Queensland residents connected to the Bellview Estate, Cassowary Heights, and north and south Millstream water supply schemes are being warned to boil their water to avoid potentially becoming sick.
A boil water notice has been issued to those residents as heavy rain continues to lash northern Queensland ahead of forecast cyclones.
Experts say the severe weather is making usual water treatment methods impossible in the affected areas.
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Water for Bellview Estate is supplied from Vine Creek, in Cassowary Heights it comes from South Cedar Creek, and in north and south Millstream water is supplied from The Millstream.
Water from all of these sources is screened and chlorinated before it reaches reservoirs and properties. But when storms hit the waterways, the “high turbidity” — or cloudiness — of the water means chlorination does not work.
Communities affected are asked “to reduce consumption so the stored and treated water is not depleted”
“If the stored supply runs out, boil water notices are issued,” Tablelands Regional Council said.
“Residents at these properties must boil water for consumption until further notice,” the council said on Tuesday.
“Consumption of unboiled water could lead to illness, especially for vulnerable people such as the very young, elderly and those with weak immune systems.”
The boil water notice will remain in place until Queensland Health is confident there is no public health risk remaining.
Properly boiled water should be heated until a continuous and rapid stream of air-bubbles is produced from the bottom of a pan or kettle.
“Kettles with automatic cut-off switches are suitable and variable temperature kettles should be set to boil,” the council said.
“After heating, water must be allowed to cool before using it, and be stored in a clean, closed container for later use.”
Boiled water should be used for drinking, brushing teeth, washing and preparing food or beverages, preparing baby formula, making ice, and bathing babies and toddlers.
Unboiled water can be used for showering and bathing for those who can avoid getting water in their mouth.
It can also be used for washing dishes, clothes and for flushing toilets.
The Tablelands Regional Council urged affected residents made aware of the boil water notice to notify neighbours and other residents who may be affected.
Anyone who believes they have consumed contaminated water is urged to contact 13 43 25 84, or their local doctor or hospital.
Residents can also sign up for the Early Warning Network to receive email or SMS alerts when there is a disruption to water services.