Public water system

Public water system is a regulatory term used in the United States and Canada, referring to certain utilities and organizations providing drinking water.
United States.
The US Safe Drinking Water Act and derivative legislation define "public water system" as an entity that provides "water for human consumption through pipes or other constructed conveyances to at least 15 service connections or serves an average of at least 25 people for at least 60 days a year." The term "public" in "public water system" refers to the people drinking the water, not to the ownership of the system.
Some US states (e.g. New York) have varying definitions.
Over 286 million Americans get their tap water from a community water system. Eight percent of the community water systems—large municipal water systems—provide water to 82 percent of the US population.
Subcategorization.
The United States Environmental Protection Agency (EPA) has defined three types of public water systems:
There are over 150,000 public water systems.
EPA also classifies water systems according to the number of people they serve:
Water systems may be categorized by their source of water:
Water-related diseases and contaminants in public water systems.
Sources of drinking water are subject to contamination and require appropriate treatment to remove disease-causing contaminants. Contamination of drinking water supplies can occur in the source water as well as in the distribution system after water treatment has already occurred. There are many sources of water contamination, including naturally occurring chemicals and minerals (for example, arsenic, radon, uranium), local land use practices (application of fertilizers and pesticides; concentrated animal feeding operations), manufacturing processes, and sewer overflows or wastewater releases.
The presence of contaminants in water can lead to adverse health effects, including gastrointestinal illness, reproductive problems, and neurological disorders. Infants, young children, pregnant women, the elderly, and people whose immune systems are compromised because of AIDS, chemotherapy, or transplant medications, may be especially susceptible to illness from some contaminants.
The US Centers for Disease Control and Prevention publishes a list of the leading causes of waterborne outbreaks in public water systems.
Canada.
The Canadian provinces of Manitoba and Nova Scotia also use this definition.