Visitors to Paris, especially those from parts of the world where droughts are common like the Southwestern United States, are often shocked and concerned to see water gushing down the gutters of Paris when it hasn’t been raining. Don’t worry, it’s not drinking water. In fact, it’s quite environmentally friendly!
Back in the late 19th century, when Emperor Napoléon III’s city planner Baron Haussmann was completely renovating the streets of Paris, he integrated two public water systems into the underground pipes and sewers: one was treated, potable drinking water that flows through our taps, the other untreated, non-potable water from the Canal St-Martin and the Seine that is used to clean the streets.
Unique to France, it’s an ingenious system that has been working for well over a century. A sanitation worker in a fluorescent green suit uses a tool to turn on the water, directing the stream down the street with a rolled up piece of carpet if needed, then follows the stream with a plastic broom sweeping in debris from the sidewalks and between car tires until he reaches the sewer grate.
Anything too big to go into the grate is scooped up into a trash bin and carted away. The same untreated water is used by the little green vehicles with the pressure sprayers cleaning the larger sidewalks and squares, especially after the open-air markets close or a festival, parade, or protest march passes through.
You can read an in-depth article about the history of this system (and many other uniquely Parisian oddities) in the excellent Parisian Fields blog by Norman Ball, a retired university professor, and Philippa Campsie, a Canadian writer.