Repaired where a repair is honest and replaced where it is not, with the trade-off nobody mentions raised before the order rather than during the next outage.
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Storage and continuous flow get compared on capacity, running cost and how long they last. There is a fourth difference that almost never comes up until it does, and out here it is worth a minute.
A storage system holds a volume of hot water. If the power goes out, that water is still hot. You have whatever was in the tank, and the only thing you lose is the ability to reheat until the supply comes back.
A continuous flow unit heats on demand and holds nothing at all, and its electronics and ignition generally need mains power to work. That surprises people about gas units in particular: the gas is doing the heating, but without electricity the thing will not start. No power means no hot water, immediately.
None of that makes continuous flow a poor choice. It cannot run out, it typically lasts considerably longer, and it holds nothing hot between uses. It is simply a real trade-off, and it deserves thirty seconds before an order goes in rather than a discovery during the next outage.
Shut it off and call. Flooring and cabinetry cost considerably more than the cylinder does.
An outage does not empty a tank. It stops it reheating, which is a different thing. You keep whatever volume was in the cylinder when the power went, minus what the standing losses take over the next day.
In practice that is a shower or two for most households, and it is the reason nobody with a storage unit notices a short interruption at all.
If the power is out for a day or more, the useful trick is to stop drawing hot water for anything that does not need it. The tank is insulated and it holds temperature surprisingly well, so what you do not use is still there tomorrow.
It heats on demand, which is its whole advantage and its whole exposure. There is no stored volume, so there is nothing in reserve when the electronics lose power.
That is not an argument against them. It is an argument for knowing which you have before the night you find out.
A few units can be run from a small battery or generator through their standard plug, which is worth asking about at the time of installation rather than in the middle of an outage. Most cannot, and the honest answer for most households is that a storage tank suits a street like this better.
This is the part that surprises people. The ignition and control board on a modern gas unit run on mains power even though the gas is doing the heating, so a gas unit without power will not fire.
An older gas storage tank with a standing pilot is the exception, and there are still a few of those around here. If yours has a pilot you can see, it will keep going.
Worth checking which you have while nothing is wrong. It takes one look at the unit for a visible pilot flame, and it settles what happens the next time the street goes dark.
Overhead lines under a heavy canopy come down in the same weather that fills your gutters, and the streets with the best trees are the streets that lose power longest. The two problems on this site share a cause.
Nothing about that is yours to fix, and it is not ours either. It is worth factoring into the choice of system, which is the only part of it you control.
If you are replacing a unit anyway, this is the point at which the choice is genuinely open. Once it is installed you have made the decision for the next ten or fifteen years, and nobody thinks about outages while a plumber is standing in the driveway.
Sydney water is soft, so cylinders here do not silt up the way they do in hard-water cities. What kills them is corrosion, and the sacrificial anode exists to corrode instead of the steel.
Once the anode is gone the tank starts spending itself. Renewing one is a fraction of a replacement and buys years, and on a unit around the six or seven year mark it is the single best thing you can spend money on.
Nobody checks an anode on their own initiative because there is nothing to see from outside the tank. It is worth adding to a visit that is already happening, particularly on a unit whose age you do not know.
Houses out here have been extended, and the bathroom added in 1985 is frequently a long way from a unit installed where the original one went. The water sitting in that run has to be pushed out before hot arrives.
That is pipe length, not a failing heater, and no amount of work on the unit will change it. If it genuinely bothers you the answer is a recirculation line or a small unit at that end, and both are honest options rather than repairs.
There is one thing worth ruling out first. If the wait has got noticeably longer than it used to be, that is a change rather than geometry, and a change is worth a look.
A weeping fitting on top of a cylinder is a repair. Water coming from the body of the tank is not. The steel has gone and there is no patch for that which anybody should sell you.
Shut the water off at the unit, turn off its power or gas, and arrange the swap before the floor and the wall behind it join the bill. A tank that has started weeping does not get better and it does not wait politely.
If it happens in a roof space, get the water off and then get somebody up there the same day. A slow weep above a ceiling does more damage in a week than the replacement costs, and it will not announce itself until the plaster gives.
Capacity and running cost get compared everywhere. This table adds the column that normally gets left out.
| Type | How it heats | Expected span | In a power outage |
|---|---|---|---|
| Electric storage | A submerged element warms a stored volume | About 8 to 12 years | Holds what is already hot, will not reheat |
| Gas storage | A burner beneath keeps the volume hot | About 8 to 12 years | Holds what is already hot; reheating depends on the model |
| Continuous flow | Heated in transit, nothing stored | About 15 to 20 years | Generally will not run at all without mains power |
| Heat pump | Ambient warmth moved into the tank | About 10 to 15 years | Holds what is already hot, compressor needs power |
| Solar with boost | Roof collectors, with a boost for poor weather | About 15 to 20 years | Holds what is already hot; an electric boost needs power |
An opening position rather than a rule. Storage is judged on what can be drawn before the tank empties, so count the people wanting hot water in the same hour.
| Occupants | Electric storage | Gas storage | Continuous flow |
|---|---|---|---|
| One or two | 125 to 160 L | 90 to 135 L | 16 L/min |
| Three to four | 250 to 315 L | 135 to 170 L | 20 L/min |
| Five or more | 315 to 400 L | 170 L or twin | 26 L/min |
| Two bathrooms at once | Size up a step | Size up a step | 26 L/min |
Fixed price agreed before anything starts. These are indicative 2026 ranges.
Comes straight off the repair bill if you tell us to go ahead.
Two parts account for the overwhelming majority of electric failures, and both cost a fraction of a new system.
Buys years on a tank that is otherwise sound.
One number covering the appliance, fitting it, and removing the old one.
Only where the property has gas and a wall position that satisfies the clearances.
Hot water accounts for more callouts than anything else. Electric storage runs a good deal of the housing here, gas appears where a property is connected for it, and continuous flow shows up where a cylinder had to come off the floor. These are the makes.
We service and replace these systems as an independent licensed plumber. We are not an agent for, or endorsed by, any of these manufacturers.
Type, age and where it sits, which between them settle most of the repair or replace question before anybody drives out.
Every unit carries a compliance plate with a date, and we read it out, because a real age turns repair or replace into arithmetic.
Anode, element or thermostat where that solves it, and a changeover only where the unit is genuinely finished.
We run it, check the delivered temperature, take the old unit away and leave you the paperwork.
A licensed plumber answers directly. Repairs are usually same-day and plenty of changeovers are too.
Call 1300 381 569It depends entirely on the type, and it is the question nobody asks before changing systems. A storage tank already holds a volume of hot water, so an outage does not empty it: you have whatever was in it, and it simply will not reheat until the power returns. A continuous flow unit heats on demand and generally needs mains power for its electronics and ignition, so when the power stops so does the hot water.
Yes, in most cases, and it surprises people. The gas is doing the heating, but the electronics that control and ignite it need electricity. A gas unit without power is a gas unit that will not start.
No, and we are not arguing that. It has real advantages: it cannot run out, it lasts longer, and it holds nothing hot between uses. The point is simply that the trade-off exists and almost nobody is told about it before they order.
A heat pump needs power to run its compressor, though like any storage system it holds whatever is already in the tank. Solar with an electric boost has the same characteristic: the stored volume is there, the boost is not.
Soft water is why they fail this particular way. In hard-water places a tank silts up with scale. Sydney's is not like that, so the sacrificial anode is consumed protecting the steel and the tank starts corroding once it is gone, or an element burns out. Both are frequently repairs.
Replace. Water from the body of the cylinder means the steel has gone and there is no patch for that. Shut it off and ring, because the damage compounds daily.
Diagnosis is $120 to $250 and comes off the repair. An element or thermostat is $250 to $550. An anode is $300 to $600. A storage replacement is $1,400 to $2,800, and a continuous flow changeover $2,000 to $3,800.
Tell us the type and roughly the age. And if you are thinking about changing systems, say so, because there is a comparison worth having first.
Kept if it can be kept, replaced if it cannot, with the trade-offs said out loud.
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