A SERIES of incidents that turned creeks and stormwater drains bright blue, green or orange has prompted a call to plumbers and other tradies to be extra careful with the coloured marker dye they use in their work.

EPA Victoria said the dye, called fluorescein, is non-toxic but very concentrated, so even where it doesn’t affect the environment, it can still cause problems by diverting EPA investigators from more serious pollution.

EPA North East regional manager, Renee Palmer, said it can also be distressing for communities and Traditional Owners to see natural waterways stained an unnatural colour.

“Fluorescein is most often used by plumbers to check pipe connections or spot leaks,” Ms Palmer said.

"It is useful and non-toxic, but it is also highly concentrated, so it’s easy to overdo it.

“EPA will investigate any contaminant in a waterway in case it’s a hazardous chemical, but this year we’ve responded to numerous incidents involving fluorescein that took up investigators’ time and could easily have been prevented.

“That means tradies being extra careful when using fluorescein.

"If you accidentally use too much or notice it entering the stormwater system, report it to EPA.”

The recent incidents involving fluorescein have provided a visual demonstration of how the community’s streets, gutters and drains are pathways to our waterways.

“Anything you wash into a stormwater drain will end up in our creeks, rivers and oceans,” Ms Palmer said.

"EPA will investigate and can issue fines, but prevention is always a better protection for the environment.

“A little fluorescein goes a long way, so we are calling on plumbers and anyone else working with dye to make sure they follow the manufacturer’s instructions.”

If you see bright coloured dye or other contaminants entering a stormwater drain or waterway, take a photo and call EPA’s 24-hour hotline on 1300 372 842 or provide details online at epa.vic.gov.au/report-pollution/reporting-pollution.