No Hot Water? What to Check Before Replacing Your Hot Water System

If you suddenly have no hot water, the first step is to work out whether it is a simple supply issue, a safety concern, or a sign that the hot water system may need replacement.

Some problems are minor, such as a tripped switch or closed gas valve. Others may point to a failed element, faulty thermostat, gas issue, leaking tank, ageing cylinder or system that is no longer worth repairing. For homeowners, landlords and property managers, the key is knowing what you can safely check yourself and when to stop and call a licensed professional.

If your system is old, leaking, unreliable or repeatedly losing hot water, replacing it may be more practical than ongoing repairs. Installed Today makes it easy to compare replacement hot water systems, including electric hot water systems, instant gas hot water systems and heat pump hot water systems.

Quick answer: why is there no hot water?

No hot water is usually caused by one of these issues:

• Power supply issue on an electric hot water system

• Tripped circuit breaker or blown fuse

• Failed heating element

• Faulty thermostat

• Gas supply issue on a gas hot water system

• Pilot light or ignition fault

• LPG bottle issue

• Faulty gas component

• Leaking hot water tank

• Tempering valve or mixing issue

• Sediment build-up

• Undersized system

• End-of-life hot water unit

If there is water leaking from the tank, a burning smell, electrical issue, gas smell, scorch marks, or the system keeps tripping power, stop using it and contact the appropriate licensed trade.

First: is it no hot water or not enough hot water?

Before assuming the system has failed, work out what is actually happening.

No hot water at all

This usually means the system is not heating. It may relate to power, gas, ignition, thermostat, heating element, controller, wiring or a failed component.

Hot water runs out quickly

This may mean the system is undersized, one heating element has failed, the thermostat is not working correctly, the tank has sediment build-up, or the household is using more hot water than the system was designed for.

Hot water is warm but not hot

This may point to thermostat settings, tempering valve issues, a failed element, gas burner problems, solar boost issues, or a system that is struggling to recover.

Hot water is only missing from one tap

If only one shower, mixer or tap has an issue, the problem may be local to that fixture rather than the whole hot water system.

This first step helps you decide whether the issue is likely system-wide or limited to one outlet.

Safety warning before checking anything

Hot water systems involve electricity, gas, pressure, high temperature water and plumbing. Do not remove panels, touch wiring, adjust gas components, bypass valves, open sealed parts or attempt internal repairs yourself.

Only complete basic visual and supply checks. Anything involving electrical testing, gas work, internal components, valves, thermostats, heating elements, burners or pipework should be handled by a licensed professional.

If you smell gas, leave the area, avoid using electrical switches or flames, and contact your gas supplier or emergency service provider.

Basic checks for electric hot water systems

Electric hot water systems are common in Australian homes. If your electric hot water system has stopped working, start with safe external checks only.

Check the switchboard

Look for a tripped circuit breaker or safety switch. If the hot water circuit has tripped, it may explain why the system is not heating.

If you reset it once and it stays on, the system may begin heating again. If it trips again, do not keep resetting it. Repeated tripping can indicate a fault that needs a licensed electrician or hot water professional.

Check whether the system has power

Some electric hot water systems have an isolating switch near the unit. Make sure it has not been accidentally turned off.

Do not open the electrical cover or test wiring yourself.

Consider off-peak or controlled load timing

Some electric storage hot water systems only heat during certain tariff periods. If hot water was heavily used earlier, it may need time to reheat.

If the system is on a controlled load or timer, it may not recover immediately during the day. A licensed electrician can confirm the setup if you are unsure.

Look for leaks around the tank

Check around the base of the cylinder, valves and pipework. A small amount of discharge from a relief valve can be normal in some situations, but pooling water, constant leaking or water from the tank body is not normal.

A leaking tank often means replacement is needed.

Common electric hot water problems

Electric hot water systems can fail for several reasons.

Failed heating element

An electric storage system usually relies on one or more heating elements. If an element fails, the system may produce no hot water or only a limited amount of hot water.

Signs may include:

• No hot water

• Long recovery time

• Hot water running out much sooner than normal

• Circuit breaker tripping

• Inconsistent heating

A failed element needs licensed diagnosis and replacement. If the system is old, it may be worth comparing repair cost against replacement.

Faulty thermostat

The thermostat controls water temperature. If it fails, the system may not heat correctly.

Possible signs include:

• Water is lukewarm

• Water is too hot

• Temperature changes unexpectedly

• System does not recover properly

Thermostat work should be completed by a qualified professional.

Tripped circuit or electrical fault

If the hot water circuit keeps tripping, there may be an electrical fault, water ingress, failed element, damaged wiring or another unsafe issue.

Do not repeatedly reset the breaker. Have the system checked.

Sediment inside the tank

Over time, some storage tanks can collect sediment. This can affect heating performance, reduce efficiency and contribute to noise or slower recovery.

If the system is older and performing poorly, replacement may be more practical than trying to extend its life.

Basic checks for gas hot water systems

Gas hot water systems may be storage or continuous flow. If your gas hot water has stopped working, start with safe external checks only.

Check whether other gas appliances work

If your cooktop or other gas appliance is also not working, the issue may be with the gas supply rather than the hot water system.

Check the gas valve position

A gas valve may have been accidentally turned off. Do not force valves or adjust components you are unsure about.

Check LPG bottles if applicable

If your home uses LPG, one or both bottles may be empty or turned off. Also check whether the changeover valve has switched properly.

LPG bottle management matters, especially for rental properties, granny flats and short-stay accommodation.

Check the controller if fitted

Some continuous flow gas systems have wall controllers. Look for error codes, blank screens or unusual display messages. The manufacturer manual may explain the code, but repair should still be handled by a licensed professional.

Do not relight or repair if you smell gas

If you smell gas, do not try to relight the system or keep troubleshooting. Leave the area and contact your gas supplier or emergency service provider.

Common gas hot water problems

Gas hot water systems can stop working for several reasons.

Ignition or pilot issue

Older gas systems may have pilot lights. Newer continuous flow systems usually use electronic ignition. If the system cannot ignite safely, it will not heat water.

Possible signs include:

• No hot water

• Error code on controller

• Clicking but no ignition

• Pilot light will not stay lit

• System starts then cuts out

Gas ignition issues should be handled by a licensed gas fitter.

Gas supply problem

The system may not be receiving enough gas due to:

• Closed gas valve

• Empty LPG bottle

• Gas meter issue

• Regulator problem

• Undersized gas pipework

• Gas supply interruption

• Another gas appliance affecting supply

Gas supply problems must be checked safely by qualified people.

Faulty thermocouple or flame sensing component

Older pilot-style gas systems may rely on a thermocouple. If it fails, the pilot may not stay lit and the gas supply may shut off.

This is not a DIY repair.

Blocked filters or flow issue

Continuous flow systems need enough water flow to activate. If the inlet filter is blocked or the flow is too low, the unit may not fire.

A licensed technician can check filters, flow sensors and system operation.

Common problems across all hot water systems

Some issues can affect electric, gas, solar, heat pump and storage systems.

Leaking tank

A leaking hot water tank is one of the clearest signs that replacement may be needed.

Warning signs include:

• Water pooling around the base

• Rust marks on the cylinder

• Water leaking from the tank body

• Constant discharge from valves

• Corrosion around fittings

• Dampness around the installation area

If the tank itself is leaking, repair is often not practical. Compare replacement options in the hot water systems collection.

Tempering valve issue

A tempering valve mixes hot and cold water to deliver safer outlet temperatures to bathrooms. If it fails or sticks, the water may feel too cool or inconsistent even if the hot water system is heating correctly.

This can make people think the hot water system has failed when the issue is actually with the valve.

Tempering valve work should be done by a licensed plumber.

Pressure limiting valve or water pressure issue

Poor pressure or a faulty valve can affect hot water performance. This may show as weak hot water flow, fluctuating temperatures or poor shower performance.

Before replacing a hot water system because of low pressure, have the cause checked.

Sediment or water quality problems

Sediment, scale and poor water quality can affect hot water performance over time. This can be more noticeable in older systems, hard water areas, tank water properties or homes with rust and sediment in the supply.

If water quality is a concern, you may also want to compare water filter systems as a separate upgrade.

Undersized system

Sometimes the hot water system is not broken. It is simply too small for the home.

This is common when:

• More people now live in the home

• Children have become teenagers

• A second bathroom has been added

• A granny flat has been connected

• The property has become a rental

• The home is now used as Airbnb accommodation

• Shower habits have changed

If the system runs out but then reheats normally, sizing may be the issue.

When no hot water means replacement may be better

Repair may make sense for some newer systems, but replacement may be the better option when the system is old, leaking or unreliable.

Replacement may be worth considering if:

• The tank is leaking

• The system is near or past its expected service life

• Repairs are becoming frequent

• Parts are difficult to source

• The system is badly corroded

• It keeps tripping power

• It cannot keep up with household demand

• It is undersized for the property

• You want to change from electric storage to heat pump

• You want to change from storage gas to continuous flow gas

• You are renovating or upgrading the property

If the current system has failed completely, compare like-for-like replacement first, then consider whether a different size or type would better suit the home.

Should you repair or replace your hot water system?

The repair vs replacement decision depends on age, condition, cost and suitability.

Repair may make sense when:

• The system is relatively new

• The issue is minor

• The tank is not leaking

• The system is correctly sized

• Parts are available

• A licensed professional confirms repair is worthwhile

Replacement may make sense when:

• The storage tank is leaking

• The system is very old

• Multiple components are failing

• The system has ongoing problems

• The unit is undersized

• Repair cost is high compared with replacement

• You want a more efficient or better-sized system

• The property has changed use

For supply-only buyers, confirm the issue with your licensed installer before ordering a replacement.

Choosing a replacement electric hot water system

If your old electric storage system has failed, replacing it with a similar electric storage unit is often the simplest option.

Common replacement sizes include:

• 80L for small units or low-use spaces

• 125L for small homes, units and granny flats

• 160L for 1–2 bathroom low-to-moderate use

• 250L for family homes and 2 bathroom properties

• 315L for larger families or higher use

• 400L for high-demand homes

You can compare options in the electric hot water systems collection.

Choosing a replacement gas hot water system

If your old gas system has failed, check whether it is natural gas or LPG before choosing a replacement.

Common gas replacement options include:

• Gas storage hot water

• 16 L/min continuous flow gas

• 20 L/min continuous flow gas

• 26 L/min continuous flow gas

A continuous flow gas hot water system may suit homes that already have suitable gas supply and an external installation location.

Gas systems must be installed by a licensed gas fitter. Natural gas and LPG are not interchangeable, so select the correct model.

Choosing a replacement heat pump hot water system

If your electric storage system has failed and you want a more efficient electric option, a heat pump hot water system may be worth comparing.

Heat pumps can suit homes with:

• Suitable outdoor space

• Good airflow

• Condensate drainage

• Electrical suitability

• Enough room for the unit

• Acceptable noise placement

• Long-term efficiency goals

They may not suit tight courtyards, enclosed areas, difficult drainage locations or homes needing the lowest upfront replacement cost.

What if your hot water is only lukewarm?

Lukewarm water can be caused by several issues, including:

• Thermostat fault

• Failed heating element

• Tempering valve issue

• Gas burner issue

• Solar boost issue

• Heat pump recovery issue

• Undersized system

• Heavy recent hot water use

Do not increase settings or bypass valves yourself. Have the system checked, especially if outlet temperatures are unsafe or inconsistent.

What if your hot water runs out too fast?

Hot water running out too fast may mean:

• The system is undersized

• A heating element has failed

• The thermostat is faulty

• The household has increased usage

• A shower head has a high flow rate

• The system is old and inefficient

• Sediment is affecting storage capacity

• The property has changed use

If the system has always been too small, replacing it with the same size may not solve the issue. Compare a larger size or different system type before ordering.

What if the hot water system is leaking?

If the system is leaking from the tank body, replacement is often the likely outcome.

A leak from a valve or fitting may be repairable, but it still needs professional assessment. Do not ignore leaks around electrical equipment, gas equipment or pressurised hot water cylinders.

If there is significant water leakage, isolate the water supply if safe to do so and contact a licensed plumber.

What if the hot water system keeps tripping power?

If the hot water system keeps tripping the circuit breaker, stop resetting it repeatedly.

Possible causes include:

• Failed heating element

• Water entering electrical components

• Wiring fault

• Faulty thermostat

• Damaged circuit

• Internal system fault

This needs a licensed electrician or qualified hot water professional. Continuing to reset a tripping circuit can be unsafe.

What if the gas hot water system shows an error code?

Many continuous flow gas systems display error codes on a controller. The code may relate to ignition, flame failure, water flow, overheating, fan operation or another fault.

You can check the manufacturer manual to understand what the code refers to, but repairs should be handled by a licensed gas fitter or qualified technician.

If the error keeps returning, the system may need repair or replacement.

Hot water stopped working in a rental property

For landlords and property managers, no hot water should be treated as a priority issue.

Start by confirming:

• Whether the issue affects the whole property

• Whether it is electric or gas

• Whether the switchboard has tripped

• Whether LPG bottles are empty

• Whether the tank is leaking

• Whether tenants have had repeated issues

• Age and condition of the system

For rental properties, replacement is often worth considering if the unit is old, unreliable, undersized or causing repeat callouts.

A rental property may need a more flexible size than the current tenant requires, especially if future occupants may have higher demand.

Hot water stopped working in an Airbnb or short-stay property

For Airbnb and short-stay properties, hot water issues can quickly affect guest reviews.

A short-stay property should be sized for maximum guest occupancy, not average use. If guests regularly run out of hot water, the system may be undersized even if it technically works.

Common short-stay replacement options include:

• 160L electric storage for compact stays

• 250L electric storage for family stays

• 315L or 400L electric storage for larger homes

• 20 L/min or 26 L/min continuous flow gas where suitable

• Heat pump hot water where outdoor location and recovery time suit

If the current system has failed during bookings, replacement planning should also consider access, booking gaps and guest disruption.

Supply only vs supplied and installed

Installed Today offers supply-only hot water systems across major Australian metro areas for customers who already have their own licensed installer arranged. Supplied-and-installed options are available on selected products in eligible Brisbane and Gold Coast service areas where shown.

Supply-only product pricing generally does not include installation, valves, electrical work, gas work, pipework changes, drainage changes, old unit removal, disposal or compliance upgrades unless those items are clearly selected or included.

If your system has stopped working and you are ordering supply only, confirm the correct replacement type, size, gas type and installation requirements with your licensed installer before ordering.

Hot water replacement in Brisbane and Gold Coast

For eligible Brisbane and Gold Coast service areas, Installed Today offers supplied-and-installed options on selected hot water products where available.

Common replacement options include:

• Electric storage hot water systems

• Instant gas hot water systems

• Heat pump hot water systems

• Natural gas and LPG models where available

• Selected brand options from Rheem, Rinnai, Dux and other available ranges

Before ordering, check the product page, delivery options, installation availability and any required add-ons for your property.

What to check before ordering a replacement

Before ordering a replacement hot water system, check:

• Current system type

• Current tank size or L/min rating

• Brand and model

• Indoor or outdoor location

• Number of people in the home

• Number of bathrooms

• Whether the old system ran out often

• Natural gas or LPG if gas

• Electrical requirements if electric or heat pump

• Access for delivery

• Space and dimensions

• Valve requirements

• Drainage

• Whether old unit removal is needed

• Whether you need supply only or supplied and installed

This helps avoid ordering the wrong system.

Common mistake: replacing the same size even though it always ran out

If your old system regularly ran out of hot water, replacing it with the same size may continue the problem.

Before ordering, compare whether the home now needs:

• Larger electric storage

• Higher flow instant gas

• Heat pump hot water

• Better matched system capacity

• Different setup for rental or Airbnb use

The replacement should suit current demand, not only the original system size.

Common mistake: assuming no hot water means the whole system is dead

Some no-hot-water problems are caused by electrical supply, gas supply, thermostat, valve or control issues. The system may not always need replacement.

However, if the tank is leaking, the system is old, or repairs are becoming frequent, replacement may be the more practical choice.

Common mistake: doing unsafe DIY repairs

Do not attempt DIY repairs on gas, electrical or pressurised hot water components.

Avoid:

• Removing electrical covers

• Touching wiring

• Adjusting gas parts

• Bypassing safety valves

• Plugging relief valve outlets

• Removing thermostats or elements

• Modifying pipework

• Installing gas units yourself

Use licensed trades for diagnosis, repair and installation.

Common mistake: choosing the cheapest replacement without checking fit

The cheapest replacement may not be the right system.

Check:

• Size

• Capacity

• Gas type

• Flow rate

• Dimensions

• Location

• Access

• Electrical requirements

• Required valves

• Installation availability

A system that does not fit or does not suit the home can create delays and extra costs.

Final recommendation

If you have no hot water, start with safe basic checks: power, switchboard, gas supply, LPG bottles, controller display and visible leaks. Do not open the system, touch wiring, adjust gas components or attempt internal repairs.

If the issue is minor, a licensed professional may be able to repair it. If the system is old, leaking, undersized, unreliable or no longer suitable for the home, replacement may be the better long-term choice.

For electric replacements, compare electric hot water systems. For gas-connected homes, compare instant gas hot water systems. If you want a more efficient electric option and the location suits, compare heat pump hot water systems.

To view all replacement options, browse the Installed Today hot water systems range.

Long-tail FAQs

Why do I suddenly have no hot water?

You may have no hot water because of a tripped circuit breaker, power issue, failed heating element, faulty thermostat, gas supply issue, ignition fault, empty LPG bottle, leaking tank or failed hot water system.

What should I check first if I have no hot water?

Check whether the issue affects the whole home, then safely check the switchboard, power supply, gas supply, LPG bottles if applicable, controller display and visible leaks. Do not open the unit or attempt internal repairs.

Why is my electric hot water system not heating?

An electric hot water system may stop heating because of a tripped breaker, failed element, faulty thermostat, wiring issue, timer problem or internal system fault.

Why is my gas hot water system not working?

A gas hot water system may stop working because of gas supply issues, LPG bottle problems, ignition failure, pilot light issues, blocked filters, faulty components or controller errors.

Is a leaking hot water system repairable?

A leak from a valve or fitting may be repairable, but a leak from the tank body usually means replacement is needed. A licensed plumber should assess the source of the leak.

Why does my hot water run out quickly?

Your hot water may run out quickly because the system is undersized, a heating element has failed, the thermostat is faulty, sediment has built up, or household demand has increased.

Should I repair or replace my hot water system?

Repair may suit a newer system with a minor fault. Replacement may be better if the system is old, leaking, unreliable, undersized or expensive to repair.

Can I replace my hot water system with a different type?

Yes, but changing system type may involve gas work, electrical work, pipework changes, valves, drainage and compliance upgrades. Check with a licensed installer before ordering.

What hot water system should I choose if mine has failed?

If the old system worked well, start by comparing a similar replacement. If it ran out, leaked or no longer suited the home, compare a larger size or different type such as electric storage, instant gas or heat pump.

Does Installed Today repair hot water systems?

Installed Today focuses on hot water product supply, with supplied-and-installed options available on selected products in eligible Brisbane and Gold Coast service areas where shown. For fault diagnosis or repair work, use an appropriately licensed plumber, gas fitter or electrician.