The city of Flagstaff is sending out notices to municipal water customers in the neighborhood northwest of Sinagua Middle School after drinking water at one monitoring location exceeded maximum contaminant levels for haloacetic acids.
These types of acid compounds form when disinfectants such as chlorine react with naturally occurring organic and inorganic materials in the water.
The customers affected are in a triangle roughly bordered by Interstate 40, East Butler Avenue and Fourth Street. In addition to Sinagua Middle School, they include Knoles Elementary School, Northland Preparatory Academy and Little America.
The one-year rolling average concentration of haloacetic acids at one of eight sampling locations throughout the city was .06175 milligrams per liter, which is 3 percent above the maximum contaminant level of .060 milligrams per liter. The maximum contaminant levels are set by the U.S. Environmental Protection Agency. Below them, no adverse health effects are likely to occur.
According to the EPA, some people who drink water containing haloacetic acids in excess of the maximum contaminant levels over many years may have an increased risk of getting cancer.
The city stressed that this is not an emergency and residents who receive the notice do not need to boil their water. Residents who have a severely compromised immune system, who have an infant or elderly may however be at increased risk and should seek advice from their healthcare providers about drinking the water.
The other seven monitoring locations throughout the city did not exceed the maximum contaminant level for haloacetic acids. Water outside the specific area also did not exceed the contaminant level. The city has retained a consultant to help identify the reason for, and correct the exceedance.