Some nonconforming sewer connections are private sewer lines that extend beyond the property boundary into the public right-of-way to connect with the public sewer. Most of these private lines were never recorded so they can't be marked for location before any utility construction in the right-of-way.*
It's not uncommon for property owners to be unaware that a private sewer line in the public right-of-way connects their property to the public sewer. The best way to know for sure is to hire a plumber to scope your private sewer lateral. The cost usually ranges from $100 to $200. The plumber should provide you with a recording of the scope on DVD*.
Under certain conditions, the city may accept or adopt a private line in the right-of-way serving residential properties.
*Inability to mark a private sewer line in the public right-of-way can make the owner of the line liable for construction delays and equipment damage.
*DVD copies cannot be returned.