Authorities have revealed what triggered a country town's water crisis on Christmas day.
Heavy rain and "intense weather" is believed to have sparked a fault with Elmore's water treatment plant's alarm system which caused it to stop running.
From about 1.30pm on Christmas Day, the storms apparently set off the alarm which caused the town's clear water storage tank to be drained.
Tap water supplies from at least that time were untreated and potentially contaminated.
The town's treatment plant is supplied from two groundwater bores.
The emergency saw urgent online alerts issued and door knocking on Boxing Day to warn residents.
There are about 850 people in Elmore, located on the Northern Highway between Bendigo and Echuca, and the town recorded around 50mm of rain during a soggy Christmas across the state.
Free water is being supplied by a Coliban Water trailer from the town's water tower and supplies of free bottled water are on hand.
"We are encouraging all community members to use our water trailer in the first instance, before taking bottled water," the authority said today.
Coliban Water said it consulted with the Department of Health before advising residents not to drink the untreated tap water until further notice.
Boiling the water was not recommended either.
Coliban Water staff are still door knocking homes across the town today (Wednesday) to warn residents of the water danger.
"If you have an elderly or vulnerable neighbour, please check on them, or let us know so we can support them."
Although the plant is back in operation and Coliban Water said it would be adding chlorine to the water supply as a short term fix, it may be some time until normal operations can be restored.
Until an all clear is issued residents have been told to use the emergency water supplies.
"We expect it will be several days before Elmore's water network returns to normal, and before the 'do not drink' advisory can be lifted," the authority said today.
Residents have been told the tap water should not be used for drinking, washing or preparing food, preparing baby formula, brushing teeth or making ice.
They have been advised the tap water can be used for toilet flushing, bathing (ensure you do not ingest the water) and washing machine use.
"Boiling water will not remove any potential contaminants that may enter the distribution system if there is pressure loss in the system."
The health alert also said "if you are concerned that you may have been affected by contaminated water please seek medical advice. Inform your GP of this advisory."