Earlier quoted context omitted.
Woah. The water mains are 800 feet down? How does that work? How did they even get there?
I'm guessing they probably got there before everything on top was built, but how do they get down there now for repairs and such?
"[New York City Water Tunnel No. 3] was authorized in 1954. A third tunnel was needed so tunnel one and tunnel two could be closed for repairs. Stage One was begun in 1970 and completed in 1993 and put into service in 1998."[1]
This seems to imply that the later stages of the old two tunnels have never seen repairs.
[1] https://en.wikipedia.org/wiki/New_York_City_Water_Tunnel_No....