State efforts to play down the presence of "forever chemicals" in a major city's drinking water supply were made without a proper testing regime, an inquiry has found.
Sydney Water claimed in June 2024 there were no known PFAS hotspots within its drinking water catchments as citizen-led testing pointed to concerning levels of the man-made chemicals in water supplies.
But the NSW parliamentary inquiry found the agency responsible for delivering potable water to 5.3 million people "did not perform an appropriate level of due diligence" before making its claims.
"The public should have the utmost faith that the relevant government bodies are keeping our drinking water and waterways safe," the inquiry committee chair, NSW Greens MP Cate Faehrmann, said on Thursday.
"(But) it soon became apparent that government agencies tasked with protecting public health and water quality had been unable to keep pace with the spread of PFAS."
As a result of Sydney Water's delayed action, the NSW government has been urged to regularly test water for PFAS chemicals.
PFAS, or per- and polyfluoroalkyl substances, are a group of 15,000 toxic, synthetic chemicals used for their resistance to heat, stains and grease.
Science around the chemicals is evolving but they are associated with increased levels of cholesterol, reduced kidney function, lowered birth weight in babies and other health issues, the government's environmental health standing committee found.
In mid-2024, high-level contamination was detected in the drinking water catchment that serves about 30,000 people in the NSW Blue Mountains region.
PFAS levels were about 300 times higher than Sydney's main drinking water source but still met then-guidelines for safe drinking water.
Water authorities have blocked off supply from a contaminated dam.
Blue Mountains locals are pushing for publicly funded blood tests, which the inquiry has backed .
A major river in central-west NSW was also discovered to have PFAS-contaminated foam, but the inquiry found the NSW Environment Protection Authority failed to erect signs warning against swimming and fishing.
Tests on carp in the Belubula River also found high-levels of PFAS, but the authority took more than eight months to test other fish in what was branded as an "unacceptable" delay by the inquiry.
PFAS chemicals are found in a range of everyday objects from dental floss to non-stick cookware to firefighting foam.
The inquiry has recommended the phase-out of all non-essential uses of the chemicals in consumer, commercial and industrial products by the end of the decade.
