Oatley Bay Baths and Carss Point Baths continue to stand out for poor recreational water quality.
They were exceptions to the mostly Good and Very Good ratings given to swimming spots in St George and Sutherland Shire in the 2018-19 State of the Beaches Report.
The report, which was released on Sunday, revealed improvements at two locations.
Jibbon Beach in Port Hacking moved from Good to Very Good, while Gymea Bay Baths improved from Poor to Fair.
The report's findings for the region included:
- Coastal beaches: All Very Good apart from Boat Harbour, which was rated Good.
- Port Hacking: Jibbon Beach improved from Good to Very Good, and Gymea Bay Baths from Poor to Fair. All other locations remained Good.
- Botany Bay: All the baths were rated Good. Foreshores Beach, on the northern side of the bay, continued to be Very Poor.
- Lower Georges River: Oatley Bay Baths and Carss Point Baths remained Poor. All other locations were rated Good.
The report said gradings were in accordance with the National Health and Medical Research Council's 2008 Guidelines for Managing Risks in Recreational Waters.
"These beach suitability grades provide a long-term assessment of how suitable a beach is for swimming," the report said.
"The grades are determined from the most recent 100 water quality results (two to four years' worth of data depending on the sampling frequency) and a risk assessment of potential pollution sources.
The report said rainfall was the major driver of pollution to recreational waters, generating stormwater runoff and triggering untreated discharges from the wastewater treatment and transport systems.
Extended dry conditions had been experienced during the year, but there had also been several wet months on the coast.
The report said winter 2018 was the eighth driest for NSW on record, with average to well below average rainfall recorded for most coastal areas.
Above average rainfall was recorded in Sydney during June, but July and August 2018 were very dry.