Last weekend we had a minor sewer backup, but we snaked it out via the clean-out port on the sidewalk and things seemed to be going ok. But on Friday afternoon, things were going very much not ok. Nearly complete blockage, which means almost no drainage from anything on the "Main Room" side of the building: no bathrooms! No amount of snaking made a difference. Panic and horror.
Our theory was that the connection between our main drain and the sewer had finally failed, as our various plumbers have been giving that the side-eye for several years now. It was looking very much like "time to jackhammer the sidewalk". We called the City, who wouldn't commit to a date more firm than "maybe Monday".
So... we rented four porta-potties and a handwash station. Inside Lands! All of the grossness of attending a festival without having to be around trees!
The city folks did show up on Friday evening, though, and told us that the part of the pipe that had turned to dust was on our side of the junction, not theirs, and so -- congratulations -- it was our problem, have a nice night.
This is beyond the scope of what your average plumber is prepared for, and also, this is a "call before you dig" situation, since the street is riddled with gas lines, so even once we find a plumber-slash-demolitions-expert who can do the work, they can't do anything until a different city crew shows up and spraypaints things with "cut here, not there".
Fortunately the DNA Pizza building is on a different drain system, due to them originally being separate properties, so the restaurant and Above DNA restrooms still work. But that's only 4 toilets for the whole building, so that's not ideal. But unsurprisingly, many people were happier waiting in line there than using the porta-potties.
I'd recommend you switch from beer to shots, you'll have to pee less. And never drink water. Fish fuck in it.
I think this photo from 2000 shows the inside portion of the "lateral" that connects us to the sewer. It's the deeper one.
You will be excited to learn that there is an interactive map of the San Francisco Sewer Collection System which looks exactly like the sort of thing you'd see on a heist show, where the hacker in the van pulls this up and dramatically intones, "I'M IN". What they never say, though, is, "Give me a minute, the site is kind of slow, SFPUC doesn't have much of an IT budget." But from this map we can see that the DNA Lounge drain is "Lateral Service Connection L-157660, 6" diameter" (Pizza being L-157390), and the destination is "Eleventh Street Main Sewer P-98524, 36" diameter". It feeds south to "Harrison Street Main Sewer P-76719, 7' diameter", installed 1911.
The map says that the DNA lateral was installed in 1998 and the sewer in 1997, but that cannot be true. I'm reasonably certain that they were not digging up the sidewalk here in 1998. We didn't do our plumbing excavation until 2000, and that all stayed inside the building: we did not open the sidewalk. So that's a bit of a mystery.
The Eleventh Street Main Sewer feeds into the Mission & Fourth Street Tunnel P-98155, 8', installed in 1972, and thence to the "Transport / Storage Boxes" under The Embarcadero. These are vast, 35' tall, miles long cisterns (photos here!) that serve as buffers in case of high flow from rainfall, and in storms will let the sewers vent directly into the Bay (after "slight decantment") instead of backing up into your kitchen. This is necessary because San Francisco has a single system instead of separate sewers and storm drains, as in most other cities. As far as I can tell, the reason for that is "it seemed like a good idea during the Barbary Coast days, and it would cost billions to change now, so yolo."
The arrows on the interactive map aren't very clear on this next part, but my understanding from the SFPUC site is that the next step of the journey depends on whether it's raining. Normally everything flows from the Transport / Storage Boxes to the Southeast Treatment Plant which vents into the Bay ("Outfall") via Islais Creek, but sometimes it is also allowed to flow to the North Point Wet Weather Treatment Facility, which vents along Piers 33 and 35.
(Points West instead use the Oceanside Facility near Lake Merced. SF has two "sewersheds" that divide the city roughly in half vertically, which is why there are only two graphs on the COVID-19 Wastewater Surveillance Network.)
I'm not sure when the (extremely scenic) Mission Creek Channel Pump Station comes into play.
Anyway, let this be a lesson to you: the movies have lied to you. Only the Harrison Street sewer widens enough for a dirtbike, and even then only barely. Most of these sewers could not fit an alligator of any distinction. It's the Transport / Storage Boxes where the real action is.
For a detailed description of the SF sewer system, including its history going back to 1899, check out the San Francisco Sewer System Master Plan, 2010. I also enjoyed skimming SFPUC's Sewer System Emergency Response Plan. It's full of flowcharts and checklists, worksheets for computing overflow volume, and pictures of their awesomely-named drill bits: "Select appropriate nozzle for breaking a stoppage. This would be either a Pipe Wolf (6"-15"), Tadpole/Polywog with penetrator (18"-24"), Warthog or Bulldog with penetrator." (And if you're into that kind of thing, you may also enjoy the FDNY Forcible Entry Reference Guide, or "Care and Feeding of your Halligan Tool".)
I love this stuff because we are extremely focused on checklists to keep this place running, and it's fun to see how other organizations do it. The title of the DNA Lounge employee handbook is literally "Checklists Get Shit Done". 72 point type, right on the cover.
In conclusion: I have no idea how expensive this shit is going to be, so please contribute to our Patreon, AKA the DNA Lounge Adopt-a-Sewer program.