What prompted health departments to create regulations for public swimming pools in the mid-20th century?

The regulation of public swimming pools by health departments in the mid-20th century was significantly influenced by the fear of polio. During this period, polio was a highly contagious viral disease that primarily affected children and could lead to severe complications, including paralysis. Concerns about the spread of polio in communal settings, such as swimming pools, prompted health authorities to take action to protect public health.

As the disease spread through contaminated water and surfaces, the establishment of regulations focused on ensuring the cleanliness and safety of swimming facilities became essential. These regulations aimed to limit the potential transmission of polio and other waterborne illnesses by mandating proper sanitation, water treatment, and operational standards for public pools. Thus, the fear of polio served as a catalyst for implementing public health measures that were vital for ensuring the safety of recreational water activities.