From SFBC:
The Sewer Ride returns! Join this above-ground, member-led biking tour of the San Francisco sewer system. Local historians and storm water enthusiasts will take us back in time, help us understand our watershed, and immerse us in sewer history. Find out what happens when we flush! Focus will be on the Mission District and Mission Creek.
SF Bicycle Coalition recreational rides are free for SFBC members (a $5 donation from non-members is appreciated); rain cancels rides. Questions? Email miles@milesepstein.com