What Is the Safe Drinking Water Act?

Medically Reviewed by Dany Paul Baby, MD on April 08, 2022

The Safe Drinking Water Act (SDWA) is a part of the Public Health Service Act that was enacted in the USA. It is the primary federal law in the country when it comes to regulating public water and protecting citizens from harmful contaminants. 

The law was first established in 1974 and later amended in 1986, 1996, and 2018.

The Environmental Protection Agency (EPA) enforces the SDWA by setting standards and requirements for the quality of drinking water. These standards focus on different contaminants in the water that cause illness and disease.

What Does the Safe Drinking Water Act Do?

The Safe Drinking Water Act encompasses the quality of all water used for drinking purposes. This includes water from underground sources as well as aboveground sources. 

Here is a Safe Drinking Water Act summary:

  • The Act permits the EPA to set standards for tap water protection and requires all public water system owners and operators to follow these regulations.
  • In 1996, the amendments made to SDWA authorized the EPA to include a detailed cost and risk assessment when establishing the standards. The institution should also consider peer-reviewed science when doing so.
  • The state governments agreed to impose the EPA standards and to encourage the implementation of secondary regulations as needed.
  • The EPA also sets minimum standards for state governments' programs to ensure the protection of underground sources of drinking water from the infusion of harmful fluids.

What Are EPA Drinking Water Standards?

The EPA established the following standards for drinking water safety: 

The Safe Drinking Water Act (SDWA)

Congress passed the Safe Drinking Water Act (SDWA) in 1974 to protect the public drinking water. Under the Act, the EPA laid down clear standards for the quality of drinking water and regulates states, local institutions, and water suppliers.

The EPA also sets maximum contaminant levels and treatment requirements for public drinking water

The standards for contaminants include:

  • Contaminant Candidate List (CCL). This obliges the EPA to list unregulated contaminants that have been found or may occur in public water. This list is published every five years.
  • Regulatory determination for the CCL. This requires the EPA to regulate a minimum of 5 CCL contaminants with the SDWA standard every five years. It also establishes three criteria, including health impacts, presence in public water systems, and good opportunities to reduce potential health risks.
  • Unregulated contaminant monitoring. This requires the EPA to set criteria for a program to regulate a minimum of 30 unregulated contaminants after every five years.
  • Regulation development. When the EPA decides to monitor a contaminant through regulatory determination, it is assigned 24 months from the period of determination to develop a regulation. The EPA also gets 18 months from the point of development to finalize the rule. The SDWA requires the EPA to evaluate several factors when setting regulations.
  • Six-year review. The EPA has to provide a six-year review for every standard and revise it if necessary. Per the act, the revision should focus on improving public health protection.
  • National Contaminant Occurrence Database (NCOD). The EPA has to maintain and organize a database for public drinking water contaminant occurrence. The agency then uses this information about regulated and unregulated contaminants in public water systems.

National Primary Drinking Water Regulations (NPDWR)

National Primary Drinking Water Regulations (NPDWR) are established techniques and standards that national water systems must follow. These standards limit contaminant levels in the drinking water to protect public health.

The NPDWR involves standards for:

  • Disinfectants
  • Microorganisms
  • Inorganic Chemicals
  • Organic Chemicals
  • Disinfection Byproducts
  • Radionuclides

National Secondary Drinking Water Regulations (NSDWR)

NSDWR are regulations for public water systems used to manage the quality aspects of the drinking water unrelated to health. These secondary standards regulate contaminants that cause cosmetic impacts, such as skin discoloration, and aesthetic effects, such as the taste, smell, and color of the water. 

The EPA suggests that public water systems follow these standards but does not require them to do so. These are originally non-enforceable rules, but many states can choose to make them enforceable.

The listed contaminants may not ordinarily be harmful to human health, but they can be in higher amounts. If the contaminant level is above the standard, the water looks cloudy or smells and tastes bad.

The EPA needs to take special notice, meanwhile, when the fluoride secondary standard exceeds 2.0 mg/L. Public water systems that exceed this standard but stay within the fluoride's primary standard of 4.0 mg/L have to give public notice to persons affected. This notice should not be served later than a year after the water system identifies the fluoride exceedance in drinking water.

The 15 contaminants included in NSDWR for drinking water safety are:


Secondary Standard


0.05 to 0.2 mg/L


1.0 mg/L


15 (color units)


250 mg/L




2.0 mg/L

Foaming Agents 

0.5 mg/L


3 threshold odor number


0.05 mg/L


0.3 mg/L




0.10 mg/L


5 mg/L


250 mg/L

Total Dissolved Solids

500 mg/L


Bottled Water Regulations

The SDWA doesn't enforce the protection of bottled water. The U.S Food and Drug Administration (FDA) regulates bottled drinking water.

Consumer Confidence Reports (CRR)

The public water systems or community water suppliers operating in the country are required to provide a report annually to their consumers. This report is known as a Consumer Confidence Report (CCR).

This report aims to enlighten the consumers about the quality of the drinking water, its sources, and the contaminants that water contains. The CRR also teaches consumers how to ensure drinking water safety on their own.

What Does the Office of Ground Water and Drinking Water (OGWDW) Do?

The OGWDW oversees the implementation of the Safe Drinking Water Act from the accountable entities. This institution works with states, tribes, and other partners to protect human health by assuring groundwater quality standards.

The OGWDW performs the following tasks:

  • Development of the national drinking water standards
  • Aiding implementation of the drinking water standards
  • Monitoring the funds provided to the state programs related to drinking water safety
  • Strengthening smaller public drinking water systems
  • Implementing the Underground Injection Control Program to protect underground drinking water sources
  • Guiding the public about the quality of the drinking water available

Show Sources


Centers for Disease Control and Prevention (CDC): "Drinking Water Standards and Regulations."

Congressional Research Service: "Safe Drinking Water Act (SDWA): A Summary of the Act and Its Major Requirements."

United States Environmental Protection Agency (EPA): "About the Office of Water," "Drinking Water Regulations and Contaminants," "Drinking Water Contaminant Candidate List (CCL) and Regulatory Determination," "Monitoring Unregulated Contaminants in Drinking Water," "National Primary Drinking Water Regulations," "SDWA Evaluation and Rulemaking Process," "Summary of the Safe Drinking Water Act." 

U.S. Food and Drug Administration: "FDA Regulates the Safety of Bottled Water Beverages Including Flavored Water and Nutrient-Added Water Beverages."

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