Around these parts civic historian Paul Rosenberg is greatly missed. Dove tailing on Paul’s September 2015 posting - here is a 2022 presentation by Joel Pomerantz about water beneath city neighborhoods given to the San Francisco History Association.
Thirsty in Early San Francisco: A Very Localized Search for Water - SFHS Program with Joel Pomerantz
https://www.youtube.com/watch?v=LB33_Ox6akQ