Metro Water District

Water Quality

Metro Water District regularly checks its water for contaminants. The District is required by federal and state regulations to test for 166 constituents. Staff collects water samples from wells, storage facilities, points in the distribution system, and at residents' homes. The samples are then taken to state licensed laboratories for analysis. Annually, a water quality report (consumer confidence report) is sent to all residents within the District per Environmental Protection Agency (EPA)'s Safe Drinking Water Act. Metro Water is active in tracking as well as being involved with water quality regulations

Metro Main Annual Water Quality Report
Metro Hub Annual Water Quality Report
Metro Southwest - Diablo Village Annual Water Quality Report
Metro Southwest - Lazy B Annual Water Quality Report
Metro Southwest - E&T Annual Water Quality Report

Water Hardness – The systems are interconnected in some areas so water is blended and concentrations may vary. 

Metro Main Hardness Levels
Metro Hub Hardness Levels
Metro Southwest - Diablo Village Hardness Levels
Metro Southwest - Lazy B Hardness Levels
Metro Southwest - E&T Hardness Levels

Fluoride and Sodium Levels – The systems are interconnected in some areas, so water is blended and concentrations may vary. 

Metro Main Fluoride and Sodium Levels
Metro Hub and Metro Southwest Fluoride and Sodium Levels

Treatment – The District does treat its water with chlorine. The District began to add chlorine in 1994 when a few service areas tested positive for total coliform bacteria. The District added chlorine to eliminate any type of bacterial contamination that could occur in the water pipes. Since 1995, Metro Water has not had further problems with bacterial contamination.

Additionally, a water treatment system is in place at the South Shannon well site. In 1994, the District detected traces, but not violations, of two volatile organic compounds (VOCs) at the South Shannon well. While the water met drinking standards, the District sought to remove the VOCs. In July 1997, a treatment system began operation. Subsequently, the treatment system has consistently provided to customers in the South Shannon service area water free of VOCs. The District upgraded that treatment system in 2006 and the new system paid by ADEQ was dedicated in February 2007. The South Shannon well site is located in the Shannon Road-Rillito Creek superfund site area that ADEQ is responsible for overseeing the clean up of the groundwater contamination. To date, this effort has focused on determining the source of the groundwater contamination. ADEQ has reimbursed the District for operation costs of the treatment system, which have totaled over a million dollars since the year 2000.

Arsenic – In 2001, the EPA changed the drinking water standard for arsenic from 50 parts per billion (ppb) to 10 ppb in water delivered to customers. Water providers were to comply by 2006. All of Metro Main's wells are under 10 ppb. Two wells in Metro Hub and two in Metro Southwest have treatment systems to ensure compliance with the arsenic rule. 

Arizona Department of Environmental Quality – ADEQ is the state regulatory department that overseas water quality. The District works closely with ADEQ to ensure compliance in the various regulatory requirements. All constituent sample test results are reported to ADEQ.

Future – Other new rules being discussed by EPA are being tracked, particularly rules relating to 1-4 dioxane, hexavalent chromium, emerging contaminants, radon, and a revision to volatile organic compounds.


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  • © Metropolitan Domestic Water Improvement District
  • 6265 N. La Cañada, Tucson, Arizona 85704
  • 520-575-8100 (office)
  • 520-575-8454 (fax)

Office hours: Monday – Thursday 7:30am - 5:30pm and Friday 7:30am - 12 noon