How we monitor water quality

Victoria has many different types of marine and freshwater environments. This includes bays, lakes, estuaries, coasts, catchments and wetlands.

There are challenges in sustaining the health of our water environments. These include:

• industrial discharges to wastewater from a single source, such as a pipe or a drain (point source discharges)
• diffuse pollution, such as stormwater, urban and agricultural run-off
• excess nutrient and sediment loads
• urban and industrial development
• introduced species that impact biodiversity
• climate change.
  

We regularly monitor water quality at locations across Victoria. We do this to:

• protect our water environments
• assess environmental conditions
• assess risks to human health.

We monitor:

• major bays and waterways
• beaches in Port Phillip Bay
• sites along the Yarra River.

Pollution often impacts beaches and rivers after storms, but it can also happen during dry weather.

Our monitoring helps us:

• measure water quality
• identify and investigate risks such as pollution
• guide improvements in water quality.
  

As well as monitoring water quality, we also:

• assess licensed discharges into water
• investigate pollution reports.

When we receive a water pollution report, we may respond by inspecting the impacted area and taking samples.

We use the data we collect through our monitoring to:

• inform our water quality forecasts on Check air and water quality
• issue water alerts and investigate when there's an issue affecting a specific waterway
• provide an annual summary of the water quality in Port Phillip Bay, Western Port and Gippsland Lakes and their catchments in our Report Card.

Our water quality forecasts and alerts help you make informed decisions about swimming. They can help prevent you from getting sick.

Results from our Report Card help guide initiatives, policies and projects to improve water quality and health.

Environmental water quality at our major bays and lakes

We collect water samples from 15 fixed sites across:

• Port Phillip Bay
• Western Port
• Gippsland 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.

These bays and lakes are the largest coastal water bodies in Victoria.

We analyse samples for:

• algae (measured by looking at chlorophyll-a)
• ammonia
• dissolved oxygen
• nutrients such as nitrogen, phosphorus and silicate
• pH levels
• salt levels (salinity)
• water clarity (measured by looking at total suspended solids and turbidity)
• water temperature.
  

This is a continuous dataset. It helps us understand long-term trends in environmental conditions in some of Victoria’s most stressed water systems. You can access this water quality dataset for Port Philip Bay, Western Port and the Gippsland Lakes on DataVic.

This dataset aligns with the water quality objectives for Victoria in the Environment Reference Standard. For example, a rating of Very Good or Good indicates that the water quality meets objectives. A rating of Poor or Very Poor indicates that the environmental condition of the water body is under stress.

Our annual Report Card combines these standards with the monitoring data to calculate an annual water quality index (WQI) score out of 10. This corresponds to a rating of Very Poor, Poor, Fair, Good or Very Good.

Recreational water quality at our beaches

All year round, we monitor water quality at 36 beaches in Port Phillip Bay. Most sites are located in front of lifesaving clubs, where people swim between the flags.

Beaches closer to stormwater drains or river mouths are at higher risk from stormwater pollution than other sites.

The biggest risk of illness comes from faecal contamination (poo). It can come from a range of sources, including:

• animal poo – for example, from dogs, birds and other wildlife
• faulty onsite wastewater management systems
• sewerage system leaks
• stormwater discharge.

Swimmers who swallow or inhale water with faecal contamination may become sick. Most at risk are:

• children
• older people
• people with a compromised immune system.
  

We take water samples and test them for enterococci. This group of bacteria is found inside warm-blooded animals. Enterococci are the best indicator for measuring pollution from faecal contamination at beaches.

It takes 24 hours to measure enterococci levels. We report results to the community the day after samples are collected. If the samples do not meet microbial water quality standards and there has not been any recent rain, we take a second sample.

We expect water quality to meet standards when there's been no recent rain or stormwater pollution.

The results from this sampling inform our water quality forecasts for 36 beach locations on Check air and water quality.

To view microbial water quality sampling results for our beach monitoring sites, visit DataVic. For more information on water quality forecasting, visit Water quality forecast ratings.

Monitoring recreational freshwater quality

We partner with Melbourne Water to forecast water quality at 4 locations along the Yarra River:

• Launching Place
• Healesville
• Warrandyte
• Kew.
  

Water samples are tested for bacteria found in faeces called E. coli. E. coli is an indicator for measuring pollution from faecal contamination in fresh water.

The results from this sampling inform our water quality forecasts for the Yarra River on Check air and water quality.

To view microbial water quality sampling results for Yarra River monitoring sites since December 2013, visit DataVic. For more information on water quality forecasting, visit Water quality forecast ratings.

Water quality standards and recreational water quality

We assess our marine and fresh water sampling results against water quality standards in the Environment Reference Standard.

We assess Beach and Yarra samples against recreational water quality standards. These also reflect advice from the National Health and Medical Research Council. The standards are based on scientific studies that link microbial levels in water with the risk of illness.

The standards mean we have thresholds to understand if there are levels that pose a health risk.