Skip to main content
U.S. flag

An official website of the United States government

Here’s how you know

Dot gov

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

HTTPS

Secure .gov websites use HTTPS
A lock (LockA locked padlock) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

    • Environmental Topics
    • Air
    • Bed Bugs
    • Cancer
    • Chemicals, Toxics, and Pesticide
    • Emergency Response
    • Environmental Information by Location
    • Health
    • Land, Waste, and Cleanup
    • Lead
    • Mold
    • Radon
    • Research
    • Science Topics
    • Water Topics
    • A-Z Topic Index
    • Laws & Regulations
    • By Business Sector
    • By Topic
    • Compliance
    • Enforcement
    • Laws and Executive Orders
    • Regulations
    • Report a Violation
    • Environmental Violations
    • Fraud, Waste or Abuse
    • About EPA
    • Our Mission and What We Do
    • Headquarters Offices
    • Regional Offices
    • Labs and Research Centers
    • Planning, Budget, and Results
    • Organization Chart
    • EPA History

Breadcrumb

  1. Home
  2. Report on the Environment
  3. Water

Drinking Water

Indicators
  • Drinking Water
Related Links
  • Protect Sources of Drinking Water
  • Ground Water and Drinking Water
  • Water Topics

What are the trends in the quality of drinking water and their effects on human health?

  • Importance of Drinking Water
  • Drinking Water Quality
  • Effects on Human Health
  • ROE Indicators

Importance of Drinking Water

The average American consumes 1 to 2 liters of drinking water per day. Virtually all drinking water in the United States comes from fresh surface waters and ground water aquifers.


Drinking Water Quality

Surface waters and aquifers can be contaminated by various chemicals, microbes, and radionuclides. Disinfection of drinking water has dramatically reduced the prevalence of waterborne diseases (such as typhoid, cholera, and hepatitis) in the United States. Other processes may also be used to treat drinking water depending on the characteristics of and contaminants in the source water.

Common sources of drinking water contaminants include:

  • Industry and agriculture. Organic solvents, petroleum products, and heavy metals from disposal sites or storage facilities can migrate into aquifers. Pesticides and fertilizers can be carried into lakes and streams by rainfall runoff or snowmelt, or can percolate into aquifers.
  • Human and animal waste. Human wastes from sewage and septic systems can carry harmful microbes into drinking water sources, as can wastes from animal feedlots and wildlife. Major contaminants include Giardia, Cryptosporidium, and E. coli.
  • Treatment and distribution. While treatment can remove many contaminants, it can also leave behind byproducts (such as trihalomethanes) that may themselves be harmful. Water can also become contaminated after it enters the distribution system, from a breach in the piping system or from corrosion of plumbing materials made from lead or copper.
  • Natural sources. Some ground water is unsuitable for drinking because the local underground conditions include high levels of certain contaminants. For example, as ground water travels through rock and soil, it can pick up naturally occurring arsenic, other heavy metals, or radionuclides.

Effects on Human Health

If drinking water contains unsafe levels of contaminants, it can cause health effects, such as gastrointestinal illnesses, nervous system or reproductive effects, and chronic diseases such as cancer. Factors that can influence whether a contaminant will lead to health effects include the type of contaminant, its concentration in the water, individual susceptibility, the amount of water consumed, and the duration of exposure.

  • Health effects of chemical exposure. Chemical exposure through drinking water can lead to a variety of short- and long-term health effects. Exposure to high doses of chemicals can lead to skin discoloration or more severe problems such as nervous system or organ damage and developmental or reproductive effects. Exposure to lower doses over long periods of time can lead to chronic, longer-term conditions such as cancer. The effects of some drinking water contaminants are not yet well understood.
  • Health effects of consuming water with disease-causing microbes. Most life-threatening waterborne diseases caused by microbes (such as typhoid fever or cholera) are rare in the United States today. The more common illnesses caused by viruses, bacteria, and parasites can result in stomach pain, vomiting, diarrhea, headache, fever, and kidney failure. Infectious diseases such as hepatitis can also occur. Hepatitis may be severe in people with weakened immune systems (e.g., infants and the elderly) and sometimes fatal in people with severely compromised immune systems (e.g., cancer and AIDS patients).

ROE Indicators

The ROE presents one Drinking Water indicator based on violations of drinking water standards that states report to EPA. This indicator covers community water systems, which served 95 percent of the U.S. population in 2021.

The ROE does not provide information about the quality of drinking water from private wells, which the federal government does not monitor. It also does not discuss the quality of bottled water, which is regulated separately by the Food and Drug Administration.

The ROE does not yet include any indicators related to the connection between drinking water and health. Although contaminated drinking water can lead to waterborne diseases, these illnesses are often under-reported and the route of exposure cannot always be determined.

Report on the Environment

  • About the ROE
  • Guide to the ROE
  • Air
    • Outdoor Air Quality
    • Greenhouse Gases
    • Indoor Air Quality
  • Water
    • Fresh Surface Waters
    • Ground Water
    • Wetlands
    • Coastal Waters
    • Drinking Water
    • Recreational Waters
    • Consumable Fish and Shellfish
  • Land
    • Land Cover
    • Land Use
    • Chemicals Used on Land
    • Wastes
    • Contaminated Land
  • Human Exposure and Health
    • Exposure to Environmental Contaminants
    • Health Status
    • Disease and Conditions
  • Ecological Condition
    • Extent and Distribution
    • Diversity and Biological Balance
    • Ecological Processes
    • Physical and Chemical Attributes
    • Ecological Exposure to Contaminants
  • Explore ROE Indicators
  • Advanced Search
  • Frequent Questions
  • Publications and Activities
  • History of the ROE
  • Sustainability and the ROE
  • What You Can Do
  • Glossary
Contact Us About the Report on the Environment
Contact Us to ask a question, provide feedback, or report a problem.
Last updated on July 8, 2024
  • Assistance
  • Spanish
  • Arabic
  • Chinese (simplified)
  • Chinese (traditional)
  • French
  • Haitian Creole
  • Korean
  • Portuguese
  • Russian
  • Tagalog
  • Vietnamese
United States Environmental Protection Agency

Discover.

  • Accessibility Statement
  • Budget & Performance
  • Contracting
  • EPA www Web Snapshot
  • Grants
  • No FEAR Act Data
  • Plain Writing
  • Privacy
  • Privacy and Security Notice

Connect.

  • Data
  • Inspector General
  • Jobs
  • Newsroom
  • Regulations.gov
  • Subscribe
  • USA.gov
  • White House

Ask.

  • Contact EPA
  • EPA Disclaimers
  • Hotlines
  • FOIA Requests
  • Frequent Questions
  • Site Feedback

Follow.