Saskatchewan Environment is investigating after forty to fifty thousand cubic meters of raw sewage spilled into the the South Saskatchewan River Back on July 19.

The City of Saskatoon's Mark Keller says heavy rains overloaded to system, sending the overflowing water into the river.

However, Keller says new procedures are in place to ensure it doesn't happen again.

"In order to mitigate some of those concerns for the future, we've improved our emergency response procedure with utilization of staff for standby notification, and put in place some added equipment to be able to respond to the incident in as quick a way as possible," Keller said.

Keller says it was rain water that went through the sewer system, and says it was pretty diluted.