Here is a little quandary for you: where does the plumbing in condemned houses go when the houses are torn down? What happens after all the rubble is hauled off and the lot has been filled in? What happens when a new home is built on that lot? Let's trace the line of pipes to their origins to answer these questions.
A Plumber Disconnects the Plumbing in the House
A plumber is hired to enter a condemned house. He or she disconnects all of the plumbing within the house and closes off the pipes underground. (Likewise, an electrician will do the same for the electricity, and a gas company agent for the gas.) Then the house is "safe" to demolish completely and the rubble carried away. As for all of the pipes and plumbing inside the house at the time of demolition, they are removed with the rubble.
The Pipes Are Now Underground
When an empty lot is filled in with dirt, the pipes that once fed into the condemned house are still there. They are now just underground, closed off, and waiting to enter an new house. The pipes leading to the city sewer are there, as well as the pipes that bring water into the new house from the city's water supply. Even though you cannot see them because they are buried, they are there.
The Plumber Connects New Pipes
When a new home is built on this same lot, the new pipes in the new house are connected. The plumber who previously disconnected the plumbing in the condemned house now has the honor of connecting the city pipes to the new pipes in the new house. This plumber also provides information to the city about the whereabouts of the underground plumbing so that the construction contractors do not accidentally excavate the plumbing or strike it open and cause flooding.
Understanding the Differences of Building on a Fresh Lot versus a Condemned Lot
It is a slightly different process for building a new house on a fresh lot versus building a new house on a formerly condemned property. Quite often, as a new house and a new lot are built, the plumbing has to be installed right after excavation and before the frame of the house is built. There are no restrictions as to where the plumbing needs to go. On a formerly condemned lot, your new home has to take into consideration where the old plumbing lies so that your house's plumbing connects properly.