The property owner is responsible for all service pipes up to and including the connection to the main. Typically this includes the pipes from inside the building out to the middle of the street.

The city's sewers are designed to dispose of very specific things. Using your toilet for disposal of many modern products will often result in blockages. The drains that connect your home to the main sewer are only big enough to carry water, toilet paper and human waste - often no wider than four inches.

This is usually caused by an empty drain trap somewhere in the house that is allowing sewer odor back into the house. You should periodically pour water down every drain trap in the house. Be sure to use enough water to completely fill each trap.