Some of Port Phillip Bay’s most scenic beaches have also emerged as its cleanest, with Santa Casa, Portsea and Mt Martha Surf Life Saving Club topping the latest rankings for water quality over the summer season.
New data from the EPA Beach Report has ranked bay beaches based on the number of Good, Fair and Poor water quality forecasts issued throughout summer 2025–2026. Black Rock, Half Moon Bay, Sandringham and Eastern Beach also featured among the top performers.
At the other end of the list were Carrum, which ranked last at 36th, followed by Frankston Surf Life Saving Club, Frankston Coast Guard, Mordialloc and Port Melbourne.
The results reflect a broader trend across the bay, where beaches located further from Melbourne’s most densely populated areas tend to record better water quality.
EPA Chief Environmental Scientist Dr Jen Martin said seasonal conditions also played a role in the results.
“The data shows that, despite an overall improvement in bay water quality over the last four decades, it is generally the beaches farthest from the most densely populated urban areas that perform best,” Dr Martin said.
“Summer 2025-2026 was drier than average overall, with January the month driest of the season,” she said.
Dr Martin explained that rainfall can have a significant impact on water quality around the bay.
“As heavy rain washes pollutants from Melbourne’s streets and footpaths through the stormwater drain system to our creeks and waterways, ultimately ending up in the bay, having drier weather usually leads to an improvement in the bay’s water quality.
“Water pollution after rain might aggravate skin conditions or even cause gastro. Given time, it dilutes and water quality improves.”
Despite the occasional poor forecast, Dr Martin said long term monitoring shows the bay remains generally clean given the urban areas surrounding it.
EPA’s Beach Report continues to provide twice daily water quality updates for beaches around Port Phillip Bay throughout autumn.
