Water in south Peoria violated a drinking water standard set by the U.S. Environmental Protection Agency, according to a city notice.
But officials say there is no emergency and no immediate health risk.
A group of chemicals, total trihalomethanes, or TTHMs, was found in July to be slightly above the recommended parts per billion at a monitoring station near 71st and Olive avenues, according to the city.
TTHMs form when chlorine that keeps water safe from bacteria reacts with natural organic matter in the water, said Chris Gold, Peoria's environmental compliance supervisor, in a statement. They are common in chlorinated water systems across the country, Gold said.
Caroline Oppleman, a spokesperson for the Arizona Department of Environmental Quality,
said TTHM drinking water standards are based on possible health risks associated with long-term exposure, rather than short-term consumption.
Peoria, in its notice, said excess consumption and long-term exposure to TTHMs could lead to problems with a person's liver, kidney or central nervous system and a possible increased risk of getting cancer.
Oppleman confirmed that the violation in Peoria was not an emergency.
What happened when Peoria's water was tested?
Peoria tests its water quarterly. After a compliance test in July, officials learned that between October and early July, the average TTHM level at a south Peoria monitoring station was about 82 parts per billion. The federal standard is 80 parts per billion.
The issue was localized to that part of Peoria, according to Gold, and includes city water customers south of Bell Road. Peoria city limits stretch as far south as Northern Avenue.
"Water in this part of the system spends more time in the pipes before reaching taps, especially during summer heat," Gold said. "The longer water sits, the more TTHMs can form."
All other stations were below the federal compliance standard, according to a chart that Gold shared.
Is the water safe?
The water is safe for drinking, cooking, bathing and all normal use, Gold said.
Residents do not need to boil water or take any other corrective action, according to Peoria's notice. If the water becomes unsafe to drink, the city will notify the public within 24 hours.
However, the following groups should seek advice from their health care provider about drinking water in that area because they may be at increased risk: people with severely compromised immune systems, people who are pregnant or have infants and the elderly.
How has the city responded?
Peoria swiftly took steps to lower the TTHM levels in the affected area.
This has included flushing water lines more often to keep fresh water moving through the area and identifying where equipment that would flush lines automatically could be installed when needed, according to the city.
The water has been tested weekly and, so far, the city's actions have been working. Gold said the affected area would return to compliance levels before the next compliance test in October.
Elena Santa Cruz covers the West Valley cities of Glendale, Surprise and Peoria. Reach her at elena.santacruz@arizonarepublic.com or follow her on X @ecsantacruz3.
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This article originally appeared on Arizona Republic: Peoria water is safe to drink despite violating EPA standard, city says
