Soon after I got to the art gallery where the sewer tour started, this guy climbed up a yellow ladder and started talking to us. He explained that we would go down Lilac Lane, looking at the art and then do a tour of some of the important parts of San Francisco's water treatment system.


I should have taken pictures of the street art on Lilac Lane. Some of it is quite beautiful. Much more than just "graffiti". If you get a chance to wander down San Francisco's Lilac Lane (just to look at the art) go for it!

In the early days, there had been a creek that ran down approximately the route of Cesar Chavez St. Then as the city grew the need for a plumbing system became more apparent. Finally, about a hundred years ago, the city fathers in their infinite wisdom built underground sewer lines along creek and built up the area.

At this point he was explaining that the sewer lines that go under Cesar Chavez (the road formerly known as Army St.) are a key part of San Francisco's drainage system. If it's not working right then the water drains into the homes in the area.

The sewer system has to be big enough to drain away all of the residential gray and black water as well as all the rain. This watershed got upgraded once in the 1940s, when they went from one pipe to two. Since then there has been a lot of development, and it has resulted in more water use. Now they have opened the sewer system again to add more capacity. He urged us to look into the guts of San Francisco as we cross the bike bridge, because it's likely our only chance. Below is what I saw.



At this point we were standing across the creek from San Francisco's main water treatment plant.


This guy (I think he is director of the water treatment plant) explained that sewage treatment boils down to using the same bacteria to do the same work as happens in our bodies.

That pump does the same work the peristaltic waved do in our intestines.

That would be San Francisco's lower intestine and colon. He explained that since they have diverted all of the toxic waste so it doesn't go there, the solid waste they collect is good enough to be spread on Solano County fields as fertilizer.



These houseboats are on Mission Creek, which is sometimes known as "shit creek". They call it that because on the rare occasion when rainfall overfills the sewers with rain, raw sewage drains out of the mouth of the creek and then through this channel to the bay.


That red shed holds the pump that is overwhelmed when the creek overflows. They do some treatment, skimming off the stuff that will float, and settling out the stuff that will settle, but too much water means the rest of it has to go out to sea "as is". Overflows are rare events. It takes A LOT of rain in a short period of time for that to happen.


That green box is where the bacteria level monitoring equipment resides. They put the information it collects on the web, so that you can see how safe the water is, 24 hours a day and 365 days a year.

As long as they keep building these residential towers, the demands on the water system will continue to grow. More people means more water use, and more sewage for the treatment plant.


When water flows through this creek bed, the grasses do a good job of cleaning it. I think it just gets rainwater and dumps it to the bay in some minor inlet.


These grates ventilate the smelliest stretch of San Francisco's sewer system. There is no known way to do anything about the odor without causing bigger problems. It didn't smell that bad, but then we were probably there on a good day.

This mural represents the river that once flowed by the building it is on. Nowadays that water goes through the sewer system.

After the tour there was an art show with an "underfoot" theme. It just seemed wrong to take pictures of most of the things I saw there. The exception was this logo. The guy wearing the shirt behind it said "visit"