Management

In Greater Sydney, WaterNSW supplies raw water from its network of catchments, dams and waterways to major customers, including Sydney Water, which treats and distributes drinking water to more than five million people across Sydney, the Blue Mountains and the Illawarra.

WaterNSW also supplies raw water to local water utilities, including Wingecarribee Shire Council, Goulburn Mulwaree Council and Shoalhaven City Council. These utilities treat the water and supply safe drinking water to their communities.

The Australian Drinking Water Guidelines (ADWG) apply to water intended for drinking, including water supplied to Greater Sydney communities. The ADWG framework promotes a multiple-barrier approach to managing drinking water quality. Protection of source water catchments is recognised as the first and most effective barrier, helping to reduce risks before water reaches treatment plants.

In Greater Sydney, this approach is supported by WaterNSW’s management of declared drinking water catchment areas, including the Special Areas surrounding key reservoirs. These protected areas help minimise the impact of pollutants, sediment and debris from human activity and land use change, supporting the long-term quality of Sydney’s source water supplies.

WaterNSW manages Sydney’s drinking water catchments and storages with a strong focus on protecting raw water quality. For some substances, including metals, pesticides and synthetic organic compounds, raw water is expected to meet relevant ADWG health-based guideline values before treatment. This makes catchment protection, monitoring and proactive risk management essential.

We have an extensive monitoring program to ensure the best quality raw water is delivered to Sydney Water and councils for treatment. WaterNSW monitors water in the lakes and rivers. This monitoring allows us to monitor what is happening across the system and determine how to supply the best available quality water for treatment.

WaterNSW undertakes extensive water quality monitoring across rivers, reservoirs and waterways throughout the catchment. This monitoring helps identify emerging risks, track changing conditions and support the delivery of the best available raw water quality for treatment.

WaterNSW has developed a Water Quality Policy (PDF, 139.68 KB), which demonstrates our commitment and accountability relating to water quality for the supply of water to our customers across Greater Sydney and Fish River Supply Scheme.

Within the Fish River Water Supply Scheme, WaterNSW manages raw water quality and supplies raw water to Oberon Council for treatment and supply to local communities. WaterNSW also operates the Duckmaloi Water Filtration Plant, which supplies treated drinking water to Lithgow City Council for distribution to communities across the region, including the towns and villages of Lithgow, Wallerawang, Portland, Capertee and Rydal.

Drinking water produced by the Duckmaloi Water Filtration Plant meets the requirements of The Australian Drinking Water Guidelines (ADWG).

WaterNSW has developed a Water Quality Policy (PDF, 139.68 KB), which demonstrates our commitment and accountability relating to water quality for the supply of water to our customers across Greater Sydney and Fish River Supply Scheme.

Across regional New South Wales, WaterNSW supplies raw water to support communities, industry, agriculture and the environment. This water is provided to local water utilities and councils for treatment and distribution as drinking water.

In regional areas, WaterNSW supports drinking water suppliers in protecting public health by identifying, assessing and communicating raw water hazards and risks. This information helps suppliers understand changes in source water quality and supports the implementation of appropriate treatment and risk management measures.

WaterNSW also monitors river and waterway health through the Surface Water Assessment and Monitoring Program. WaterNSW undertakes blue-green algae monitoring through the Regional Algal Coordinating Committee and issues alerts when blue-green algae is detected, providing timely information to water users and drinking water suppliers about potential risks.

Raw water for drinking water suppliers in Regional NSW

WaterNSW's Operating Licence 2024-2028 includes requirements to support drinking water suppliers that source water from regulated rivers and WaterNSW storages across regional New South Wales.

These requirements strengthen source water risk management by improving understanding of water supply systems, hazards and risks; enhancing early warning arrangements; expanding access to raw water quality information; and supporting risk-based monitoring.

WaterNSW supports informed decision-making through monitoring, data sharing, notifications and collaboration on raw water quality risks. Drinking water suppliers remain responsible for treating raw water and ensuring the safety of drinking water within their own supply systems.

WaterNSW's Policy on raw water quality for drinking water suppliers (PDF, 174.97 KB) outlines how WaterNSW supports drinking water suppliers in managing risks associated with the raw water it supplies.

This policy does not apply to Greater Sydney drinking water supplies (including Sydney Water, Wingecarribee, Goulburn Mulwaree and Shoalhaven), Hunter Water, or water sourced from unregulated rivers or groundwater.

Service commitments to drinking water suppliers

WaterNSW’s service commitments to drinking water suppliers that receive raw water from WaterNSW, outlined in Clause 20 of the Operating Licence 2024–2028, include:

• Setting out the regional water quality and water quantity parameters used to support advance notifications
• Summarises the types of advance notifications covered by the early warning system

Water quality parameters

Water quality parameters are measurable characteristics of raw water that help assess water quality and identify potential risks to drinking water supplies. These parameters can be used to establish notification thresholds and provide early warning of changing conditions, enabling drinking water suppliers to adjust treatment processes, monitor risks and respond proactively to water quality events.

Key indicators for providing early warning of changes in raw water quality:

• turbidity
• temperature
• conductivity
• blue-green algae (potentially toxin-producing cyanobacteria)
• other locally relevant water quality parameters identified through WaterNSW's

Raw Water Quality Safety Guides, which are being developed in collaboration with each drinking water supplier.

When establishing thresholds, consideration is given to the treatment capability of the drinking water supplier, the characteristics of the source water and upstream river systems, and other factors that may influence raw water quality.

Site-specific thresholds for these parameters, together with any additional locally relevant indicators, are being progressively developed through Raw Water Quality Safety Guides for individual drinking water suppliers.

Water quantity parameters

Water quantity and operational parameters help provide early warning of changes in river flows, storage conditions or water supply system operations that may influence raw water quality or water availability. This information supports drinking water suppliers in understanding potential impacts and preparing for changing source water conditions.

These include, but are not limited to:

• flood notifications
• high regulated releases
• temporary water restrictions
• environmental flow notices
• storage volumes
• river flows and levels
• forecast rainfall
• operational updates, including temporary restrictions and flow announcements

Advance notifications summary

Types of advance notifications covered by WaterNSW’s early warning arrangements include the following.