Division of Environmental and Community Health

Maine Center for Disease Control & Prevention

A Division of the Maine Department of Health and Human Services

DHHSMeCDCEnvironmental and Community HealthDrinking WaterPublic Water SystemsSDWA at 50

50 Years of the Safe Drinking Water Act



Every time we turn on the tap, we do so with a level of confidence that the water we’re about to enjoy is clean and safe.

It hasn’t always been that way; half a century ago, environmental pollution and poor management had led to contaminated drinking water supplies in many parts of the US. Happily, since then great strides have been made toward ensuring every American has access to clean drinking water. So much so, that we now consider clean water nothing less than a basic right. And in the U.S., protection of that right is enforced in part through the Safe Drinking Water Act.

The Safe Drinking Water Act (SDWA) is the federal law regulating public drinking water. Originally passed by Congress in 1974, and marking its 50th anniversary this year, SDWA was a significant step in developing drinking water standards, establishing a comprehensive regulatory framework for the nation’s drinking water supply.

“High quality water is more than the dream of the conservationists, more than a political slogan; high quality water, in the right quantity at the right place at the right time, is essential to health, recreation, and economic growth.”
Senator Edmund Muskie

“Of the Earth’s vast resources of water, only a small fraction is fresh and drinkable. A few people among the globe’s billions have been charged with the task of ensuring everyone else has a reliable source of safe water.”
J.B. Mannion

SDWA was one of several pieces of legislation to emerge from the environmental movement of the 1960s and 1970s. Complementing other work of the time, such as the establishment of the Environmental Protection Agency (EPA) in 1970 and 1972’s Clean Water Act, which protects lakes and rivers, SDWA set standards for drinking water providers, service, and quality, and in so doing created clear accountability for safe water.

Under the SDWA, the EPA has been granted the federal power to regulate publicly accessible water that is used for bathing, cooking, dishwashing, and oral hygiene. EPA drinking water regulations apply to all privately- and publicly owned “public water systems” – providers that maintain a minimum of fifteen service connections or regularly serve water to at least twenty-five people. In Maine, primary authority over the public water supply, including administration of the SWDA and EPA regulations, rests with the CDC Drinking Water Program (DWP). The DWP oversees the monitoring, treatment, storage, and distribution of public drinking water and assesses violations of the SDWA.

Protecting public health has always been the primary goal of the SDWA. And it was with the public health in mind that amendments to the SDWA in 1986 included landmark disinfection and filtration requirements for drinking water. 1996 amendments went even further, with a focus on contaminants that pose the greatest dangers to public health. In addition, the 1996 amendments introduced new protections for at-risk populations – such as children, pregnant women, and the elderly – that may be more vulnerable to health issues that arise from contaminants in drinking water.

In large part, thanks to SDWA – and other regulatory actions by the EPA (including the Total Coliform and Surface Water Treatment rules, both implemented in 1989, and 2006’s Groundwater rule) – drinking water quality in the United States has gradually but consistently improved over the last 50 years. Before the passage of SDWA, many communities did not have access to safe drinking water; many water supplies contained what would today be unacceptable levels of toxins like lead and mercury, agricultural chemicals, and various organic and microbial contaminants. Today, Americans enjoy some of the safest drinking water in the world. Even with the persistent challenge of waterborne disease outbreaks, US drinking water quality is very good.

The success of the SDWA can be measured.

  • Disease outbreaks in public water systems, despite a rise in the 1980s, have trended downward since 1971. (Reference: American Geophysical Union)
  • More contaminants are regulated. The 1975 list contained twenty-two analytes; the EPA's current list contains ninety-four, and six per- and polyfluoroalkyl substances (PFAS) were proposed for regulation in 2023.
  • EPA's compliance reports show a 39% decrease in health-based violations between 1996 (when first reported) and 2021.
  • The Sustainable Development Goals Tracker shows that the share of the U.S. population using safely managed drinking water increased from 95% in 2005 (when first tracked) to more than 97% in 2020.
  • The American Society of Civil Engineers periodically publishes a national infrastructure report card, and the drinking water grade has improved since it was first reported in 1998.

By these measures and others, SDWA has succeeded.

Still, as we move forward through the 21st century, we must continue to identify and respond to hazards that threaten our water supply and our health. Fifty years ago, the focus was primarily on basic water treatment, but public water systems face different challenges today, such as aging infrastructure, cyber-crime, securing capital financing, and source reliability and protection. These challenges can be more keenly felt by small, rural water systems that also face staffing and funding issues. In Maine, those small, rural water systems make up the vast majority of public water systems that are served by SDWA.

Updated 4/25/2024