There is a particular kind of morning where you step into the shower, and nothing warm turns up. It usually happens on a weekend, and it rarely comes out of nowhere.
Hot water systems usually give you warning before they quit. This guide covers what those warnings look like, what your options are, and what a good plumber should be doing.
Key Takeaways
- Rusty water, odd noises and lukewarm showers are early warning signs.
- A rising energy bill can mean your system is struggling, not that prices went up.
- There are four main types of hot water systems, and they suit different homes.
- Get your system serviced every five years.
- A new unit should come with a Certificate of Compliance, so ask for one.
- Plumbers do the installation, with an electrician only for the power side if needed.
Signs Your System Is on the Way Out
Most systems complain for a while before they stop. Showers that run hot then cold, weaker pressure, or rusty discoloured water all suggest the unit is getting old on the inside.
Look at it as well as listen to it. Water pooling around the base, rust on the outside, and noises like hissing, clunking, or banging are all worth a phone call.
Your Energy Bill Is a Clue
If your gas or electricity bill keeps creeping up and nothing else has changed, the hot water system is a fair suspect.
A struggling unit burns more energy than a healthy one, so the cost climbs before the hot water disappears.
Hot water is a big chunk of home energy anyway. O’Shea Plumbing puts it at around 23% of a home’s greenhouse gas emissions and 25% of total energy costs.
Should You Repair It or Replace It?
Nobody can answer that over the phone, because it depends on how old the unit is, what has actually gone wrong, and whether the system still suits your household.
Any search for hot water repairs Melbourne should end with someone coming out to look at it rather than a number quoted sight unseen.
O’Shea Plumbing has worked on Melbourne homes since 1978 and handles brands including Rheem, Aquamax, Rinnai, Stiebel Eltron and Vulcan.
A technician checks the system and then lays out your choices, from a simple repair through to a full replacement.
The Four Types of Hot Water Systems
Storage Systems
This is the tank most people picture when someone says hot water system. Water sits hot inside an insulated tank, heated by either a gas burner or an electric element.
Gas versions usually keep a small pilot flame burning all the time. Because heat escapes through the tank walls, the unit has to fire up regularly just to keep the water warm.
Continuous Flow
Continuous flow units skip the tank and heat water only when you turn the tap on. That cuts waste, gives better temperature control, and means the hot water does not run out mid-shower.
They carry a 6- to 7-star energy rating and are compact enough for tight spots in a lot of Melbourne homes. They cost more upfront than a tank but use less energy day to day.
Related: Best Business Laptops for work & school
Related: Best Gaming Laptops
Related: Best Portable Laptop
Solar
Solar systems use roof panels plus an electric or gas booster for cloudy days. They are the most energy-efficient option available and also the most expensive to install.
One detail is worth knowing before you commit. Putting the tank and booster at ground level instead of on the roof avoids paying to reinforce the roof and makes servicing much easier later.
Heat Pumps
A heat pump works a bit like an air conditioner. It pulls warmth out of the surrounding air using a refrigerant and uses that to heat your water.
It runs on electricity and is one of the greener options. Because it borrows heat from the air rather than making its own, where you put it matters.
What Happens During a Service
A real service is more than a quick look and an invoice. The plumber cleans the pilot and burner, clears sludge from the cylinder if there is any, and measures your water temperature and pressure.
Then come the parts checks. The anode, the pressure and temperature relief valve, the thermocouple, and the gas controller are inspected and swapped if needed, with gas pressure adjusted where required.
How Often to Get It Serviced
Every five years is the recommended interval. Leave it longer and you are gambling with the whole system, because neglected units are the ones that spring tank leaks or fail.
You can usually fold a service into a repair visit rather than booking it separately. That tends to be the cheapest way to stay on top of it.
Why a New Unit Is Not Just a Swap
Putting in a new system involves more than unhooking the old one. The plumber checks the Mega Joule rating, essentially how much gas the unit needs, then confirms your existing pipes can handle everything you run.
They also test for gas leaks before and after the job. Installation has to meet the Australian standards AS/NZS 3500 and AS/NZS 5601, and you should receive a Certificate of Compliance once it is finished.
Setting Up the New Unit
The last step is commissioning, which just means tuning the unit so it runs properly. That covers gas supply pressure, burner settings, checking the hot water works, and setting the temperature if a tempering valve is fitted.
Two things are worth asking about by name. A tempering valve controls how hot the water is when it reaches your taps, and pressure reduction valves help the system last longer and run more efficiently.
Conclusion
Hot water systems are easy to forget about until they stop. Discoloured water, strange noises, a climbing bill or showers that run out early are worth acting on while a repair is still cheaper than a replacement.
When it is time to call someone, have them look at the system properly instead of quoting over the phone.
Ask about the five-year service schedule while they are there, and make sure anything new comes with its certificate.
Frequently Asked Questions
Should I repair my hot water system or replace it?
It comes down to the age of the unit, what has gone wrong, and whether it still suits your household. Someone needs to see it in person to weigh those up, which is why phone quotes are not much use.
How often should a hot water system be serviced?
Every five years keeps it running efficiently and safely. It can often be done during a repair visit rather than as a separate booking.
Does a plumber or an electrician install a water heater?
A licensed plumber does the installation, since it involves water and gas connections. An electrician connects the power supply only where an electric unit needs it.
What is a tempering valve?
It is a valve that controls the temperature of the water arriving at your taps. Whether you need one depends on your system, so ask the plumber during the assessment.
What usually goes wrong with hot water systems?
Leaks, pilot light problems, faulty thermostats and sediment in the tank cover most callouts. Regular servicing catches several of these before they turn into a cold shower.
Last Updated on August 18, 2026 by Nick Ross
