16. Many Londoners believed the Thames was tidal and so would carry their waste away; they were wrong
That Londoners could throw their filth into the River Thames in the morning and then draw bathing and drinking water from the same river in the evening may seem shocking to us. However, it’s worth remembering that even in the 19th century, many of the city’s residents lacked a proper understanding of their biggest river. Many people, and above all, the uneducated masses, believed that their waste would just wash away with the river. However, since the Thames is a tidal river in London, the reality was quite different.
The Thames ebbed and flowed. At high tide, the high water kept the sewage pushed up the drains and sewage. So, when people went to the river to take advantage of the high level and draw water from it, they may not see waste floating in it. When the tide was low, however, the waste would pour out of the sewers and drains. At that time of the day, it would have been impossible not to notice the filth, with animal carcasses and human bodies sometimes visible from London’s famous bridges.