Hidden Heroes: The Secret Cisterns Beneath San Francisco’s Streets
Have you ever noticed those circles of bricks in the middle of intersections around San Francisco? I couldn’t resist diving into their story, and here’s what I found: they’re markers for SF’s 180+ underground water cisterns—a genius emergency firefighting tool dating back to the 1850s! These reservoirs, holding 75,000 to 200,000 gallons each, were born out of necessity after devastating fires between 1849 and 1851 ravaged the city. Though they fell into disrepair with the rise of water mains and hydrants, the catastrophic 1906 earthquake proved just how essential they were when broken water mains left the city helpless against raging fires. The good news? Today’s cisterns have been rebuilt with concrete and steel, ready to support firefighters when needed. Want to know where they all are? SFFD has a map just waiting for your curiosity!
*Insight gathered from Amusing Planet
