Regina's sewage treatment lagoons are not working properly because of a failed part, officials say. (CBC)

Residents of Regina's northwest neighbourhoods, including Mayor Pat Fiacco, are expressing concerns about smells from a nearby sewage treatment facility.

City officials say a broken piece of machinery at the waste-water treatment plant is behind the foul odours.

Normally the sewage lagoons are not so smelly.

Fiacco said Wednesday he understands how residents feel.

"I want to sit in my backyard, I want to enjoy a barbecue in my backyard, I want to sleep with my window open -- I can't right now and nor can the majority of citizens affected by this in north-west Regina," Fiacco said. "And they have a right to be upset."

According to the city, a replacement for the defective part will not be on hand until the end of September.

In the meantime, chemicals are being used to reduce the odour.