People living at two rural Victorian properties have been told their groundwater has been contaminated by chemicals from a Country Fire Authority training facility.
The water supply in Penshurst was given the all clear earlier in the month but further testing has shown contamination in groundwater.
The department of health is assessing the potential risk to residents who may have "inadvertently drunk affected bore water," the Environment Protection Authority says in a statement.
The residents on two properties were advised that all use of bore water should be avoided and were offered alternative water sources if required.
A chemical contamination scare at the CFA training facility outside the town forced 700 residents to drink bottled water in July.
The same chemical forced the permanent closure of the Fiskville training facility.