Water quality data and reports

Check air and water quality to see water quality forecasts for beaches in Port Phillip Bay and the Yarra River.

We monitor marine and fresh water quality at locations across Victoria. We use the data we collect to report on:

the environmental condition of our waterways through Report Card
risks to human health through the Beach and Yarra Watch program.

Learn more about how we monitor water quality.

You can get access to raw and summary data for water quality throughout Victoria at DataVic.

Annual water quality reports

Report Card provides a 12-month (between July and June) summary of water quality for these waterways and their catchments:

Port Phillip Bay
Western Port
Gippsland Lakes.

Report Card also shows the trend in water quality for each catchment dating back to 2000.

We collect samples from marine bays and lakes. The Department of Energy, Environment and Climate Action (DEECA) collects samples from rivers and streams in Gippsland. Melbourne Water collects samples from waterways in greater Melbourne.

We collate the sampling data and use it to calculate an annual rating. This rating is based on key water quality indicators.

We benchmark key water quality indicators against Victorian environmental quality objectives in the Environment Reference Standard. We combine these to calculate an overall water quality index (WQI) score out of 10, corresponding to a rating from Very Poor to Very Good.

Water quality index scoring categories

WQI score	Rating	Description
8 to 10	Very Good	high-quality waterways generally not impacted by pollution
6 to 8	Good	meets Victorian water quality objectives
4 to 6	Fair	shows some evidence of stress
2 to 4	Poor	under considerable stress
0 to 2	Very Poor	under severe stress.

In general, water quality is Very Good or Good in the elevated areas where most rivers originate. Water quality declines to Poor or Very Poor as the rivers move through rural, agricultural and urban low-lying areas.

In the bays and lakes, water quality is Very Good or Good in areas that mix with the open ocean.

Overall, water quality has stayed relatively steady. This is even though population pressures have increased over time.

These are the annual snapshots for the last 5 years:

Report Card 2022–2023

In 2022–23, water quality in the bays, lakes and waterways changed from previous years. There were improvements in Gippsland Lakes and Western Port and a decline in the Port Phillip Region.

Rainfall in central Victoria was well above average. High rainfalls in the Port Phillip Bay catchments during spring 2022 resulted in localised flooding, increasing sediment and nutrient loads to Port Phillip Bay. This resulted in Fair water quality scores for 4 of the 6 bay sites.

Annual Report Card - Port Phillip, Western Port and Gippsland Lakes (July 2022 to June 2023)

Report Card 2021–2022

In 2021–22, water quality declined from Good to Poor in the Gippsland Lakes.

High rainfall in this region resulted in flooding in spring 2021, delivering high loads of nutrients to the Gippsland Lakes. Warmer-than-average summer water temperatures triggered a blue-green algal bloom in the Gippsland Lakes. This persisted from February to May 2022.

Annual Report Card – Port Phillip, Western Port and Gippsland Lakes (July 2021 to June 2022)

Report Card 2020–2021

Conditions for 2020–21 were similar to previous years across the bays and lakes.

COVID-19 travel restrictions in 2020 meant reduced monitoring in Port Phillip Bay, Western Port and the Gippsland Lakes. In particular, there is no data for the Gippsland Lakes from July to November. While the number of samples collected was above the minimum requirement across the 12-month reporting period, there is a significant time gap in results in the Gippsland Lakes during winter and spring.

Annual Report Card - Port Phillip, Western Port and Gippsland Lakes (July 2020 to June 2021)

Report Card 2019–2020

In East Gippsland, there was a decline in water quality at some sites along the upper Tambo and Mitchell rivers. This was due to long-term reduced rainfall. Monitoring results showed that the 2019–20 bushfires temporarily impacted water quality at some East Gippsland sites. However, the Gippsland Lakes catchment maintained Very Good water quality overall.

Annual Report Card - Port Phillip, Western Port and Gippsland Lakes (July 2019 to June 2020)

Report Card 2018–2019

Dry conditions across Victoria in 2018–19 reduced stream flows. This resulted in less freshwater input to the bays and lakes, causing marginally better water quality. However, some shallow locations – such as Corinella in Western Port, Lake Wellington in the Gippsland Lakes, and waterways in urban and rural settings – continued to be influenced by pollutants in the sediments.

Annual Report Card - Port Phillip, Western Port and Gippsland Lakes (July 2018 to June 2019)

Beach and Yarra Watch

We assess water quality for recreational use through the Beach and Yarra Watch program. We use measurements of microbial water quality taken at popular recreational sites in Port Phillip Bay and the Yarra River.

Port Phillip Bay

All year round, we monitor microbial water quality at 36 beaches in Port Phillip Bay. We test the samples for enterococci, a bacteria found in faeces. Enterococci are the best indicator for measuring pollution from faecal contamination at beaches.

To view microbial sampling results for our marine water sites since December 2013, visit DataVic.

Yarra River

All year round, EPA and Melbourne Water monitor water quality at 4 Yarra River sites. We test the samples for bacteria found in faeces called E. coli. E. coli is an indicator for measuring pollution from faecal contamination in fresh water.

To view microbial water quality sampling results for Yarra River monitoring sites since December 2013, visit DataVic.

Season water quality sampling results

The Beach and Yarra Watch season summary provides microbial sampling results for the summer season. It also provides an analysis of the accuracy of water quality forecasting from Beach and Yarra Watch data.

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