Water Quality Monitoring Program
Tucson Water tracks water quality throughout the Tucson Water system to assure delivery of the highest quality water to all Tucson's customers. Tucson Water is a leader among public utilities in the development of its monitoring program, performing:
Routine Sampling
Routine sampling at over 250 permanent water sampling taps installed throughout the distribution system. Tucson Water measures over 150 water quality parameters at each of these sites. Tucson Water monitors all 250+ sites at least once each month for bacteria and chlorine residual, while all other parameters are monitored once every quarter (every three months).
Routine sampling taps are located throughout Tucson Water's distribution system. There are several taps located in each of the water quality zones. Based on the water quality measurements collected each month from these sampling locations and those at the POEs, the trends in water quality conditions for each water quality zone are determined (see Water Quality In My Neighborhood for water quality charts, tables, and maps).
Continuous Online Monitoring
Tucson Water 
is conducting continuous online monitoring at 22 locations selected specifically to track the delivery of Tucson's various water resources throughout the main distribution system. Online instruments have been installed at all 22 locations to continuously track those water quality measures most important to Tucson's customers — namely, chlorine residual, total dissolved solids, pH, and temperature.
The Clearwater Project represents a vastly important step toward the development of renewable drinking water resources for the City of Tucson. Success is keyed to the delivery of a water supply that meets all of the health and aesthetic goals of Tucson's customers. Tracking the water quality of Clearwater and all other water resources is critical to Tucson Water, and to address this concern, we have implemented a continuous online monitoring program. Since 2001, Tucson Water has been tracking real-time water quality throughout the distribution system, having selected 22 key locations for this purpose.
The water quality parameters measured using online instruments at these sites include: chlorine residual, conductivity, total dissolved solids, pH, and temperature. Additional sampling is performed once a month for such water quality parameters as nitrate, sodium, hardness, and fluoride. This special monitoring program will provide information Tucson's water customers on the water quality throughout Tucson's distribution system (see Tucson's Water Quality for charts, tables, and maps of water quality information).
Point-of-Entry (POE) Sampling
Point-of-Entry sampling is performed to assure the highest quality water enters Tucson's distribution system and that compliance with all federal and state water quality standards are continuously met. Points-of-Entry or POE is the term used to describe the location where the water from a well (or wellfield) enters Tucson's distribution system after being chlorinated. The water quality at the POE locations represents the water quality for each of the major water resources that supply Tucson's drinking water: Clearwater, South Avra Valley wells, Central wells, TARP, South Side wells, and the Santa Cruz wells. Tucson operates over 175 wells that enter the distribution system directly. These wells and the new Clearwater supply represent points-of-entry to Tucson's distribution system and are monitored routinely for their water quality. In particular, these sites are monitored to determine compliance with all health-based drinking water standards. Tucson Water continues to be in compliance with all federal and state drinking water standards. In fact, the information provided to all Tucson Water customers in our Annual Water Quality Reports are based on POE monitoring data. For more information on Tucson Water's compliance status, check out the Arizona Department of Environmental Quality website at http://www.azdeq.gov/environ/regional/sro/empact.html.
