Contaminants detected in water samples throughout the country pose health risks but are perfectly legal. Most people turn on their tap water and think: It's clear, I live in America, we have these laws, I'm being protected," said Nneka Leiba, director of the Healthy Living Science Program for the Environmental Working Group (EWG). In 1974, Congress enacted the Safe Drinking Water Act, authorizing the Environmental Protection Agency (EPA) to set national standards for drinking water. However, it has been more than 20 years since the EPA has added a new contaminant to its list of regulated drinking water pollutants. "The list of regulated chemicals has not kept up with our use of chemicals as a country," Leiba said. EWG collected data from drinking water tests ... at more than 48,000 water facilities throughout the U.S., looking for 500 unique contaminants. The group found 267 present in water supplies, many at levels above what scientific studies have found pose health risks but are still legal under the Safe Drinking Water Act. EWG's findings: 93 of the contaminants were linked to an increased risk of cancer; 78 were associated with brain and nervous system damage; 63 were connected to developmental harm in children or fetuses; 38 were contaminants that could cause fertility issues; and 45 were endocrine disruptors. More than 40,000 water systems had levels of known or likely carcinogens that exceeded health guidelines.