Ownership and responsibility for sewer repair varies widely between different municipalities. In our city the homeowner is responsible for the sewer pipe up to the city easement (which extends from the street into the lot). In other nearby cities the homeowners responsibility can be as little as the edge of the house foundation to as far as the tie-in at the sewer line in the street. In some places the rules are quite complex with the result that one homeowner gets his sewer pipe cleaned out (or repaired when necessary) by the city and his nextdoor neighbor has to hire a company at his own expense.
Sewer repairs can be 1000s even if they only involve digging up the front lawn. This quickly becomes 10s of thousands if the sewer repair includes digging up concrete drive ways, sidewalks and city streets. It can become astronomical when the city determines that the homeowner should have been aware of a long standing sewer problem and didn't fix it (with the result of extensive soil contamination). -- Got some spare cpu cycles ? Join Team Helix or Team Starfire!
In some places the rules are quite complex with the result that one homeowner gets his sewer pipe cleaned out (or repaired when necessary) by the city
I've never heard of such thing. Not that it can't happen, but according to my experience cities' responsibility is usually restricted to the main lines, or goes no further than the curb. -- Wacky Races 2012!