Total Coliform Bacteria

The City of Yuma conducts monthly monitoring for Total Coliform bacteria, collecting over 100 samples from locations throughout the water distribution system. This monitoring is performed to verify the integrity of the distribution system and ensure the continued safety of the drinking water supply. A maximum of 5% of these samples may be positive for Total Coliform each month. (Note: If the sample is negative for Total Coliform, it is negative for E. coli). The City of Yuma's drinking water system is operated and monitored in accordance with the Safe Drinking Water Act (SDWA). 

• Total Coliform & E. coli Summary for COY Potable Water

Annual Inorganic Chemical Analysis Report

Each year, we test our drinking water for inorganic contaminants to ensure compliance with the Safe Drinking Water Act (SDWA). These contaminants include substances such as salts and metals, which may originate from natural sources as well as human activities like stormwater runoff, agriculture, mining, and wastewater discharges. The U.S. Environmental Protection Agency (USEPA) establishes Maximum Contaminant Levels (MCLs) for these substances under SDWA to protect public health. Regular monitoring and treatment help ensure the water remains safe for consumption over a lifetime. Samples for inorganic analysis are collected each January, with results typically received by mid-March.

Water Quality Information

The City of Yuma’s potable water system, Public Water System No. 14024, is regulated under the Safe Drinking Water Act (SDWA) and is overseen by the U.S. Environmental Protection Agency (USEPA) and the Arizona Department of Environmental Quality (ADEQ). 

Water Quality Report

The Consumer Confidence Report (CCR) or Water Quality Report is mandated by USEPA to be published and available to the public by July 1st each year. The data reported is for the previous calendar year. For example, the CCR published for July 1, 2025 contains data for January through December 2024.