Who Protects Air and Water: The EPA, the States, and the Major Laws
Key takeaways
- The Environmental Protection Agency, created in 1970, writes most national pollution rules, but states issue most permits and do most enforcement.
- The Clean Air Act, Clean Water Act, and Safe Drinking Water Act, all passed in the 1970s, are the core laws. Air pollution from six common pollutants fell about 78 percent from 1970 to 2020.
- In February 2026 the EPA repealed its 2009 finding that greenhouse gases endanger health, along with vehicle climate standards, and two dozen states sued.
- The Supreme Court narrowed the wetlands covered by the Clean Water Act in 2023, and a new definition was still being written in 2026.
- National limits on PFAS forever chemicals in tap water were set in 2024 and partly rolled back in a 2026 proposal.
- The National Environmental Policy Act and the Endangered Species Act also shape projects, and both were narrowed in 2025 and 2026.
In the late 1960s, rivers caught fire, smog hid city skylines, and pesticides threatened the bald eagle. In just a few years Congress passed the laws that still govern pollution, and President Nixon created the Environmental Protection Agency to carry them out.
This guide explains who does what, from the EPA to state environmental agencies, the major laws, their results, and the current fights over climate, wetlands, and chemicals.
Air and water are far cleaner than in 1970, and both parties claim credit for laws passed with bipartisan votes. Supporters of the 2025 and 2026 rollbacks say rules had grown too costly, exceeded what Congress authorized, and burdened energy, farming, and construction. Critics, including many states, health groups, and scientists, say the changes will increase pollution, harm health, and slow action on climate change, and that cuts at the EPA weaken enforcement. Many of the changes are being fought in court, and some states are setting their own stricter rules.
The Clean Air Act of 1970 requires the EPA to set national limits for common pollutants such as ozone, particles, and lead, and states must write plans to meet them. It also limits emissions from power plants, factories, and vehicles, and the 1990 amendments cut acid rain through a trading program. California can seek waivers to set stricter vehicle rules, but Congress revoked its electric vehicle waivers in June 2025. After the Supreme Court held in 2007 that greenhouse gases are pollutants, the EPA found in 2009 that they endanger health. On February 12, 2026, the EPA repealed that finding and vehicle greenhouse gas standards, and 24 states and health and environmental groups sued.
The Clean Water Act of 1972 makes it illegal to discharge pollution into the nation's waters without a permit, and the Army Corps of Engineers issues permits to fill wetlands. Which waters count has been disputed for decades. In Sackett v. EPA in 2023 the Supreme Court limited federal protection to wetlands with a continuous surface connection to larger waters, and the EPA and Army proposed a narrower definition in 2025 that was still pending in 2026. Waters outside federal protection depend on state law, which varies widely. Runoff from farms and cities, largely left to the states, remains a major problem.
The National Environmental Policy Act of 1970 requires agencies to study the environmental effects of major projects, and the Endangered Species Act of 1973 protects listed species and their habitats. Both were narrowed in 2025 and 2026: the Supreme Court limited the scope of environmental reviews in May 2025, and the wildlife agencies rescinded the habitat-based definition of harm in July 2026. The Court's 2022 major questions ruling and its 2024 decision ending Chevron deference give judges more power to reject agency interpretations of environmental laws.
The Safe Drinking Water Act of 1974 sets limits for more than 90 contaminants in tap water from about 150,000 public water systems, and most states enforce it. Private wells are not covered. The Flint, Michigan, lead crisis that began in 2014 led to new rules and 15 billion dollars from the 2021 infrastructure law to replace lead pipes. In 2024 the EPA set the first limits on PFAS forever chemicals, and in May 2026 it proposed dropping limits on four of six and giving utilities until 2031 to meet the rest.
President Nixon created the Environmental Protection Agency on December 2, 1970, by combining pollution programs scattered across several departments. It sets national standards, approves state plans, and enforces the law, with headquarters in Washington and ten regional offices. It had about 14,700 employees at the end of 2025, down about 14 percent in a year. Under a system called cooperative federalism, most states run their own permit and enforcement programs under federal rules, and states can set stricter standards. The White House Council on Environmental Quality coordinates policy across agencies.
See who manages the land itself in who manages public lands, how agencies write rules in how federal regulations are made, or the court rulings that limit agencies in the administrative state explained.