Trade Waste by the Numbers
Figures from Australian water authorities and regulators
200
Penalty units in Victoria for discharging trade waste without an agreement or consent, plus 80 for each day it continues
1,000 L/h
Minimum oil water separator capacity for vehicle washing set by SA Water and Central Coast Council
20 m²
Largest unroofed wash-down area Water Corporation accepts in Western Australia
40 days
After which state concurrence is assumed in regional NSW if the department hasn’t refused or asked for more information
Sources: Yarra Valley Water; SA Water Vehicle Washing guideline; Central Coast Council; Water Corporation; NSW Liquid Trade Waste Management Guidelines 2021.
Key Takeaways
- Any business wastewater other than domestic sewage needs approval before it goes to sewer.
- Whoever sends the property’s sewerage bill is usually who approves trade waste.
- Assessors rate your discharge by risk, and that rating drives conditions and fees.
- Wash bays need listed, correctly sized pre-treatment, a plan to keep rain out, and backflow protection.
- Acceptance limits differ between authorities, so a pass in one city isn’t a pass everywhere.
- Approvals don’t automatically follow a sale or a new tenant.
On This Page
- What a trade waste agreement is
- Who approves trade waste in your area
- What goes into an application
- How assessors rate wash bay risk
- Pre-treatment, roofing and backflow
- Acceptance criteria and discharge limits
- Fees and charges
- Inspections, renewals and ownership changes
- Why applications stall
- Frequently asked questions
What a Trade Waste Agreement Is and Who Needs One
Trade waste is any liquid waste from a business other than domestic sewage from toilets and staff amenities. Depending on where you are, the approval might be called an agreement, a permit, a consent or a licence. The idea is the same.
You’ll need one if your property discharges wastewater from activities like these:
Wash Bays
Vehicle, truck and machinery wash-down
Workshops
Automotive repairs, servicing and parts washing
Food Businesses
Cafes, restaurants, bakeries and food preparation
Industry
Manufacturing and other industrial processes
Discharging Without Approval Is an Offence
In Victoria, section 178 of the Water Act 1989 makes it an offence to discharge trade waste to a water corporation’s sewerage system without an agreement or consent. The penalty is 200 penalty units, plus 80 penalty units for each day the offence continues. In regional New South Wales, discharging liquid trade waste without council approval is an offence under the Local Government Act 1993.
Council or Water Utility: Who Approves Trade Waste in Your Area
| State or territory | Who approves trade waste |
|---|---|
| New South Wales | Sydney Water and Hunter Water in their areas. Elsewhere, the local council under section 68 of the Local Government Act 1993, often with state concurrence |
| Victoria | The local water corporation, such as Yarra Valley Water, South East Water or a regional water corporation |
| Queensland | Urban Utilities (Brisbane, Ipswich, Lockyer Valley, Scenic Rim and Somerset), Unitywater (Moreton Bay, Sunshine Coast and Noosa), otherwise the local council |
| Western Australia | Water Corporation across most of the state |
| South Australia | SA Water |
| Tasmania | TasWater |
| ACT | Icon Water |
| Northern Territory | Power and Water Corporation |
Quick tip: if you’re unsure, check who sends the property’s sewerage bill. That’s usually who approves trade waste.
What Goes Into a Trade Waste Application
Most applications ask for the same core information, whether you apply online or on a paper form.
About the Business and Site
- Business and property details
- The property owner’s consent if you’re a tenant
- A description of the activities producing wastewater
- A site plan and plumbing plans from a licensed plumber
About the Wastewater
- Expected daily and peak flow volumes
- A list of chemicals and detergents, often with safety data sheets
- Details of your pre-treatment equipment
- How that equipment will be maintained
Missing owner consent and vague pre-treatment details are two of the most common reasons an application sits in a queue.
How Assessors Rate the Risk of a Wash Bay Discharge
Assessors classify your discharge by risk, and that classification drives everything from approval conditions to fees. In regional New South Wales, the state’s Liquid Trade Waste Management Guidelines (2021) sort discharges like this:
| Classification | Risk | Typical volume | State concurrence |
|---|---|---|---|
| A | Low | Generally up to 5 kL a day | Assumed automatically |
| B | Medium | Up to 20 kL a day | Required, unless the council holds assumed concurrence for Class B |
| C | High risk or large | Above Class A and B limits | Required for every application |
| S | Tankered human waste | Septic, dump point and pump-out waste | Required, unless the council holds assumed concurrence for Class S |
Where concurrence is needed, it is assumed if 40 days pass after the council seeks it without the department refusing or asking for more information.
What Assessors Weigh
- Public health
- Worker safety
- Sewer capacity
- Treatment plant impact
- Pre-treatment adequacy
- Chemical storage
- Stormwater ingress
A wash bay with oil, sediment and an unroofed area ticks several of those boxes, which is why it gets more scrutiny than a cafe.
Pre-Treatment Requirements for Vehicle and Machinery Wash Bays
Requirements vary, but the pattern is consistent. SA Water’s vehicle washing guideline is a good example of a full pre-treatment train where oil and grease exceed 100 mg/L:
1. Silt Trap
A bucket with a 2 mm nominal mesh catches coarse solids.
2. Settling Sump
A settling and pump sump of at least 400 L lets solids drop out.
3. Non-Emulsifying Pump
Moves water to the separator without shearing oil into tiny droplets.
4. Oil Water Separator
Minimum 1,000 L/h capacity before discharge to sewer.
A pump that shears oil into tiny droplets defeats the separator, which is why authorities insist on non-emulsifying pumps. Here’s how a few authorities compare:
| Authority | Separator requirement | Not accepted as final pre-treatment | Worth knowing |
|---|---|---|---|
| SA Water | Minimum 1,000 L/h | Not stated in the guideline | 2 mm silt trap and 400 L sump required where oil and grease exceed 100 mg/L |
| Central Coast Council (NSW) | Coalescing plate unit of at least 1,000 L/h, or a larger unit sized to flow | Double and triple interceptor pits | Only non-emulsifying pumps may feed the separator |
| Water Corporation (WA) | Vertical gravity, coalescing plate or hydrocyclone separator | Single, double and triple interceptors | Only quick-breakdown detergents may be used |
| Sydney Water | Sized to your maximum hourly flow | Unlisted equipment | Publishes a list of approved pre-treatment products |
Use listed equipment, and you’ll usually avoid a lot of back and forth.
Bunding, Roofing and Keeping Rainwater Out of the Sewer
Sewers aren’t built for stormwater, so authorities set firm rules on keeping rain out of the wash bay.
| Authority | Roofing rule | Keeping surface water out |
|---|---|---|
| Water Corporation (WA) | Wash-down areas larger than 20 m² must be roofed. Unroofed areas are charged per square metre of catchment unless the discharge is metered | Bund the area or design it to exclude rain, with surrounding areas sloping away |
| SA Water | All areas draining to sewer must be roofed, with an overhang of at least 1 m for every 3 m of roof height on exposed sides | Reverse grade, perimeter hump, bund wall or similar |
| Central Coast Council (NSW) | Wash area must be roofed | Roofed, bunded and graded, with stormwater diverted away |
Backflow Prevention on the Wash Bay Water Supply
Wash bays can contaminate the drinking water supply if water flows backwards through a hose. Water Corporation classes wash bays as a high hazard backflow risk and requires a boundary containment device. Central Coast Council requires a reduced pressure zone device on the incoming supply, registered with council. Testable devices generally need periodic testing by a licensed plumber.
Acceptance Criteria and Discharge Limits
Every authority publishes its own acceptance criteria, and they’re not the same:
| Parameter | Sydney Water (2026-27) | SA Water vehicle washing guideline |
|---|---|---|
| Petroleum hydrocarbons | 10 mg/L (flammable) | Not specified separately |
| Oil and grease | Grease 110 or 200 mg/L, depending on treatment plant | Up to 100 mg/L |
| Suspended solids | 600 mg/L | Up to 500 mg/L |
| pH | 7 to 10 | 6 to 10 |
Oil and Grease Limits Compared (mg/L)
| SA Water | 100 |
| Sydney Water, primary treatment plants | 110 |
| Sydney Water, secondary or tertiary plants | 200 |
Suspended Solids Limits Compared (mg/L)
| SA Water | 500 |
| Sydney Water | 600 |
The Takeaway
A result that passes in Sydney doesn’t automatically pass in Adelaide.
WashBay HQ oil water separators are designed for discharge under 10 mg/L TPH with no visible oil sheen, which gives you headroom under most limits.
How Trade Waste Fees and Charges Are Calculated
Fees vary by authority, but usually include some mix of the following:
| Fee type | When it applies |
|---|---|
| Application fee | When you lodge a new application |
| Annual fee | Each year the approval is in place |
| Inspection or re-inspection fees | When the authority visits, or returns after a failed inspection |
| Usage charges | Based on the volume you discharge |
| Quality charges | Per kilogram of pollutant, usually for larger or industrial dischargers |
Example: Sydney Water Quality Charges, 2026-27
| Pollutant | Primary treatment plants | Secondary or tertiary plants |
|---|---|---|
| Suspended solids | $0.646 per kg | $2.101 per kg |
| Grease | $0.615 per kg | $1.796 per kg |
Non-Compliance Costs More
In New South Wales, regional councils can apply non-compliance usage charges when pre-treatment isn’t installed or maintained. Check your authority’s current prices before budgeting.
Inspections, Sampling and Servicing Records After Approval
Approval isn’t the finish line. Authorities can inspect your site, take samples and ask for records. Water Corporation, for example, requires a written maintenance contract for coalescing plate separators, vertical gravity separators and hydrocyclones, following the manufacturer’s servicing requirements.
Keep These Together in One File
- Service reports for your separator and pre-treatment equipment
- Pump-out receipts from your licensed liquid waste contractor
- Any sampling results
- Your current approval and its conditions
If an inspector visits, that file is your best defence.
Renewals, Changes of Ownership and Approval Terms
Approvals don’t follow the business automatically. Any change to the activity or wastewater usually means a fresh application.
| Situation | What usually happens |
|---|---|
| New owner or tenant, Urban Utilities area (QLD) | Approvals can’t be transferred, so the new owner or tenant must reapply |
| Regional NSW, owner holds the approval | A new occupier doesn’t need a new approval, but the owner must notify council. A new owner needs a new approval |
| Regional NSW, occupier holds the approval | A new occupier needs a new approval. A new owner doesn’t, but must consent for the discharge to continue |
| Change to activity or wastewater | Usually a fresh application |
| Approval term ends | Terms vary. Dubbo Regional Council approvals, for example, lapse five years after issue |
Diarise your renewal date.
Common Reasons Applications Stall and How to Avoid Them
| Problem | How to avoid it |
|---|---|
| No owner consent | If you’re leasing, get it signed early. Chasing a landlord can add weeks on its own |
| Unlisted or undersized pre-treatment | Use listed equipment, sized to the peak hourly flow from every pressure washer and hose that can run at once |
| No plan for rainwater | Show on the site plan exactly where rainwater goes |
| Missing backflow details | Include the device type and where it’s installed |
| Chemical list doesn’t match the site | Check every product on site against your list and safety data sheets |
Call Before You Lodge
Most trade waste officers are happy to tell you what they’ll want to see.
Answer Every Point at Once
If your authority asks for more information, answer every point in one response. Partial replies usually just mean another round of questions.
Getting Your Wash Bay Ready for the Assessor
1. Discovery Call
We go through your site, your wastewater, and what your council or water utility has asked for.
2. Proposal
Within 24 hours, you’ll get a quote for the bay and pre-treatment your authority expects.
3. Design & Approval
We hand over drawings, specifications and Form 15 certificates to attach to your application.
Who Prepares the Paperwork?
It’s the question that holds up more applications than any other. With WashBay HQ, the answer is mostly us.
- Engineering documentation and drawings
- Form 15 compliance certificates
- Help putting the trade waste application together
- Above-ground modular wash bays and oil water separators made in Australia
- Bunding, sediment traps and stormwater diversion options
