Umm, you may not like to find this out, but there are places where the NYC water supply mains are within 3 feet of the surface. Not all of the line is deep rock tunnel.

Net daily consumption on the NYC water supply in whole is somewhere just over 1.1 billion gallons per day. One of the deep rock mains is leaking over 1.1 million gallons per day. The good news is the source will never dry up or run out.

When I found out about the shallow lines and their location, I was quite alarmed. The supply still remains quite vulnerable to terrorist activity, should any of them become smart enough to capitalize on such knowledge.