How do you connect to a Sydney Water sewer main?

You need Sydney Water's written approval before connecting to their sewer main. Apply through Sydney Water Tap in. They assess applications within 21 days. Listed constructors handle new wastewater connection points to gravity sewer mains. Licensed plumbers join private plumbing to existing connection points. Sydney Water must do the work if their pipe is larger than DN 200 or your connection is bigger than DN 50.

What is a Section 73 Compliance Certificate from Sydney Water?

A Section 73 Compliance Certificate confirms your development or subdivision has adequate water, wastewater, and stormwater services. You need one before council issues an occupation certificate. Apply through a Water Servicing Coordinator or Sydney Water Developer Direct ($1,164.31 inc GST for minor works). Sydney Water issues a Notice of Requirements within 60 days, valid for 12 months.

What size grease trap does a commercial kitchen need for Sydney Water?

Sydney Water requires grease traps sized to the maximum hourly flow rate of the business, with a maximum capacity of 5,000 litres per unit. Shopping centres with less than 30,000 litres total capacity need multiple communal grease traps. Centres with 30,000 litres or more need centralised pre-treatment like dissolved air flotation. Traps must drain by gravity and have clearance above equal to the trap depth.

What pipe junctions does AS/NZS 3500.2 require for sewer connections?

AS/NZS 3500.2:2025 requires 45-degree Y junctions for all connections to graded sewer drains. 88-degree sweep junctions are not permitted on graded drains. Where a smaller branch pipe connects to a larger drain, the branch invert must sit at least 10 mm above the soffit of the receiving pipe.

Sewer Connection and Sydney Water Requirements

Q: How much does a Sydney Water trade waste agreement cost?

Commercial trade waste permit applications cost $555.08 (low complexity) to $809.60 (high complexity). Quarterly management fees start at $30.66 for the first process. Waste quality charges vary by industry: high-strength food waste with pre-treatment costs $3.766 per kilolitre, while high-strength food without pre-treatment costs $19.165 per kilolitre. These are 2025-26 IPART-regulated fees.

Section 1

What You Need to Know

Every building in Sydney Water's network needs written permission before it connects to the sewer. This applies to new developments, subdivisions, and any business that sends trade waste down the drain. The process runs through Sydney Water Tap in, and it touches three things: the physical pipe connection, the Section 73 compliance certificate, and (for commercial sites) a trade waste agreement.

Miss any one of these and you will not get your occupation certificate. AS/NZS 3500.2 governs how the pipe work gets designed and installed. Sydney Water's own technical requirements sit on top of the standard.

Section 2

The Rules

You must get Sydney Water's written approval before you connect any pipe to their sewer main. Apply through Sydney Water Tap in. They assess applications within 21 days (Sydney Water Connection Policy SW108)
Listed constructors handle new wastewater connection points to gravity sewer mains. Licensed plumbers join private plumbing to existing connection points. Sydney Water must do the work if their pipe is larger than DN 200 or your connection is bigger than DN 50 (Sydney Water Connections Policy)
Acceptable pipe materials: PVC, DICL, and CICL. Drain junctions must use 45-degree Y junctions. 88-degree sweep junctions are not allowed on graded drains (AS/NZS 3500.2:2025, Cl 3.5)
Where a smaller branch pipe connects to a larger drain, the branch invert must sit at least 10 mm above the soffit of the receiving pipe (AS/NZS 3500.2:2025)
Every development or subdivision needs a Section 73 Compliance Certificate before council issues an occupation certificate. Developer Direct costs $1,164.31 inc GST for minor works. Notice of Requirements issued within 60 days, valid for 12 months (Sydney Water Act 1994, s73)
Any business discharging trade wastewater needs a trade waste agreement. Commercial permit applications cost $555.08 to $809.60. Serious breaches carry fines up to $250,000 (Sydney Water Trade Waste Policy)

Section 3

What This Means in Practice

A standard commercial development - say a two-storey retail building with a cafe on the ground floor - hits all three requirements. You need a sewer connection approval for the building drain, a Section 73 certificate for the development, and a trade waste agreement for the cafe's kitchen waste.

Start the Section 73 application early. The Notice of Requirements takes up to 60 days, and any construction work on Sydney Water assets must be done by a listed constructor. For minor works (single wastewater connection, sewer main extension under 25 m, pipe protection measures), you can apply through Developer Direct. Major works - buildings over 4 storeys, subdivisions with 5 or more lots, sites in pressure or vacuum sewer areas - need a Water Servicing Coordinator.

The physical connection is where AS/NZS 3500.2 meets Sydney Water's own specs. Your property drain connects to the boundary trap, which then connects to Sydney Water's sewer main. The boundary trap is your responsibility. Everything downstream of the connection point is Sydney Water's. Use 45-degree Y junctions only. Maintain the minimum grades from AS/NZS 3500.2: 1.65% for DN 100 and 1.00% for DN 150. Position the connection so the property drain flows by gravity to the sewer main - pumped connections add cost, maintenance, and a failure point.

Section 4

Key Design Decisions

Trade Waste Agreement Type: Commercial Permit vs. Industrial Consent

Commercial permits cover restaurants, cafes, car washes, laundromats, and mechanical workshops. Industrial consents cover manufacturing, textiles, petroleum, and chemical processing. The quarterly management fee for a commercial permit starts at $30.66 for the first process. Industrial consents range from $659.21 to $5,051.79 per quarter depending on risk index.

Trade-off: Industrial consents come with random testing and stricter discharge limits, but they allow higher-strength effluent. Commercial permits are simpler and cheaper, but the discharge limits are tighter and you must install pre-treatment.

Pre-Treatment: Grease Trap vs. Centralised System

Single-tenancy food businesses need a grease trap sized to their maximum hourly flow rate. Maximum capacity per trap is 5,000 L. Shopping centres with less than 30,000 L total capacity use multiple communal grease traps. Centres with 30,000 L or more need centralised pre-treatment like dissolved air flotation.

Trade-off: Individual grease traps are cheaper to install but need regular pump-outs by a Wastesafe transporter. Centralised systems cost more upfront but handle higher loads and simplify maintenance across multiple tenancies.

Connection Route: Developer Direct vs. Water Servicing Coordinator

Developer Direct costs $1,164.31 inc GST and works for minor works like a single sewer connection or a main extension under 25 m. A Water Servicing Coordinator charges market rates (typically $3,000 to $8,000) but handles major works and complex sites.

Trade-off: Developer Direct is cheaper and faster for simple jobs. But if your project triggers major works - 5+ lots, 4+ storeys, pressure sewer area - you must use a coordinator. Starting with Developer Direct and finding out mid-process that you need a coordinator wastes time and money.

Oil-Water Separator Sizing

Automotive workshops, service stations, and car washes need oil-water separators. Minimum sizes: 1 kL/hour for most applications, 750 L working volume for service station collection wells, and 500 L operating capacity for panel beaters and car washes. Undersizing means discharge limit breaches and non-compliance fees of $141.23 per event, plus potential fines up to $250,000.

Trade-off: Oversizing adds capital cost but gives headroom for future expansion and keeps you well inside discharge limits. Undersizing saves money now but risks non-compliance from day one.

Section 5

Who Needs to Know What

For Contractors

Get the junction type right. Sydney Water and AS/NZS 3500.2 both require 45-degree Y junctions for connections to graded sewer drains. Do not use 88-degree sweep junctions - inspectors will reject the work. Where your branch pipe is smaller than the main, keep the branch invert at least 10 mm above the soffit of the receiving pipe.

Install grease traps as close to the source (kitchen) as possible. They must drain by gravity to the sewer - pumped connections to grease traps are discouraged and create maintenance problems. Leave clearance above the trap equal to the trap depth so the Wastesafe transporter can access it for pump-outs. Do not add solvents, enzymes, bacteria, or odour control agents to grease traps. Sydney Water bans all of these. Sink-to-sewer units, food waste disposers, and garbage grinders are also banned.

Before you backfill, check that your boundary trap is accessible and that all pipe grades meet the minimums in AS/NZS 3500.2 (1.65% for DN 100, 1.00% for DN 150). Sydney Water inspects some plumbing installations, including tanks, pumps, and wastewater treatment equipment. A failed inspection means rework, delay, and cost.

For Developers

Budget 3 to 4 months for the full Section 73 process: 60 days for the Notice of Requirements, plus construction and inspection time. Start the application at DA stage, not after approval. The Notice of Requirements is valid for 12 months - if your project runs longer, you will need to reapply and pay the fees again.

Trade waste agreements are separate from the Section 73 certificate. If your tenants will include food businesses, automotive workshops, or any operation that generates trade wastewater, you need a trade waste agreement in place before they start operating. The application costs $555.08 to $809.60 depending on complexity. Quarterly management fees start at $30.66. Waste quality charges vary by industry - high-strength food waste without pre-treatment costs $19.165 per kilolitre, compared to $3.766 per kilolitre with pre-treatment. That gap pays for the grease trap within months.

For Architects

The boundary trap location drives the building's sewer layout. Work with the hydraulic engineer to confirm the connection point and invert levels during schematic design. Every horizontal drain run needs fall - 1.65% for DN 100 means 16.5 mm per metre. A 15 m run from a kitchen to the boundary trap drops 247.5 mm before you add the pipe diameter. That vertical space must exist in the slab zone or under the ground floor.

If the building has food tenancies, allow space for grease traps. Each trap needs a flat, accessible location with clearance above equal to the trap depth. It needs gravity drainage to the sewer and vehicle access for the pump-out truck. These constraints often conflict with car park layouts and loading docks, so resolve them early.

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Section 6

References

AS/NZS 3500.2:2025, Plumbing and drainage — Part 2: Sanitary plumbing and drainage
Sydney Water, Policy for Connecting to Sydney Water Systems (SW108)
Sydney Water Act 1994 (NSW), Section 73 - Compliance Certificates
Sydney Water, Technical Requirements and Work Instructions for Minor Works Sewer
Sydney Water, Commercial Trade Wastewater Requirements
Sydney Water, Grease Traps Installation Requirements
Sydney Water, Trade Wastewater Fees 2025–26 (set by IPART)
National Construction Code 2022, Volume Three — Plumbing Code of Australia