A purple liquid was seen seeping through a residential neighbourhood Sunday afternoon as city crews spent hours trying to figure out what it could be.

The liquid, believed to be a type of dye, was first seen on Duncan Mill Road, near Don Mills and Highway 401.

Residents noticed it bubbling through cracks in the roadway. Then, the liquid flowed into the sewer system and then down to the top of the Don River.

Crews don't want to take any chances and are testing the liquid to see if it is a harmful substance.