Since 2004, 20% of America’s water treatment systems have been guilty of violations of the Safe Drinking Water Act, according to an analysis of federal data. The Act mandates that communities deliver safe tap water to residents. But over the past five years, water provided to over 49 million Americans has contained illegal amounts of chemicals such as arsenic or radioactive substances such as uranium, and harmful bacteria that’s usually found in sewage. Regulators were informed of violations, but records indicate that less than 6% of systems that violated the law were punished or fined. Research shows that contaminants in drinking water are linked annually to millions of cases of illness within the U.S. The Environmental Protection Agency (EPA), which has ultimate regulatory and enforcement authority on the federal level, plans a new policy for policing America’s 54,700 water treatment systems. Water pollution is a growing concern for many lawmakers as government oversight has rolled back in recent years. U.S. Senator Barbara Boxer, a California Democrat, asked the EPA in 2007 for data on the exposure of Americans to drinking water contaminants. An analysis shows that drinking water violations of the Safe Drinking Water Act have occurred in every state. Since 2004, the majority of violations have occurred at systems that serve fewer than 20,000 residents. It isn’t clear exactly how many illnesses are linked to contaminated water. The most harmful contaminants have been tied to diseases that can take years to develop, like cancer. But research shows that as many as 19 million Americans annually may become ill due to parasites, viruses and bacteria found in drinking water. Certain diseases, like prostate and breast cancer, have increased over the past 30 years, and studies show they are tied to pollutants like the ones found in drinking water. In response to Senator Boxer, the EPA says that, since 2005, more than three million Americans have been exposed to drinking water with containing arsenic and radioactive elements, which have been linked to cancer. In certain places, radium detected in drinking water was 2,000% higher than the legal limit. But regulators fined or punished less than 8% of systems that violated arsenic and radioactive standards. And more than a quarter of systems that violated the arsenic or radioactivity standards were contacted by regulators, even after revealing their violations.