About 40 homes on Churchill Ave. N. in Westboro are being asked to reduce their water use effective immediately.
Officials say the sanitary system is stressed and too much additional use could lead to flooded basements.
Affected residents are asked to refrain from having showers or baths, flushing the toilet, and running their dishwashers and laundry machines.
The City says there is no risk to the drinking water supply at this time.
The Dovercourt and Pinecrest Community Centres are offering showers and toilet services to residents who need them.
Affected residents are also encouraged to move items out of their basements to higher floors to prevent possible damage or loss.