Long Views » Blog Archive » Cistern Circles of San Francisco
I have often wondered what the brick circles along many of the streets in San Francisco are. I had always thought they were some kind of historical marker. It turns out they represent a nice piece of long term civic planning and disaster preparedness. Each one marks a 75,000 gallon cistern that is an emergency water supply for earthquakes and fires. These were installed during the rebuilding effort after the 01906 earthquake.