Last updated: August 2026
What is liquid waste?
Liquid waste is any waste that's mostly liquid rather than solid: wastewater from sinks and drains, used oil, leftover paint and chemicals, and trade waste from businesses like grease trap waste or septic waste. Some of it may be hazardous and need a licence. Disposed of incorrectly, it can also cause real environmental harm.
What NSW regulates
Hazardous and liquid waste in NSW carries additional regulation on top of the general rules that apply to waste. Depending on the waste, those who generate, store, treat, transport or dispose of it may need a licence. Some chemicals may also sit under a Chemical Control Order under the Protection of the Environment Operations Act 1997, restricting how they're handled through their whole life cycle. Many hazardous and liquid wastes need to be tracked through transport to their final destination. A liquid waste levy applies to certain liquid wastes that are required to be tracked, creating a financial incentive for companies to reduce how much potentially dangerous liquid waste they generate.
How NSW law defines liquid waste
NSW defines liquid waste by how it behaves, not just what it's made of: waste with an angle of repose of less than 5 degrees, waste that becomes free-flowing at or below 60 degrees Celsius or once it's being transported, and waste that generally can't be picked up with a spade or shovel.
How liquid waste gets tracked, and where it can legally end up
Some liquid waste also counts as "trackable" waste under a separate NSW schedule. Facilities that transport or receive hazardous liquid waste have to record its movement using the EPA's online waste tracking system. A liquid waste levy applies wherever the waste is liquid, trackable, and received at a scheduled waste facility anywhere in NSW, imposed to reduce liquid waste and encourage its recovery rather than disposal. Records have to be kept for at least 6 years, the levy is paid quarterly, and the EPA can issue penalty infringement notices, or refer for prosecution, where records aren't kept properly or a claim turns out to be false.
Even hazardous waste generally can't go straight to landfill. Where recycling isn't an option, an immobilisation approval from the EPA may allow it to go to landfill anyway, but only for waste that's inherently stable, either naturally or after treatment. Waste that's also classified as a "dangerous good" under Commonwealth law comes with its own separate set of requirements on top of the NSW waste rules.
Common household liquid waste, and where it goes
Most of what people search "liquid waste disposal" for is one of a handful of things:
- Used motor oil or engine fluids: has its own disposal rules. See our guide on disposing of motor oil.
- Leftover paint and paint tins: dried paint and empty tins have their own rules. See disposing of paint tins.
- Household chemicals: cleaning products, pesticides, pool chemicals. The NSW Government runs a free household chemical CleanOut program across NSW for exactly this. See household chemical CleanOut in Sydney.
- General hazardous household waste: batteries, gas bottles, and the rest of the hazardous-waste list. See our full hazardous waste disposal guide.
- Trade or bulk liquid waste (grease trap waste, septic waste, contaminated industrial wastewater) may need a licensed operator rather than a general rubbish removalist: licensing may be required for those generating, storing, treating, transporting or disposing of this kind of waste. Many hazardous and liquid wastes like this also need to be tracked through transport to their final destination.
What happens to household chemicals after a CleanOut
There are limits on what you can bring: up to 20 litres or 20 kilograms of a single item, except paint, where up to 100 litres in 20-litre containers is accepted at certain events.
Dropping something off isn't the end of the story: many chemicals are recycled, while others are treated for safe disposal. Leftover paint gets mixed with other solvents and used in cement manufacturing, and the metal tins are recycled. Gas cylinders have any remaining gas removed and the steel recycled, and many bottles go back to the hire market rather than being scrapped. Batteries have their lead, acid and plastic recovered and recycled. Fluoro tubes are crushed to separate the phosphor powder from the glass, the powder is processed to capture the mercury, and the leftover glass and metal go back into the recycling system.
How trade and business liquid waste gets disposed of
Businesses that produce trade wastewater, like restaurants and takeaway food outlets or service stations and mechanical workshops, need formal approval from Sydney Water before they can discharge it into the sewer, unless their process is one of the low-risk "deemed" processes that don't need it. Most trade wastewater customers have to install and maintain grease traps or other pre-treatment equipment before that wastewater is allowed into the system. Retail food businesses typically need in-sink and in-floor bucket traps plus a correctly sized grease trap, installed by a licensed plumber, with a Wastesafe transporter needed to come and empty, clean and maintain it regularly. Mechanical workshops, panel beaters and similar automotive trades need an oil water separation system with a collection pit and pump instead. Some substances can't be discharged into the sewer at all, and some pre-treatment equipment isn't allowed to be connected: adding solvents, bacteria, odour control agents or pesticides to a grease trap is one of the things that's not permitted. Businesses also can't connect sink-to-sewer waste disposal units, in-sink food waste disposal units or garbage grinders on their premises. It matters: the greasy waste retail food businesses produce can turn solid and block the system, and the wastewater can overflow into the environment or back into the premises itself. Discharging without approval can mean the trade waste service gets disconnected, or the water service itself gets disconnected or restricted. Sydney Water can also inspect a site to check it's in line with the permit, including taking samples of the trade wastewater at any time, on any day.
Septic tanks and on-site sewage systems
Not every property is connected to sewer. Where it isn't, the property needs its own on-site sewage management system, such as a septic tank, to treat and process the household's wastewater. Some of these systems disperse the effluent on-site; others need the waste collected and disposed of elsewhere. Installing, operating and managing one of these systems is regulated under the Local Government Act 1993 and the Local Government (General) Regulation 2021. Installing a system needs council approval in the first place, and on top of that, the landowner needs an "approval to operate" renewed with council every 5 years. Where a septic tank directs to a storage tank, it needs to be pumped out regularly by a commercial contractor under an annual contract. In the Sydney drinking water catchment, there are more than 21,000 of these on-site systems in use.
Do you need Paul's, or a liquid waste specialist?
Paul's Rubbish Removal handles general household rubbish across Sydney: furniture, appliances, e-waste, garden waste and more. We're not a licensed liquid or hazardous waste operator, so for genuine liquid, chemical, trade or septic waste, use a licensed liquid waste contractor, your council, Sydney Water or the EPA channels above.
If what you're actually dealing with is everyday household rubbish alongside that liquid waste, that's exactly what we do: see our full range of services or call 0407 125 125 for a free quote.
FAQ
What is liquid waste? Waste that's mostly liquid rather than solid: wastewater, used oil, leftover chemicals and paint, and trade waste like grease trap or septic waste.
Is liquid waste hazardous? Some is, some isn't: it depends on the specific waste rather than being a blanket rule. Where it is, NSW regulates it: licensing may be required for those generating, storing, transporting or disposing of it, and it may need to be tracked through transport to its final destination.
Can I put liquid waste in my council bin? Oil, paint, chemicals and anything classified as hazardous cannot go in your household bin: see the item-specific guides linked above, or the NSW Government's free household chemical CleanOut program.
How is liquid waste disposed of? It depends on the specific waste and who's licensed to handle it. NSW regulates who can generate, store, transport and dispose of it, and some of it needs to be tracked through to its final destination.
Do I need council or Sydney Water approval to get rid of liquid waste from my business? Usually, yes. Businesses that produce trade wastewater generally need formal approval from Sydney Water before discharging it into the sewer, and most need pre-treatment equipment like a grease trap or, for motor trades, an oil water separator installed first.
Do I need a permit for a septic system? Yes. Installing an on-site sewage system needs council approval, and once it's in, the landowner needs an "approval to operate" renewed with council every 5 years.
What happens to liquid waste that's classified as "trackable"? Facilities handling it have to record its movement through the EPA's online waste tracking system and keep those records for at least 6 years, and a liquid waste levy applies where it's received at a scheduled facility.
