Flood water is brown and smelly for a reason - it's contaminated - and a water quality expert from Western Sydney University (WSU) is urging people to steer clear of the murky torrents for the sake of their health.
With sewage systems around Sydney overflowing due to a three-day rain bomb, as well as dead animals, chemicals and other pollutants being mixed in to stormwater runoff, flood water is a toxic soup that can make people sick.
This is the message being spread by environmental expert and senior lecturer, Dr Ian Wright from the WSU School of Science, based at Hawkesbury campus.
Dr Wright said "it stresses me out" to watch news footage of people playing in flood water, including jet-skiing in it.
"There are enormous volumes of runaway sewage in flood water, not to mention the dead animals and urban waste," Dr Wright said.
"So many sewerage systems do not cope in wet weather. Water leaks in, the system doubles or triples, and it overflows all over the place. You start to see sewer covers popping up - I think it is a sage warning."
There are enormous volumes of runaway sewage in flood water, not to mention the dead animals and urban waste.- Dr Ian Wright
Hawkesbury City Council's waste water treatment plant at Windsor was switched off on Monday, because of flooding.
Council said it was conducting regular checks on manhole covers in local streets and advised the community to refrain from any water activities in the sewer catchment areas including Windsor, South Windsor, McGraths Hill, Pitt Town, Bligh Park, Windsor Downs and Clarendon.
According to WorkSafe Queensland, the risks of working with sewage include gastroenteritis with symptoms of nausea, vomiting and diarrhoea; skin infections if germs get into a cut, abrasion or other break in the skin; and even hepatitis A.
Dr Wright said the situation was worse when people's immune systems were down, as they were likely to be with the ongoing stress of dealing with four floods in two years.
"I'm so worried for people affected by their third or even fourth flood in 18 months. How much can people cope with?" Dr Wright said.
"Recovery will be harder than March 2021 or March 2022 as in the middle of winter it will be weeks and months before things can dry out."
He said that mould would be "an enormous problem" this time around and, if people were carrying Covid or flu, the situation would be worse again.
He urged Hawkesbury locals to reach out to politicians to let them know of the extreme circumstances they were facing during the flood.
Hawkesbury City Council advised people who come in contact with flood water while cleaning-up after a flood to do the following to prevent illness:
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