Contact Water Pollution Control at (216) 664-2513 for an inspection of the City's sewer system. The inspection may determine whether a problem exists in the main sewer or on your property. If the issue is found on your property, repair will be your responsibility.
Notifying WPC prior to contacting a licensed and bonded plumber may save you unnecessary expenses. However, if you contact a licensed and bonded plumber first, make sure you get a detailed receipt.