Every day in Arizona, more than 6 million people are provided potable water from approximately 1,500 regulated public water systems (PWSs). The vast majority of these regulated PWSs provide drinking water that meets all state and federal primary (health-based) drinking water standards.

Since 1974, the Environmental Protection Agency (EPA) has set national safety standards for more than 80 contaminants that may be found in drinking water. Once the EPA develops a new standard, the rule is sent to the states, and the states adopt and build upon the standard based on their own laws and rules. In Arizona, the EPA has granted ADEQ the right and responsibility to oversee drinking water rules and programs.¹

While ADEQ adopts, builds upon and enforces drinking water standards, local governments and private water suppliers are responsible for the quality of the water that flows to the tap. Water systems test and treat their water, maintain the distribution systems that deliver the water, and report on their water quality to the state. ADEQ provides technical assistance to water suppliers and can take legal action against systems that fail to provide water that meets these standards.

To help PWSs stay in compliance, ADEQ provides various resources for drinking water rules | Learn More >