In 1974, Congress passed a landmark bill that has gone a long way toward protecting the health of U.S. citizens. The Safe Drinking Water Act of 1974 authorized the U.S. Environmental Protection Agency (EPA) to establish and institute limits on the amount of contaminants in the country’s public water supply. By and large, tap water in the United States became a lot safer, (though we still recommend filtering it to get rid of trace amounts of impurities).
However, it is important that U.S. citizens understand that this act does not cover all water sources in the United States. If your tap water is sourced from a well, it is not regulated by the Safe Drinking Water Act or the EPA. That means every time you turn on the tap you have no way of knowing if the water coming out of the faucet is safe.