Water Systems Overview: Melbourne Water

Executive overview

Key findings

509 billion liters: water supplied by Melbourne Water in 2024-25, the highest of the nine years from 2016-17

69.3%: storage level on 1 September 2026, after a low of 63.4% on 1 June 2026

150 GL: desalinated water ordered for 2026-27, the plant's maximum ordering level

A$7,307.7 million: capital expenditure benchmark for 2026–2031 set by the Essential Services Commission

Buyer relevance

Who the report is for

Water sector advisers and consultants

Use the institutional map to see which decisions sit with Melbourne Water, the retailers, the Essential Services Commission and the state.

Infrastructure contractors and suppliers

Read the major project table, from the Hobsons Bay Main Sewer to Cardinia Dam, with costs and status for each.

Investors and lenders

Set the A$7,307.7 million 2026–2031 benchmark against inflows, storage levels and the pending supply decision.

Urban planners and developers

Understand flood exposure for more than 200,000 properties and the drainage audit findings that affect growth areas.

Decision scope

Questions answered

How far have inflows to Melbourne's storages fallen?

Average inflows were 615 GL a year from 1913 to 1996 and 427 GL a year from 1997 to 2020.

How important is desalination now?

The 150 GL order for 2026-27 is about 29% of the 509 billion liters supplied in 2024-25.

Where is Melbourne's sewage treated?

In 2023-24 the Western Treatment Plant received 210,110 ML and the Eastern Treatment Plant 155,757 ML, about 57% and 43%.

Who decides on the next water source?

The state; its Water Security Taskforce is due to report in March 2027.

Inside the report

Inside the complete report

Executive Overview

1. Water Resource Profile

2. Governance and Institutional Framework

3. Infrastructure and Service Delivery

Strategic Outlook and Opportunities

Source Register

Public preview

What to watch next

1. Water Resource Profile

Storage levels through summer 2026/27; the following year's desalination order; residential use against the 150-liter target.

2. Governance and Institutional Framework

The taskforce report in March 2027 and the government's response; Melbourne Water's public reporting of growth-area drainage performance; any further statement on future ownership.

3. Infrastructure and Service Delivery

Completion of the Hobsons Bay Main Sewer in late 2026; Western Treatment Plant licence compliance in 2025-26; publication of the 2026–2031 Waterways and Drainage Investment Plan.

Strategic Outlook and Opportunities

The taskforce's recommendation and the government's response; storage levels and any restrictions over summer 2026/27; the following year's desalination order; Melbourne Water's FY2026 results.

Report page with a sewage treated series from 2017-18 to 2024-25, a service performance table and a major project table including trunk sewers, treatment plants and dam works. — Sample page · page 7 of 11
Section 3 lists sewage treated by year, service performance and the major projects with cost and status.

Included

What you receive

The complete PDF report: 11 pages, 6 sections, 12 tables and a register of 23 sources.

This edition

October 2026 edition.

Evidence & method

Evidence and method

The report draws on Melbourne Water annual reports from 2016-17 to 2024-25, Essential Services Commission price decisions, state water accounts and strategy documents, and Melbourne Water's supply, treatment, project and flood publications. Current status is checked against the 2026 Water Outlook, state government releases, an Auditor-General's audit and parliamentary proceedings.

Sources

23 sources, listed in the report's source register. Evidence current to 29 October 2026. Principal data periods: Operating data 2016-17 to 2024-25 and FY2025 audited results (years ending 30 June); storage levels to 1 September 2026; 2026–2031 regulatory period. Status checked against public sources on 29 October 2026. All currency is Australian dollars (A$)..

Evidence boundaries

This report uses authoritative source material available at the stated research cutoff. It distinguishes published facts, calculated values and analytical interpretation. No independent modelling is performed. Forward-looking analysis reflects published plans, documented trends and stated uncertainties. It does not constitute legal, financial, investment or engineering advice.

Lead analyst

Robert C. Brears

Founder, Our Future Water Intelligence

Robert C. Brears is a water-security specialist and author whose work examines utility governance, infrastructure investment, climate resilience and long-term water-system change for executive and policy audiences.

Decision-focused utility intelligence
Published water-policy author
Evidence-grounded system analysis

Buyer FAQs

Before you purchase

Who can use the report?

Licensed for internal use within one purchasing organization. The PDF and its contents may be shared with colleagues within that organization. External redistribution, resale and public publication are prohibited without permission.

How is the report delivered?

The PDF is available to download immediately after confirmed payment, through our secure delivery system.

Can my organization buy wider access?

Institutional purchasing: For invoice enquiries, multi-organization licensing or broader access requirements, contact Our Future Water Intelligence.