I talked to some of the guys a few years back then they did mine and the toughest part is that they have to ohysically go into every single house in the city. In my house I had a finished basement so I had to cut a big chunk of sheet rock so theu could access the pipe. If I didn't have the tools or was some little old lady that process could have been a lot longer as contractors were called or the bge guys had to deal with it. They were telling me about basements they went in where they had to climb over decades of piled up junk just to find the pipes.

This isn't just digging up the street to change pipes it's connecting a pipe to every single house in the city with new meters new connections and all the issues of getting to the pipes in the first place.