Grease Trap Installation Guide for Melbourne Businesses

Planning a Grease Trap Installation in Melbourne Installing a grease trap is a significant investment for any Melbourne food business — and one that requires careful planning, the right approvals, and qualified tradespeople. Whether you are fitting out a new commercial kitchen, upgrading an existing system, or responding to a compliance notice from Melbourne Water, this guide walks you through the entire process from initial planning to commissioning.

Step 1: Determine Your Requirements Before selecting a trap or engaging a plumber, you need to understand what your business actually requires. Several factors drive this:

Trade waste consent: If you already hold a trade waste agreement with Melbourne Water, it will specify minimum trap size, type and maintenance frequency. If you do not have one, you will need to apply before installation. Business type and FOG output: A high-volume restaurant generates far more fats, oils and grease than a small cafe. Your trap must be sized accordingly. Available space: In-ground traps need excavation area and ongoing vehicle access for pump-outs. Above-ground units and AGRUs need internal floor space. Budget: Costs vary significantly by trap type, size and site conditions. Our detailed grease trap sizing guide explains how to calculate the correct capacity using the AS 1546.1 methodology.

Step 2: Engage a Licensed Plumber In Victoria, all grease trap installations must be carried out by a licensed plumber who holds the appropriate registration with the Victorian Building Authority (VBA). This is a legal requirement — unlicensed installation is an offence and will void any compliance certification.

What to Look for in a Plumber Current VBA plumbing registration Specific experience with commercial grease trap installations Familiarity with Melbourne Water trade waste requirements Willingness to handle the permit and approval process Insurance coverage for commercial plumbing work Your plumber will prepare the installation design, including pipe sizing, fall gradients, trap location and ventilation — all of which must comply with AS/NZS 3500 (Plumbing and Drainage) and AS 4674 (Construction and Fitout of Food Premises).

Step 3: Obtain Approvals and Permits Grease trap installation in Melbourne typically requires multiple approvals:

Melbourne Water Trade Waste Consent All commercial food businesses discharging to Melbourne’s sewer system need a trade waste consent from Melbourne Water. This consent specifies the type and size of grease trap required, acceptable discharge limits and maintenance obligations. If you are a new business, apply well in advance — processing can take 4 to 8 weeks.

Council Building Permit For in-ground installations, a building permit from your local council may be required, particularly if the work involves excavation, structural modifications or changes to the building’s drainage system. Your plumber or building surveyor can advise on whether a permit is needed.

Plumbing Compliance Certificate After installation, your plumber must submit a compliance certificate to the VBA and your local council, confirming the work meets all regulatory requirements. This is a mandatory step — without it, the installation is not legally compliant.

Step 4: Site Preparation The extent of site preparation depends on the trap type:

In-Ground Trap Preparation Excavation of the pit to required dimensions (depth, width and length per trap specifications) Preparation of a compacted base — often a concrete pad for heavy traps Routing of drainage pipes from kitchen fixtures to the trap location Ensuring vehicle access for future pump-out trucks (minimum 3-metre-wide path) Managing soil and spoil disposal — your plumber or contractor should arrange this Above-Ground Trap Preparation Clearing the installation area inside the kitchen Ensuring the floor can support the weight of a full trap Providing drainage connections from relevant fixtures Ensuring adequate ventilation to manage potential odours Step 5: Installation Professional grease trap installation typically follows this sequence:

Positioning and levelling the trap unit Connecting inlet pipes from kitchen drainage fixtures Connecting the outlet pipe to the sewer line Installing access lids and ensuring they are sealed and secure Testing for leaks with a water fill test Backfilling and compacting around in-ground traps Installing any required ventilation or sampling points For in-ground traps, the process typically takes 2 to 5 days. Above-ground installations can often be completed in a single day.

Step 6: Commissioning and Inspection Once installed, the trap must be commissioned and inspected:

Your plumber conducts a final inspection and issues a compliance certificate Melbourne Water may inspect the installation as part of your trade waste consent activation The trap is filled with clean water to establish the initial water seal Maintenance schedules are set based on your consent conditions Timeline and Cost Expectations Typical Timeline Trade waste consent application: 4 to 8 weeks Plumber engagement and design: 1 to 2 weeks Council permit (if required): 2 to 4 weeks Installation: 1 to 5 days Total from start to commissioning: 8 to 16 weeks Cost Ranges for Melbourne Above-ground trap (installed): $800 to $4,000 In-ground trap 1,000L (installed): $4,000 to $8,000 In-ground trap 2,000-5,000L (installed): $8,000 to $20,000+ AGRU (installed): $8,000 to $25,000 These figures include the trap unit, excavation (where applicable), plumbing, backfill and compliance certification. Complex sites — such as those requiring rock excavation, deep trenching or structural modifications — will be at the higher end.

Compliance with Melbourne Regulations A properly installed grease trap must comply with:

AS 1546.1 — sizing requirements AS/NZS 3500 — plumbing and drainage standards AS 4674 — food premises construction and fitout Melbourne Water trade waste consent conditions EPA Victoria — Environment Protection Act 2017 general environmental duty Local council building regulations Ready to Install? Local contractors manage grease trap installations across Melbourne, from initial sizing and design through to commissioning and ongoing maintenance. Check the plumber’s registration on the VBA register, and ask who will handle the approval process. Contact us today and we’ll pass your enquiry to a local contractor for a free installation quote.