A lack of sanitary plumbing, the habit of digging wells next to cesspools, living in cramped quarters in crowded cities, and a lack of understanding the necessity of hygiene caused a large part of the population to be “under the weather” a good part of the time.
Alton Brown - “Good Eats” episode on water
I tell people that plumbers have saved more lives than doctors. Which is a painful admission for a doctor to make!