Water Quality Monitoring Program

toddler drinking from fountain

Water quality is measured from various monitoring sites and the results are evaluated with EPA standards to ensure the highest quality water is served to our customers.

EPA regulations require water providers to routinely test public drinking water supplies for:

  • Bacteria and other microorganisms.
  • Numerous other naturally-occurring or man-made organic and inorganic constituents.

Tucson Water also tests for additional parameters to further evaluate water quality.

Source or Well Monitoring

  • Tucson Water operates approximately 230 drinking water wells located in 10 Public Water Systems (PWS).
  • The Safe Drinking Water Act requires PWS to monitor their source wells and Entry-Points-to-the-Distribution-System (or EPDS) to ensure compliance with EPA drinking water standards.
  • EPDSs are tested for more than 80 regulated drinking water parameters at established monitoring frequencies.

Distribution System Monitoring

Tucson Water measures more than 150 water quality parameters at 266 permanent water sampling taps located throughout its distribution systems.

Coliform bacteria, disinfection by-products, asbestos, and water quality measurements are some examples of the parameters that are monitored from our water sampling taps.

The results from our distribution system monitoring and EPDS monitoring are used to evaluate the trends in water quality for each water quality zone.

Tap Water Monitoring

The primary source of lead in tap water comes from the pipes and fixtures in individual homes where corrosive water can leach lead from the plumbing fixtures.

How We Monitor:

  • We monitor for lead and copper at 150 Tucson Water customer homes.
  • Participating customers collect their own tap samples and submit the samples for analysis by our state-certified laboratory.
  • If more than 10% of the sites in the Public Water Systems (PWS) exceed the lead or copper action level, the water is corrosive and must be treated.

Continuous Online Monitoring

The Clearwater Project was an important step toward the development of renewable drinking water resources and 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. To do this, we implemented a continuous online monitoring program. The water quality parameters measured using online instruments at these sites include:

  • Chlorine residual
  • Conductivity
  • Total dissolved solids
  • pH
  • Temperature
  • Nitrate
  • Sodium
  • Hardness

Results of the water quality monitoring are compiled and available from Tucson Water's Water Quality page (which includes charts, tables, and maps of water quality information).