When I sat down to write this blog, the title was “What makes water drinkable?”  That is still on the agenda, but it seems best to first explain what public health is, how we got to regulations and guidelines, and what the difference between the two is.  Note that regulations and guidelines for drinking water is a global topic, but the focus here is for the US.

Let your mind drift back to the Industrial Revolution.  In the 1800s, people moved into cities that were not prepared for the sudden increase in population.  Most domestic water supplies were centralized community hand-pumps that were inadequate.  In some cases they were nonexistent.  Waste-disposal systems like we are familiar with today did not exist at all.  Unhygienic conditions were rampant and there were repeated epidemics of water-related diseases like cholera, yellow fever, typhoid fever, and diarrhea (remember that blog?). 

There was a growing awareness of water-related diseases and the recognition that chlorination of public water supplies could reduce these diseases to benefit the public’s health.  In 1908, Jersey City, New Jersey was the first city in the US to begin chlorinating water supplies.  Thousands of communities across the US followed suit.  The concept of “public health” caught on. 

By 1900, 40 states had health departments.  In 1902, the United States Public Health Service (USPHS) was authorized by Congress to research diseases, water supplies, and sanitation.  From the 1930s through the 1950s, state and local health departments conducted public education that emphasized disease prevention, water treatment, food safety, sewage and solid waste disposal, and handwashing.  Water-related diseases dropped substantially, as shown in the chart below

Graph showing the death rate for infectious diseases, per 100,000 population - United States, 1900-1996. In 1900, the death rate was 800 per 1000 people and 40 states have health departments. Around 1915, the first continuous use of chlorine in water in the United States Occurred, and in 1917 the Spanish Influenza pandemic struck the world. In the early 1920s, the last human-to-human transmission of plague occurred. After 1940, penicillin was first administered. In the 1950s, the Salk vaccine was first given. In the 1960s, Congress passed the Vaccination Assistance Act.
From Centers for Disease Control (CDC): “History of Drinking Water.”

Problems with poor operating procedures, inadequate facilities, and inconsistent management of public water supplies persisted.  So, Congress passed the Safe Drinking Water Act in 1974.  This act gave the recently-established US Environmental Protection Agency (EPA) authority to set standards for public drinking water supplies in the US.  There are 151,000 public systems providing drinking water to Americans.  The 13% US households served by private wells are not subject to EPA regulations for microbiologic, chemical, and other contaminants in drinking water.  A regulation is required for legal operation, whereas a guideline is more like a statement.  

Today, there are regulations for over 90 contaminants in public drinking water supplies.  Find out more about them here.