Washing your car in the driveway or street could be flushing soap, grime and oils down the stormwater drain and into our waterways, warns EPA Victoria.
As warmer weather encourages people to clean the winter grime from their cars, they could inadvertently be adding to pollution in creeks and rivers.
"The soap you use to wash the car, and the dirt and oils it removes, has to go somewhere and if you're on the street or in your driveway, that's likely to be down a stormwater drain," EPA Acting CEO Mark Rossiter said.
Mr Rossiter said commercial car washes offered a responsible alternative, but advised to look around to find those that performed the best environmentally.
"Our officers have inspected car washes that failed to properly capture and treat or dispose of the wash water. Some allowed it to drain to the street, or did not dispose of it properly and the only thing we want going down our stormwater drains is rainwater.
"Spotting a good car wash is not hard. Telltale signs of bad ones include water escaping wash bays, automatic doors or equipment that doesn't work properly, foamy water trailing to the street and generally appearing run down," said Mr Rossiter.
Neil Fox, President of Australian Car Wash Association (ACWA), said operators needed to invest in the latest technology, including in recycling the water they use.
"When you drive on the roads, your car is silently picking up a range of pollutants, from heavy metals like lead, petrochemical residues and oil. When you bring your vehicle to a purpose-built car wash, these toxins are removed during the washing process and carefully collected in settling pits, where they are then disposed of in strict accordance with regulations.
"Unlike driveway washing, modern car washes are equipped with advanced water recycling systems that ensure minimal water usage and waste collection pits that stop pollutants like heavy metals and petrochemicals entering our waterways.
"The message is clear: commercial car washes are an environmentally responsible choice. They save water and prevent harmful chemicals from seeping into our waterways.
"Members of the Australian Car Wash Association are aware of the strict environmental regulations they operate under. However, we are always looking for ways to improve, and working with authorities like Environment Protection Authority is a way of achieving that."
