Is Paris the only city where the sewers are an attraction where one can go on organized tours?
Vienna.
London.
I had an amzing plan for a friend’s bachelor party: dress him up like a mutant ninja turtle and emerge from manholes close to bars on the route… but we never did that, sadly.
With enough willpower, you could probably tour the sewers in any city?
Hell, people make a living of that. Probably the worst job in the world though.
Sydney. The historic Tank Stream - the town’s original water source and later an open drain, then covered over as a sewer, storm water and sewerage channel - is intermittently available for tours.
Try Naples. And the Cloaca Maxima in Rome is also worth mentioning.
In Istambul you can visit the cisterns, which are underground. Don’t know whether that counts or not, but here they are.
Not since the pandemic started, though they’re hoping to resume them in May of next year. (Of course, that’s what they also said last year.)
Cleveland’s sewer tunnels are mostly too small for the public to tour through, but the sewer department has great public relations, and often has public tours of the sewage treatment facilities. They hand out flyers with the tagline “You’ve really gotta go”.
I’m not aware of tours inside London’s sewers, but you can visit the steam pumps they used to use at Crossness:
I specifically remember my grade-school class doing a guided tour of one of Indianapolis’s water-treatment plants. It was the worst field trip EVER.
Doesn’t it have something to do with the various types of sewers? Older cities had a sort of combined wastewater/stormwater system, and from what I understand had larger pipes/tunnels and were less fetid than modern separated systems.
For example, modern cities have separate storm sewers (basically drainage pipes/tunnels) and sanitary sewers (where your toilet and everything else goes). Sanitary sewer pipes aren’t as large; something like a 90" pipe (7.5 feet) is a huge one. And not that big to go walking through either.
Storm sewer pipes are a LOT larger, but probably less interesting. Except maybe large scale projects like this. Apparently back in the day(19th/early 20th century), the city just basically put a bunch of older streams/creeks into culverts and built over the top of them, and they’ve had drainage issues ever since. The idea is to have each of those ancient streams dump into this thing, and have it go over to the river, and essentially get siphoned/pushed out when enough water gets into the system.
London is nearing the end of a massive construction to cope with storm surge overflows
Sadly, it is the case that both sorts of drains go into the same tunnels, and when there’s too much rain, the (mixed) overflow currently goes into the Thames (fortunately two massive tides a day means that nothing should linger, but even so…)
There used to be a guy who led completely unofficial (and illegal) tours of the sewers here in Brooklyn. He would just pop a manhole cover, shoot down a ladder, and take a group down.
I don’t think he does it anymore (maybe he got caught?), but you can tour the wastewater treatment plant. Digester Egg Tours - DEP which is quite cool.
buildup of carbon monoxide, hydrogen sulphide, methane, & sulphur dioxide means going down to these places is not something one should do lightly.
There are now usually three distinct things being dealt with - stormwater [sharp demand to clear surface water after rain], sewerage [household water use], sewage [human waste]. The ideal geometry of their pipes differed, and was influenced by population density, anticipated demand, topography etc.
In the pre-mechanical era the emphasis was on making the system work by gravity and natural forcing, so combined systems were designed to give extra water to push faecal matter through. This also meant big pipes/ channels. With flush toilets and pumping stations that is no longer needed and the focus has gone to getting these separated so that the water in the different systems can be efficiently treated in bulk. A sewer treatment plant takes up a lot of land so you don’t want to create a system that unnecessarily multiplies the volume you need to treat.