Yes, NYC has an identical problem: most of those pipes were not documented or the documentation is lost. They're there, they know they are, they just don't know where.
Friend said the contractor called the city, who then accused him of working without a permit. And then after that was squared told him the pipe was abandoned. The contractor said okay I'm going to cut into it with a chainsaw. At which point they sent out an inspector and all hell broke loose.
City's maps showed the pipe running in the middle of the street. But it was under a row of 12 houses.
I find that hilarious. It's like they immediately assume fault, because they get used to having everything so perfectly documented, except the old technical documentation can be very imprecise. Heard stories like these, too.
Yeah, you'll find lots of surprising stuff if you care to look. For instance, when I took NASSCO certification I was exposed to the sewers that are made of brick in San Antonio. Pipes made of redwood are new to me but not that surprising.
Secondarily, don't be too suspect of the city not knowing where in-ground infrastructure is. This business is tricky. You have to take calibrated GPS land markers out (that are hopefully properly calibrated) and document things like depth. Often it's contractors doing it rather than the actual city workers, and they're usually paid on a per inspection basis (but this can vary). Much of this was drawn on really huge maps that went into equally huge books back in the day, now of course ESRI is used for everything but much of that was lift and shift in most cities that I'm aware of, so data should be trusted but verified.