied Plumbing for honest advice and reliable hot water repairs that actually work. We handle hot water installation northern beaches families trust, and we'll tell you straight whether you need repairs or replacement.

Because nobody should have to start their day with a cold shower.