The “Cloaca Maxima” or “Greatest Sewer,” built in 6th century BC Rome to drain marsh and rain water and later to channel waste, is still in use today.
Before modern sewer systems, many cities had toilets that simply emptied into cesspools, which themselves had to be emptied occasionally. In London, this job was legally required to be done at night by “night men” or “night soil men,” who then sold the waste to nearby farmers as fertilizer.
Human waste in the form of sewage is still used as crop fertilizer to this day, and works safely after toxins are removed.
Arguably the most ambitious project to accommodate sewage was the reversing the flow of the Chicago River, completed in 1900. Before that, the river flowed into Lake Michigan, contaminating the city’s drinking water with its own residents’ sewage and slaughterhouse waste. The reversal of the river’s flow sent these unpleasant ingredients downriver, away from the city.
Storm drains and wastewater sewers are not the same, also known as “storm sewers” and “sanitary sewers.” One is intended for rain and melting snow that can be discharged into waterways untreated, the other for human waste that should be treated. Some cities combine these waste types into a “combined system.”
Many early efforts at urban sewer systems were abandoned during the Middle Ages, with some interesting etiquette born as a result. The gentlemanly rule that the man walk on the street side of a lady down the sidewalk comes from the fact that animal dung would collect near the street and people would empty dirty chamberpots into the street from windows above, offenses that a gentleman should endure rather than his female companion.
Though wastewater treatment is more common than in times past, only about 48% is treated at all before being discharged into global waterways.