Grey water damage: washing machine, dishwasher and shower overflows

Category 2 water looks clean and is not. Health departments treat greywater as potentially infectious, and kitchen water can be dirtier than sewage.

Read from primary sources · Editor-reviewed · Current as at 20 September 2026

By the waterdamagequotesau.com editorial team · Published 20 September 2026 · Last reviewed 20 September 2026 · 8 min read

7 primary sources cited on this page. How we check what is on this site

Western Australia’s Department of Health says many people assume greywater is clean and safe because it is not sewage. A washing machine that overflows into the laundry looks like a clean-water job, and it is not: health departments treat greywater as potentially infectious, and the water from a dishwasher or kitchen sink can be dirtier than sewage. That changes what can be kept, what has to be sanitised, and how fast the job has to start.

Where grey water sits between clean water and sewage

The three categories restorers scope against, with the health departments’ descriptions of greywater. Read 28 September 2026.
	Category 1 — clean	Category 2 — grey water	Category 3 — black water
Typical source	A burst supply pipe, a tap left running	Washing machine, dishwasher, shower, bath or basin overflow	Sewage, toilet overflow with faeces, floodwater
Health departments say	—	Potentially infectious; capable of transmitting disease (NSW Health, WA Health)	Sewage; floodwater is often contaminated by it (Queensland)
Carpet and underlay	Can be dried in place if caught early	Dried, cleaned and sanitised; underlay may be replaced	Removed and disposed of
If it sits	Moves towards Category 2	Moves towards Category 3	—

The last row is the one that costs money. A category is not fixed at the moment the water arrives: grey water left in a warm carpet for days is not the same job as grey water extracted the same afternoon. Categories and classes explains the framework, and sewage backup covers Category 3.

Failed braided flexible hose under a bathroom vanity, still connected — A split supply hose is the fixed part of an appliance leak. Photograph it before the plumber takes it away.

What counts as grey water, and why kitchen water is worst

NSW Health, Greywater Reuse in Sewered Single Domestic Premises (April 2000) · April 2000, the version on the department’s site when read 28 September 2026

Greywater may come from the shower, bath, hand basin, laundry tub, washing machine, kitchen sink and dishwasher. NSW Health defines it as wastewater not grossly contaminated by faeces or urine, and says that because of its high potential to contain pathogenic micro-organisms health authorities consider it a potentially infectious and polluting liquid, and that all forms of greywater are capable of transmitting disease.

“Not grossly contaminated” is doing careful work in that definition. It does not say free of faeces or urine. Western Australia’s Department of Health is plainer:

WA Department of Health, Code of Practice for the Reuse of Greywater in Western Australia 2010, s 1.6 · 2010, read 28 September 2026

Laundry greywater. The code says bathroom greywater also contains some faecal matter from body washing, that many assume greywater is clean and safe because it does not contain blackwater, but it may contain disease-causing organisms, and that all types of greywater are capable of transmitting disease through contaminated hands, inhaled spray and broken skin.

So a washing machine that was running a load of nappies or bedding when its hose split is not a clean-water event, whatever the water looks like on the floor. And the worst grey water is not from the laundry at all:

NSW Health, Greywater Reuse in Sewered Single Domestic Premises (April 2000) s 6.2 · April 2000, read 28 September 2026

Kitchen wastewater, heavily polluted with food particles, oils and fats; the policy adds that on occasions kitchen greywater may be more contaminated with micro-organisms than raw sewage, and that dishwasher water is very alkaline from the detergent.

The Better Health Channel puts the same point in one line: Laundry rinse water is low risk, while greywater from the kitchen is high risk. (Better Health Channel (Vic), Greywater – recycling water at home). A dishwasher that has flooded a kitchen, or a blocked sink that has overflowed across a floor, carries food waste, fats and detergent into the floor coverings and the cabinet bases. Treat it more cautiously than a laundry overflow: gloves, no children or pets in the room, and nothing that touched it goes back into use without cleaning.

Get a grey water overflow dried today

Four digits, and restoration companies advertising for your postcode call you back. Tell them what overflowed.

The first hour

Stop it. Turn the appliance off at the wall and close the tap on its supply hose. For a blocked waste, stop using every fixture that drains into it.
Keep people and pets out. The health guidance for greywater reuse is to keep children and pets away from it and wash hands after contact; the same applies to a flooded laundry.
Photograph before anything moves. The hose, the connection, the tap, the water line on the cabinets and the extent on the floor. The failed hose is the evidence of what happened.
Get the water out the same day. The Better Health Channel advises not to store untreated greywater longer than 24 hours because microbes thrive; water in a carpet is stored water.

What the claim turns on

Insurance Contracts Regulations 2017 (Cth) reg 19(1)(a)(vi) · 2021 compilation, read 20 September 2026

This is the provision that puts burst pipes, split flexible hoses, failed hot water units and overflowing cisterns inside standard cover. It says nothing about how old the pipe was.

The words are fixed apparatus, fixed tanks and fixed pipes. A split supply hose or a failed tap connection sits comfortably inside them; whether a particular freestanding appliance is “fixed” is a question for the policy wording and the facts, and this site does not answer it for you. The other argument to expect is age: Insurance Contracts Regulations 2017 (Cth) reg 19(2)(b) takes wear, tear and gradual deterioration out of standard cover, which is why the photograph of the failed hose matters. The burst pipe guide covers the same provision for supply-side failures.

What drying grey water costs

On QLD Flood Restoration’s published rate card, a laundry and the room next to it dried over four days comes to $1,913 excluding GST. Add one HEPA unit, which restorers use where the water was contaminated, and it is $2,233. Sanitising and any underlay replacement are separate lines; ask for them to be itemised. The cost page shows every line.

Common questions

What is grey water damage?

Water damage from wastewater that has not come from a toilet: a washing machine, dishwasher, shower, bath or basin. NSW Health defines greywater as wastewater not grossly contaminated by faeces or urine. Restorers call it Category 2 water, between clean supply water and sewage.

Is grey water dangerous?

Health departments treat it as potentially infectious. NSW Health says all forms of greywater are capable of transmitting disease, and WA's Department of Health says laundry greywater can contain faecal matter with the associated pathogens. Keep children and pets away from it and wash your hands after contact.

Is dishwasher water worse than washing machine water?

The health guidance says so. NSW Health describes kitchen wastewater as often more pollutant than blackwater or raw sewage, and the Better Health Channel rates laundry rinse water low risk and kitchen greywater high risk.

Can carpet be dried after a washing machine overflow?

It can be, if it is caught quickly, because Category 2 water is not sewage. Carpet wet with grey water is cleaned and sanitised as well as dried, and underlay may need replacing. The longer it sits, the closer the job moves to Category 3.

Is a washing machine overflow covered by home insurance?

The standard cover event is the bursting, leaking, discharging or overflowing of fixed apparatus, fixed tanks or fixed pipes used to hold or carry liquid, under reg 19(1)(a)(vi) of the Insurance Contracts Regulations 2017. Whether a particular appliance or hose is fixed is a question for the policy wording and the facts.

How long can grey water sit before it gets worse?

The Better Health Channel advises not to store untreated greywater for longer than 24 hours because microbes thrive. That advice is written for garden reuse, but the reason applies to water sitting in a carpet too.

Sources cited on this page

Every figure above was read from the source it is attributed to on 20 September 2026. How we check this.