About 100 environmentalists were out Saturday to protest York region's new sewage system project.

York is planning to expand an existing sewer pipe into the Pickering region and into Lake Ontario. Environmentalists say the plan has been poorly thought out.

The large group of protesters wanted to make themselves heard before the project was presented to the Ontario government for approval. They are saying a larger pipe could potentially leak a stench on people who live in the area as it will transfer about a billion litres of raw sewage through Pickering communities on a daily basis.

"I worry bout the sewage line coming underneath the aquifers and leaking into our drinking water," said Pickering resident Sue Zuro.

The protest took place at Bob Hunter Memorial Park - a green space named after the co-founder of environmental organization Greenpeace. York's sewage plan includes running a pipe right through the park.

"I think that's an insult to the memory of my husband that such a thing would even be thought of," said Bobbi Hunter, the environmentalist's widow.

The website for the pipe expansion project says that the new sewage system is "critical to ensuring adequate wastewater treatment" for the region's growing population.

York region's current population is currently 910,000 but is expected to grow to more than 1.5 million by 2031.

"York region shouldn't be using our lake, which we get our drinking water from, for its toilet," said activist Jim Robb. "If York region wants to grow, it should be treating its sewage within their region."