I recently moved to San Francisco and decided to explore what looked like an interesting tunnel. This tunnel is going directly to the sea, it used to be a sewer but is only used as a storm drain nowadays.
I had to wait for the very low tides to get in. I'm sure there are manholes a little bit further that give an easier access, but I preferred to enter by the outfall since it brings less attention.
I didn't see many pictures of this tunnel before. I expected to see more graffitis or signs of visits, but I found none. I guess it's very inconvenient to go through the outfall access with normal tides.

Please excuse the poor picture quality. I just bought myself a better camera and a tripod for the next ones!

Cool, how far up did the tunnel go? Neat features too, any idea what the purpose of it might be?

It connects to other storm drains under the city, so it goes pretty far. I didn't stay very long inside because of the tide, and since it is is built under a high cliff there were no other manholes/exits in sight. If I was confident about other POE I would have explored further.

The tunnel was built after the 1906 earthquake, first used as a sewer but now used as a storm drain. The wall in the middle was built in the 1990s to prevent ocean water from going inside the drains.

That's pretty impressive, Minneapolis has tunnels that run sometimes 100 feet below the surface like that too, and can turn deadly if it starts to rain since you can't get out. Does SF rain frequently? Otherwise you could just time the tides and take a nice long trip between high and low if you know its likely to be safe, assuming you think the tunnel rises above sea level at high tide.

I did think about staying inside between tides, but the problem is that two consecutive low tides are not at the same height, and only the lowest one gives an easy access. So I didn't think it was worth it.

It didn't rain since March in SF, so that's not something I worry about

Have you ever thought of an inflatable raft? Or an air mattress? I've used both successfully to get in and out of drains. Rafts are fun

I did too, but I am worried about the rip currents in this area, and several rocks that can damage the raft.

Anyway, I'm sure there are other tunnels with easier access in SF. In fact when I explored this tunnel, I met another group of explorers who told me about another one in the south. And I'm still trying to find the locations described in this article, these ones should be fun to explore too: www.thebolditalic....nder-san-francisco

Posted by romainpp Anyway, I'm sure there are other tunnels with easier access in SF. In fact when I explored this tunnel, I met another group of explorers who told me about another one in the south. And I'm still trying to find the locations described in this article, these ones should be fun to explore too: www.thebolditalic....nder-san-francisco

The tunnels in the article that have the most graffiti in them are no longer accessible, at least last time I checked

Posted by always_exploring The tunnels in the article that have the most graffiti in them are no longer accessible, at least last time I checked

Bummer... I was wondering if this tunnel was a storm drain or a sewer, or something else entirely. I guess it doesn't matter anymore.

Ooooh I think I know what that tunnel is (thanks Google)! It's probably the same the other explorers I have met told me about.
If it is indeed no longer accessible where you think, I would not underestimate the fact that it reaches the surface after half a mile. Or maybe I'm confusing with the other tunnel running parallel, to be verified.

Posted by shotgun mario Have you ever thought of an inflatable raft? Or an air mattress? I've used both successfully to get in and out of drains. Rafts are fun

Floating out of a tunnel on a mattress is a pretty bad ass way to make an exit.

partime wanderer posted some neat tunnels a while back. they were way, way, south of san francisco though.

Posted by RescueMe1060 partime wanderer posted some neat tunnels a while back. they were way, way, south of san francisco though.

That doesn't surprise me. From my understanding the vast majority of storm drains in the city are combined with the sewers, which makes them not fun to explore. But there is no such combined system once you go south.

Posted by Flashyfashionfraud Floating out of a tunnel on a mattress is a pretty bad ass way to make an exit.

I took photos when everyone went on it. We pulled each other in and out on a spool of balloon ribbon, and floated into the outfall with a 2x4 as a paddle.

Posted by romainpp That doesn't surprise me. From my understanding the vast majority of storm drains in the city are combined with the sewers, which makes them not fun to explore. But there is no such combined system once you go south.

That's correct, walk down any street in the Mission district and you'll be able to smell the honey.

Posted by romainpp Ooooh I think I know what that tunnel is (thanks Google)! It's probably the same the other explorers I have met told me about. If it is indeed no longer accessible where you think, I would not underestimate the fact that it reaches the surface after half a mile. Or maybe I'm confusing with the other tunnel running parallel, to be verified.

I'm pretty sure we're talking about the same set of tunnels,and I believe it is the tunnel that is north of the first one that has a ton of graffiti. Sadly I don't think that one reaches the surface at all but I could def be wrong, if you check it out and find a way in, update this thread!

Posted by always_exploring I'm pretty sure we're talking about the same set of tunnels,and I believe it is the tunnel that is north of the first one that has a ton of graffiti. Sadly I don't think that one reaches the surface at all but I could def be wrong, if you check it out and find a way in, update this thread!

I'm assuming this image from The Bold Italic blog post is from the same tunnel.



The good news is if my assumption is right, then there is a way in!
The bad news is if my assumption is right, then this manhole is in the middle of a road. But heck, difficult doesn't mean impossible!

Oh and I just found this other recent article from The Bold Italic. They have some really cool shots of the same tunnel I have been to!

http://www.thebold...nder-san-francisco

1. (from The Bold Italic)


2. (from The Bold Italic)


3. (from The Bold Italic)