Water Heater Replacement Cost in Australia (2026)

If your hot water has died, the first question is usually how much a new one costs. This guide gives you indicative Australian ranges for replacing a hot water system, explains the factors that push the price up or down, and walks through the choices you will be asked to make: tank or tankless, gas or electric, repair or replace. Read it before you call anyone, so you can compare quotes on equal terms.

Typical price ranges (indicative)

As a rough guide in Australia: an electric storage tank replacement runs about $900–$2,200 installed; gas storage $1,200–$2,600; and a continuous-flow (tankless) system $1,500–$4,000, depending on capacity and fuel type. Heat-pump units sit higher. These are general indications to set your expectations - the final number depends on your home, not the sticker price. A straight swap of a failed tank in the same position, on the same fuel, reusing the same fittings, sits at the bottom of those ranges. The same job in a two-storey home, with a unit that has to come off a roof, or with a supply line that has to be upgraded, sits at the top. The gap between the cheapest and the dearest quote for what sounds like the same job is rarely the unit itself. It is the scope of work around it, which is why two plumbers can look at the same dead heater and give you figures that are a long way apart.

What drives the price

Four factors move the total most: the unit size and capacity, the fuel type (electric, gas or heat-pump), whether pipework or venting must be changed, and your local labour rate. A like-for-like swap is the cheapest way to do the job. Relocating the unit, upgrading the supply line, or adding an expansion valve adds real cost, and those items are what turn a straightforward replacement into a bigger job. Size is the first thing to understand, because you are buying storage capacity or flow rate rather than just a box. A household with two bathrooms and long showers needs more than a one-bathroom unit, and larger units cost more to buy and can need a larger circuit or gas line to run them. Fuel type changes the installation itself. An electric tank is usually the simplest swap, because the wiring and the position already exist. A gas unit needs a licensed gas fitter, adequate gas pressure and a flue. A heat pump needs space to draw and discharge air, and somewhere for condensate to go. Venting and existing pipework catch people out in older homes. If the old unit vented through a wall and the new one must vent through the roof, you are paying for roof work on top of plumbing. If the cold inlet or the relief line does not meet current requirements, it will be replaced while the plumber is already there.

Tank vs tankless

Tank units are cheaper to buy and simple to replace, but they store hot water constantly, which is a higher running cost. Tankless units are pricier up front, last longer and save space, but they need adequate gas or electric capacity and can cost more to install because of the flue, the gas line sizing or the electrical supply. Neither option is automatically the better one. Match the choice to your household size and your energy plan, not just the purchase price. A large family that uses hot water in two places at once needs a continuous-flow unit sized to run both together, and that lifts both the unit price and the installation cost. A smaller household that cares mainly about the up-front figure may be better served by a tank. Ask for both to be priced for your address. The installation difference is specific to your home - your gas meter, your switchboard, your roof - and no online calculator can see any of it. If you are comparing on running cost instead of purchase price, check the unit's energy rating label against your own tariff, and ask what the unit actually draws.

Heat pumps and other options

Heat-pump units sit higher again on purchase price. They move heat out of the air rather than generating it, much like a reverse refrigerator, so they use far less electricity to produce the same hot water. They need clear space around them for air movement, a path for condensate, and usually a power supply that can handle the start-up load. In a Sydney climate they work well, and a north-facing wall or a sheltered outdoor corner suits them better than a cramped internal cupboard. Solar hot water is the other option worth asking about. A system with roof collectors and a storage tank can cut running costs sharply on a sunny roof, but it needs roof space, a suitable mounting point and usually an electric booster for cloudy weeks. If you are replacing an old electric tank, ask what the running cost difference looks like against your own usage. The right answer depends on how many people live in the house and how much hot water they actually use, not on a generic comparison.

What a replacement actually involves

A replacement is more than unbolting one unit and bolting in another. The plumber drains and disconnects the old system, isolates the power or gas, then removes the unit, which is heavier and more awkward than it looks, especially off a roof or out of a tight laundry cupboard. Then comes the part that decides the price. The new unit has to sit on a sound base, with the pressure and temperature relief valve piped to a safe discharge point. The cold inlet needs the right fittings and usually a tempering valve so the water at the tap is at a safe temperature. The flue has to be run and clearances checked. The electrical connection has to be made, and a heat pump may need a dedicated circuit. Finally the system is filled, purged of air, checked for leaks and run up to temperature. You should be shown the isolation valves and told what to do if water appears. If the old unit failed because of something else, such as a dripping relief valve or high pressure, ask whether that has been addressed, because replacing the heater without fixing the cause is how you end up doing it twice.

Sizing the system to your household

Two questions decide most of the specification: how many people live in the house, and how many hot water outlets get used at the same time. Storage units are sized in litres. Continuous-flow units are sized by flow rate and the temperature rise they have to achieve. A one or two person household with a single bathroom needs far less capacity than a family of five with two bathrooms and a dishwasher. If you run the shower while the washing machine fills, you are asking for hot water in two places at once, and that is a sizing decision rather than a luxury. Your existing fuel is the second question. Replacing an electric tank with another electric tank is usually the cheapest path, because the wiring, the position and the plumbing are already in place. Moving to gas means a gas line to the unit, a flue and a licensed gas fitter. Moving to a heat pump means space and airflow, and possibly a new circuit. Tell the plumber the unit's location, your household size, and whether you prefer gas or electric - that lets them quote the job including any pipework, rather than a ballpark.

Licensed work and compliance

Replacing a hot water system is licensed work. In New South Wales the water side must be done by a licensed plumber, and a gas installation also requires a licensed gas fitter. A reputable installer holds both or works alongside someone who does, so you should never be asked to accept an unlicensed handyman for this job. Ask for the licence number before work starts and check that it is current. A compliant installation includes the safety valves and discharge pipework described above, correct flue clearances, and, where it is required, a certificate of compliance for the work. Keep that certificate with the quote and the receipt. If your home is under strata management, the owners corporation may have rules about common property, roof access, noise hours and where a unit may sit. Sort that out before the plumber arrives, not on the day. Ask whether the installer carries public liability insurance and get the answer in writing. It matters the moment a unit is dropped, a roof tile cracks, or a pipe repair goes wrong.

Running costs, warranty and servicing

The purchase price is only part of what you pay. A storage tank keeps water hot all day, losing heat through its walls and reheating it. A continuous-flow unit heats only what you draw but can struggle to serve several outlets at once. A heat pump is the most efficient of the three on electricity, and solar with a booster can be cheaper again on a good roof. Ask what the manufacturer's warranty covers and for how long. The tank or heat exchanger, the parts and the labour are often covered for different periods, and labour is frequently excluded. Ask what you have to do to keep the warranty valid. Most tanks want the relief valve checked and some models need an anode replaced, and skipping that servicing is a common reason a claim is refused. Storage tanks typically last 8–12 years, and continuous-flow units often 15–20 with maintenance. Age and leaks are the usual reasons to replace, and once a tank is leaking from the shell, no amount of repair will save it.

What a written quote should contain

Always get a written quote before work starts, and read it before you accept. It should show the business name, licence number and ABN, the make and model of the unit being supplied, its capacity and fuel type, what is included in the installation, what is excluded, the total price, and whether GST is included. If the quote does not name the unit, you cannot compare it with another. The only way to know the real number is on-site. Tell the plumber the unit's location, your household size, and whether you prefer gas or electric - that lets them quote the job including any pipework, rather than a ballpark. A rough range over the phone is normal. A firm price from someone who has not seen the job often grows later. Check whether removal and disposal of the old unit are included, and whether the quote covers making good any wall, ceiling or roof surface opened during the work. Ask what a variation would cost if the job turns out to be bigger than expected, and get any change agreed in writing before it is done.

Sydney-specific factors

Sydney homes vary enormously, and that shows up in the quote. Many were built before the 1980s with galvanised pipe, which corrodes from the inside and may need a section replaced while the heater is out. A pipe repair inside an older wall can mean opening plaster and making good, and that is a labour cost rather than a parts cost. Where the unit sits matters too. A roof-mounted or roof-adjacent tank needs safe access, and if the venting has to move from the wall to the roof you are paying for roof work as well as plumbing. A laundry or internal cupboard leaves little room to work and may need the doorway protected. In exposed coastal suburbs, some units and fittings corrode faster, so ask about the right materials for your area. Strata and apartments add another layer. Roof access, common property and a shared hot water plant all change who you have to ask and when. If your building runs a shared system, replacing your own unit is usually not the answer. A heat pump needs outdoor air and space, and a continuous-flow unit needs gas capacity and a flue, so if your situation rules one out, the plumber should say so rather than force a fit.

Repair or replace, and how to decide

Small repairs are cheap. A thermostat or a heating element is a modest fix, and a service can bring an ageing unit back to working order. A leaking tank or a corroded unit is a different matter; once the shell has failed, replacement is usually the better spend. If you are not sure where the water is coming from, a leak detection assessment is worth having, because a puddle under the heater is not always the heater. When the unit is old and the repair is more than a small part, do the arithmetic honestly. A repair that buys six months on a tank already past its working life is money you could have put toward the replacement. A repair on a younger unit with plenty of life left is usually worth doing. If you are not sure which way to go, ask for both to be priced, with the reasons. A good plumber will tell you when repairing is the sensible call, even though replacing pays them more. And if what you actually have is a blocked drain, a dripping tap or a toilet repair, say so when you call, because it changes the job and the price. A Sydney plumber who can put a written quote for both options in front of you, with the licence number on it, is the one to keep.