Water and soil samples are being taken by the Environmental Protection Authority in Rochester over concerns dangerous chemicals and bacteria could be lingering in the town.
Around 1,000 properties were inundated by floodwaters on October 14 in Rochester.
Although the waters have subsided, stagnant water and puddles remain in parts while the ground is muddy in most areas.
Rainy conditions this week also have residents worried that conditions could worsen.
"We're also checking for total petroleum hydrocarbons because the flood waters have inundated petrol stations and industry, and some of those oils would have been flushed into the water," Mark Taylor, chief environmental scientist at the Victorian Environment Protection Authority (EPA), said.
"We're also doing pesticides because a lot of water has drained from agricultural land.
"And we're going to measure for pathogens like E. coli because that's an indicator for a myriad of pathogens we can find in the water."
Professor Taylor says the largest risk for residents is E. coli because of the illness it can cause residents.
"It happens when there are leakages from sewerage systems and flushed in from faeces from animals." he said.
"It's already been detected around Maribyrnong where it also flooded."
There have been several anecdotal reports of gastro in the Rochester area and there were reported cases of COVID-19 at the relief centre last week.
The EPA results will be known later this week.
Residents relieved
Rochester resident Joanne Speight is keen to find out the results.
"There's still a few of us living around the town in caravans and whatnot. There's so much to do with the clean-up; just when you think you're onto it, there's mould growing," she said.
"I'm still buying bottled water; I'm told you can drink it but I'm not comfortable yet.
Fellow Rochester resident Murray Whiteford has been boiling his water as a precaution.
"I'm glad the EPA is doing it because I'd like to know if the water is drinkable or not," he said.
"The clean-up is going slowly but we're getting there, there's a lot more to throw away than I thought."
