Does your café need a grease trap? Trade waste approval, sizing and paying for the install

If your café, restaurant, bakery or takeaway cooks or prepares food on site, you almost certainly need a grease trap and a trade waste approval from your water utility before kitchen wastewater goes down the drain. The utility decides whether you need one and how big it must be, based on your menu, your dishwashing and your volume. Coffee-only shops are sometimes treated more lightly.

It’s one of the least glamorous lines in any fit-out budget, and one of the easiest to get wrong. A trap sits under the floor or out the back, nobody looks at it, and then a new owner finds out the old one is too small, cracked, or was never approved. This guide covers who needs one, who signs off, what the work involves and how owners pay for it.

What does a grease trap actually do?

Every time you rinse a pan, run the dishwasher or wipe down the flat-top, fats, oils and grease head for the sewer. Warm, they flow. Cool, they set like candle wax inside the pipes and, eventually, in the public sewer. Utilities call that build-up a fatberg, and it’s why trade waste rules exist.

A grease trap (utilities usually call it a grease arrestor) is a tank between your kitchen drains and the sewer. Water slows down inside it, grease floats to the top, food scraps sink, and cleaner water flows out the other side. A licensed contractor pumps out what’s collected on a schedule set in your approval.

Alongside the main tank, most kitchens also need smaller “pre-treatment” bits: basket strainers in sinks, screens on floor wastes, and sometimes a separate arrangement for the dishwasher.

Who decides if your café needs one?

Not council, and not your plumber. It’s the water utility that runs the sewer at your address. In the capitals that’s Sydney Water, Urban Utilities (Brisbane, Ipswich and surrounds), the Melbourne retailers such as Yarra Valley Water and South East Water, SA Water, and Water Corporation in WA. In many regional areas the local council is also the water authority. The business.gov.au licence finder lists the right body by location, for example South East Water’s trade waste permit.

The rules differ in detail but share the same shape everywhere:

• Sydney Water says on its new businesses page that retail food businesses need its written approval before they operate, and it may inspect the site first. Its installation requirements say approval must be sought before any grease trap is installed. Discharging without approval can see your trade waste service disconnected.
• Urban Utilities says on its food service page that businesses preparing food need trade waste approval before discharging to sewer. Its trade waste officers decide case by case whether an arrestor is needed, based on what you do and how much of it.
• Yarra Valley Water is blunt: food businesses producing trade waste must install a grease trap, and you need a Trade Waste Agreement before you start trading.
• Water Corporation in WA says businesses that prepare and cook food generally need a grease arrestor, while some smaller operations may only need in-sink or floor strainers. It also asks you to report each pump-out within seven days.

What about a coffee-only café?

This is the question we hear most from owners opening a small espresso bar, and the answer depends on where you are.

South Australia is the clearest example. SA Water changed its rules from 1 December 2018 so retail coffee shops with no cooking or food preparation on site no longer have to install a grease arrestor. Its testing found arrestors didn’t treat that kind of wastewater well, partly because milk-heavy, low-volume flows sat and soured in the tank. Basic screening devices are used instead.

Elsewhere, utilities tend to assess coffee shops on what actually happens behind the counter. A takeaway espresso bar selling pre-made pastries is a very different case from a café with a sandwich press, a panini grill and a kitchen doing brunch. Once you add eggs, bacon or a fryer, expect to be treated as a food business that needs a trap.

The safe move: describe your full menu and equipment honestly on the application, including what you plan to add in year two. A trap sized for toasties won’t cope with a weekend brunch trade.

How is a grease trap sized?

The utility sets the size, usually from:

• the fixtures that drain to it (sinks, dishwashers, combi ovens, woks, floor wastes, rotisseries);
• your peak flow and daily volume of wastewater;
• the type of food, because fried, roasted and wok-heavy menus produce more grease;
• whether the trap is shared with other tenants.

Bigger is not automatically better in the eyes of the utility, but undersized is a real problem. Urban Utilities, for example, says adequately sized arrestors must be pumped out at least every 13 weeks unless your approval says otherwise, and smaller units (it gives the example of those under 550 litres of treatment capacity) may need more frequent servicing plus a dry basket strainer. A small trap can end up costing more each year in pump-outs than a properly sized one.

In shopping centres and food courts, the landlord often owns a shared arrestor. Water Corporation notes the property owner or agent is responsible for a shared unit, but each food outlet still needs its own permit.

Buying a café or taking over a lease? Check the trap first

This is the step buyers skip. A trade waste approval generally belongs to the operator, not the premises. Yarra Valley Water says its agreement must be in the business owner’s name and isn’t transferable, so a buyer applies for a new one. It also says that before buying or starting a food business, you should confirm the property has an adequately sized grease trap for what you plan to do.

So before you settle on a business or sign a lease, ask for:

1. The current trade waste approval or agreement and the conditions on it, including the approved trap size and pump-out frequency.
2. Pump-out records and receipts for the last year or two. Yarra Valley Water warns that failing to prove cleaning can lead to non-compliance fees.
3. The location and capacity of the trap, ideally with a plumber’s look at its condition. Concrete traps can crack and baffles can corrode.
4. A call to the utility describing your planned menu. If you’re turning a sandwich bar into a pizza and pasta place, the existing trap may not pass.

Then put the answer into your negotiations. If the trap needs replacing, that’s a cost to factor into the price, or something to negotiate with the landlord as part of the lease. Our retail lease checklist and our page on buying a café or restaurant cover the wider due diligence.

What does installing or upgrading a grease trap involve?

We won’t quote installed prices, because they vary enormously by site. A small under-sink unit is a different job from a large in-ground tank. What drives the cost is fairly predictable, though:

Cost driver	Why it matters
Where the trap goes	Under a slab means cutting concrete; outside may mean excavation, a loading dock or a car park.
Size and type	Below-ground tanks need civil work and access for the pump-out truck.
Drainage changes	Rerouting sink, dishwasher and floor wastes to drain to the trap, ideally by gravity.
Approvals	Utility application, plumbing inspection and compliance certificate from the licensed plumber.
Make-good and access	Landlord consent, restoring floors and finishes, after-hours work in a centre.
Closed days	Wages, rent and lost takings while the kitchen is out of action.

Two ways to keep it under control. First, get the trap into the fit-out plan from day one, not as an afterthought once the tiles are down. Second, ask your plumber to talk to the utility before quoting, so the size in the quote is the size that will be approved. Our fit-out cost estimator lets you add the trap, the plumbing and a sensible contingency to the rest of the build.

Ask your accountant how the work is treated for tax. A grease trap built into the premises may be treated differently from equipment like a dishwasher, which may qualify for the ATO’s instant asset write-off (per asset under $20,000 for businesses with aggregated turnover under $10 million). The GST on trade invoices can generally be claimed back if you’re registered.

If the trap is the one item holding up an opening or a menu change, a short enquiry with us will show what funding might look like while the plumber finalises the quote.

An example: the sandwich bar that became a pasta kitchen

Illustrative only. An owner buys a long-running sandwich bar in a suburban strip, planning to turn it into a pasta and pizza kitchen with a deck oven, a pasta cooker and a commercial dishwasher. During due diligence they find the existing trap is a small under-sink unit, approved years ago for a cold menu.

They call the water utility, describe the new menu and learn that a larger in-ground arrestor will be needed. The plumber’s quote involves cutting the slab, rerouting the dishwasher and installing the tank out the back. The owner negotiates part of the cost off the purchase price, schedules the plumbing during the refit so the kitchen is only closed once, and finances the whole refurbishment, trap included, with a cash-flow loan sized on the existing business’s turnover. The new approval is in place before the first plate of cacio e pepe goes out.

How do owners pay for a grease trap?

It depends on the size of the job and what else is happening at the same time.

• A small unit or strainer upgrade usually comes from cash flow.
• A trap as part of a new fit-out belongs in the fit-out budget. See restaurant fit-out finance for how bigger builds are usually funded.
• A retrofit in a trading venue, especially one that means closed days, sits closer to a refurbishment. Our page on venue refurbishment loans goes into this.
• A required upgrade when you buy a business can be rolled into acquisition funding, alongside the purchase price, stock and working capital.

For trading businesses, unsecured and cash-flow options typically run from $5,000 to $500,000, sized on turnover and bank statements. Owners with property can look at secured loans from $20,000 to $5,000,000. Bad credit or an ATO debt is considered case by case. If you’re still at the planning stage, our guide to how to open a café sets out the full opening budget the trap fits into.

Sort the drain, then get back to the menu

Allora: the grease trap is the part of a kitchen nobody photographs for Instagram, but it can decide whether you open on time, pass an inspection or get stuck with a surprise bill after buying a business. Find out what your utility needs, quote it early and build it into the plan.

If the plumbing, a refit or a business purchase needs funding, that’s what we do for cafés, restaurants, bakeries and takeaways. Enquiring takes about 60 seconds, and it won’t leave a mark on your credit file. There’s no credit check when you first enquire. Your details aren’t passed around a crowd of lenders, so you won’t be fielding calls from people you’ve never heard of. A real person who understands commercial kitchens reads your enquiry, looks at your venue and rings you. Please fill the form in accurately, including your turnover, the quote you’ve received and any existing debts, so we can find the right fit first time.

See if your café qualifies →