Comparing Metro Phoenix
Water Quality
Description: Drinking water in the United States is heavily regulated by the Environmental Protection Agency (EPA). With nearly 170,000 public water systems, the tap water in the US is among the safest in the world. This is accomplished through stringent monitoring programs. There are about 90 regulated contaminants for drinking water systems. The rules associated with regulations change almost annually, as new contaminants are identified and monitoring and treatment methodology is revised. Drinking water systems are measured for:
- Levels of contaminants that exceed maximum permissible allowances, also called maximum contaminant levels MCL)
- Techniques applied to treat water to make it safe
- How and when systems are monitored and reported in compliance with the law.
The graphs below identify violations of maximum contaminant levels (MCLs), as well as monitoring and reporting violations for water systems in Metropolitan Statistical Areas (MSAs) surrounding the 10 comparator cities.
Rationale: Residents depend on consistent, safe drinking water to ensure a basic quality of life. When water systems are in violation of standards, or if there are errors in treatment or measurement, human health is put at risk, supplies may be suspended, and people lose confidence in the safety of the water supply.
Source: Decision Center for a Desert City (DCDC) using records from the U.S. Environmental Protection Agency's Safe Drinking Water Information System (SDWIS), (acquired January 2006).
