Final answer:
The Safe Drinking Water Act was passed in 1974 to standardize drinking water quality across the United States.
Step-by-step explanation:
The year the Safe Drinking Water Act was passed is 1974. Before its enactment, public drinking water supplies in the United States were managed at the state level, leading to varying standards.
The introduction of the Safe Drinking Water Act by the Environmental Protection Agency (EPA) aimed to standardize water quality and safety across the country.
This landmark legislation has undergone several amendments, like those in 1986 and 1996, to enhance the protection of public water systems and to increase the list of regulated contaminants.