waterdamagequotesHot water system leaking or burst: what happens next
A hot water failure is a burst pipe with two differences. The volume arrives all at once, and the failure was predictable — which is an engineering detail and an insurance problem respectively.
A hot water system failure is a burst pipe with two differences: the volume arrives all at once, and the failure was predictable. The first is an engineering problem and the second is an insurance one.
If it is leaking now
- Close the cold water inlet valve at the top of the unit. This is the one that stops it refilling. Everything else is secondary.
- Kill the power or the gas. Electric: the dedicated circuit at the switchboard. An element energised in a draining tank will burn out and can be a fire risk. Gas: the control knob to off or pilot.
- Open a hot tap somewhere in the house to relieve pressure and let the tank drain in a controlled way rather than through the failure.
- Photograph it before it is moved. The unit, the compliance plate with the date on it, the failure point, the water line on the wall, the extent of the spread. Plumbers take failed units away, and once it is gone the evidence is gone.
Where the water goes
The tank’s rated capacity is on its compliance plate, and this site does not publish a typical figure, because none was read from a primary source. The tank contents are the beginning, not the total: once the tank has a hole in it the inlet keeps feeding it at mains pressure until someone closes the valve, so an overnight failure puts far more than a tank’s worth on the floor.
Where the unit is installed decides what gets wet, and so which of this site’s other pages the job turns into:
| Where the unit is | What the water reaches | Ask the restorer about |
|---|---|---|
| Internal laundry or cupboard | Adjoining rooms, through the wall plate and under the skirtings; along the joists in a suspended floor, so the damp patch can appear in a room that does not adjoin the laundry | Moisture readings in every adjoining room, and whether the carpet dries in place |
| Garage | Usually a graded slab and a drain; the building only if the water runs under an internal wall | The wall base on the house side of the garage |
| External wall | The wall base and the subfloor behind it, because the unit discharges against the wall it is mounted on | Subfloor readings, which are a separate line item |
| Roof space | The ceiling below, and the whole room under it at once | Whether the ceiling is safe to stand under before anything else |
The compliance plate is the document the claim turns on. Photograph it before the plumber takes the unit away. It has the manufacture date, the capacity and the model on it, and that date is the fact the wear-and-tear argument is conducted with.
If the water is coming from the relief valve rather than the tank, the relief valve guide covers the bucket test and where the drain line must go.
Why this is the hardest wear-and-tear case
Insurance Contracts Regulations 2017 (Cth) reg 19(2)(b) · 2021 compilation, read 20 September 2026
The escape of water can be the insured event while the failed component that let it out is not.
With a flexible hose, the insurer has to reason about a component with no documented service life. With a hot water unit it does not have to reason at all: manufacturers state expected service lives, warranties are written against them, and a corroded cylinder at the end of a documented life is the textbook example of the thing reg 19(2)(b) excludes.
So the expected shape of the answer is worth knowing in advance: the water damage is a listed event; the unit is the part reg 19(2)(b) takes back out. Budget for a new unit, and do not treat the decline of the unit as a decline of the claim. If the whole claim is declined, the declined-claim page sets out what the insurer has to put in writing, and the excess page covers what comes off the part that is paid.
The one place this gets interesting is a young unit that failed. A four-year-old cylinder that corroded through is not wear and tear in any ordinary sense, it is a defective product, and that is a warranty conversation with the manufacturer rather than an insurance one. Keep the unit if you can.
The drying is a separate job from the plumbing
Four digits and only restoration companies covering your postcode call you back, and only when they are taking enquiries.
The two invoices
hipages publishes Australian plumber rates of $80 to $200 per hour with call-out fees of $150 to $250, in a guide last updated 24 July 2026. A replacement unit is on top of that and this site does not publish a figure for it, because no unit price was read from a primary source.
The drying is the other invoice. A laundry plus the adjoining room, dried over the published minimum hire of 3 days, comes to $1,557 excluding GST on the rate card this site reproduces. Five days, which is more realistic where water has gone under a wall into a second room, is $2,269.
The part that gets missed
Hot water failures produce a characteristic pattern of hidden damage, because the water is hot and hot water moves differently:
- Wall bases. Plasterboard wicks upward. The visible mark is lower than the actual moisture line, which is why a restorer reads the wall with a meter rather than by eye.
- Under vinyl and laminate. Both are effectively vapour barriers. Water underneath them does not evaporate and does not show, and laminate substrate swells irreversibly.
- Subfloor cavities. In a suspended timber floor the water goes down and then sideways. This is what moisture meters and thermal imaging are for, and it is the reason a restorer’s assessment is worth more than a look around.
- Insulation in the wall. Wet bulk insulation does not dry in place and does not recover its R-value. It has to come out, which means opening the wall.
Ask for the moisture map. A restoration company that has taken readings has a document showing where the water is, and that document is what stops the scope being argued about later.
Ask for hot water damage to be quoted
Cause already selected. Only companies covering your postcode call you back, and only when they are taking enquiries.
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Here is what happens after you submit:
- Your answers go only to restoration companies covering your postcode, and only when they are taking enquiries.
- No more than three of them may contact you, using the details you gave.
- You decide who, if anyone, you use. You are committed to nothing, and this does not lodge, alter or affect an insurance claim.
We are not a restoration company and we do not attend, assess or repair anything.
Common questions
Is a leaking hot water system covered by insurance?
The escape of water is a listed event under reg 19(1)(a)(vi) of the Insurance Contracts Regulations 2017 -- a hot water unit is fixed apparatus holding liquid. The unit itself is usually declined under reg 19(2)(b) as wear and tear, and hot water units are the hardest case for that argument because their service lives are well documented.
How much water is in a hot water system?
The rated capacity is printed on the unit's compliance plate, and it is only the start. A failed unit empties its whole contents and then keeps running at mains pressure until someone isolates it, which is why the volume on the floor bears no relation to the tank size.
How do I turn off a leaking hot water system?
Close the isolating valve on the cold water inlet at the top of the unit. For electric units also switch off the dedicated circuit at the switchboard -- an element firing in an empty tank destroys itself. For gas, turn the gas control to off or pilot.
Why is my hot water system leaking from the bottom?
Water at the base can come from the relief valve's drain line, a fitting or union, or the tank itself. Find where it starts before deciding. YourHome's test for the relief valve is that if a bucket placed under it fills in a day, the valve needs replacement; a leak from the tank body is a matter for a licensed plumber and, if the unit is young enough, the manufacturer's warranty.
Is water dripping from the relief valve a fault?
Not necessarily. The Australian Government's YourHome guidance is that the relief valve protects the tank by relieving excess pressure, and that if a bucket placed under it fills in a day it needs replacement. Either way the discharge should go to a drain line, not onto the floor; the relief valve guide on this site covers it.
Should I replace or repair an old unit?
A question for your plumber, not for a website. What is relevant here is that the insurance answer does not change with it: the water damage is a listed event either way, and the unit is wear and tear either way.
Sources cited on this page
- Insurance Contracts Regulations 2017 (Cth)
- Insurance Contracts Regulations 2017 (Cth) reg 19(1)(a)(vi)
- Insurance Contracts Regulations 2017 (Cth) reg 19(2)(b)
- hipages, plumber cost guide (last updated 24 July 2026)
- QLD Flood Restoration, published equipment hire and extraction rates
Every figure above was read from the source it is attributed to on 20 September 2026. How we check this.