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Safe Drinking Water Quality

Safe drinking water is essential for daily life. It is also one of the world’s most valuable resources. How often do you think about your tap water quality? The Town of Gilbert takes it seriously and consistently makes sure it is safe and available to you when you turn on the faucet.

Consumer Benefits:

  1. Safe, Convenient, affordable
  2. Public health protection
  3. Economic support and development
Water quality control involves the use of the best available technology within economic limits from the protected raw water source to the required treatment and to the distribution system leading to the ultimate consumer’s tap.

Drinking Water Quality Standards and Guidelines

The Safe Drinking Water Act (SDWA) is the main federal law that ensures the quality of Americans' drinking water. Under SDWA, U.S. Environmental Protection Agency (EPA) sets standards for drinking water quality and oversees the states, localities, and water suppliers who implement those standards. The U.S. EPA has set standards for more than 80 primary contaminants that may occur in drinking water and pose a risk to human health. These standards, called maximum contaminant levels, are the safety limits established for safe drinking water.

Monitoring Drinking Water Quality

The Town of Gilbert Water Quality staff performs up to 100 tests daily in the drinking water you receive at your home or business. These tests ensure that your water meets every health and safety standard set by the state and federal government. The Town of Gilbert has a State certified laboratory that analyzes daily process, distribution and regulatory compliance samples. For complete in-depth analyses, we also use commercial state certified labs. Our staff works to ensure compliance with all drinking water regulations and helps with new rule implementation.
Town of Gilbert meets the following water quality standards:

Testing Requirements and Results for Lead and Copper:

Gilbert collects water samples from 50 houses every three years, which is reduced monitoring that the town has qualified for with historically low levels of lead and copper. Gilbert will be conducting lead and copper testing this summer, 2016. Under the EPA’s lead and copper rule, lead and copper is tested in customer residences selected based on criteria which make them more likely to have plumbing in their homes which contains lead solder, or more likely to have lead service lines. The lead and copper rule requires that water systems maintain lead concentrations less than 15 ppb in more than 90% of samples collected from customer taps. During Gilbert’s last sampling under the lead and copper rule, 15 of the 56 homes surveyed had detectable concentrations of lead, none of which were over the EPA’s action level. Below is a comparison of Gilbert’s lead testing results as compared to Flint’s results listed in their 2014 CCR, and their October 2015 quarterly water quality report.


Gilbert, AZ
Lead & Copper Results (2013)

Flint, MI
Lead & Copper Results (2014)

Flint, MI
Lead & Copper Results (October 2015)

Highest Result

10 ppb

>15 ppb

>15 ppb

90th percentile

3.6 ppb

6 ppb

not listed

EPA Action level

15 ppb

15 ppb

15 ppb

Number over AL




Number of homes tested




Drinking Water Source

Surface water is a primary water source for the Town of Gilbert. Surface water is supplied via canal system from the Salt River Project (SRP) and Central Arizona Project (CAP). SRP manages several dams and reservoirs on the Salt and Verde rivers. Water collected from these rivers into reservoirs is released into SRP canals. CAP's 336 mile long system carries Colorado River water from Lake Havasu, through Phoenix, to south of Tucson.

Where Does Our Drinking Water Come From?

  • SRP - snow and rain runoff from the watersheds in Arizona. For more information, please visit SRP Canals and Dams
  • CAP - water from the Colorado River watershed – Please visit CAP Water Quality
  • Groundwater - water pumped from underground wells

Water Treatment - The Town of Gilbert has two drinking water treatment plants:

North Water Treatment Plant (NWTP): Called NWTP due to its location on the north side of the town. The NWTP is situated on the eastern canal receiving water from the SRP (mixture of salt river and verde river). Water delivered from the NWTP is treated using the conventional methods of coagulation, flocculation, sedimentation, and filtration. The NWTP can produce as much as 45 million gallons of water per day (MGD) and has a 16 million gallon (MG) reservoir onsite for water storage.

North Water Treatment Plant Brochure

Santan Vista Water Treatment Plant (SVWTP): Called Santan Vista because of the stunning view of the Santan moutains from the plant control room. This plant is receiving water from CAP (Colorado river watershed). From CAP turnout, water is brought to the plant through approximately 14 miles of 48” ductile iron pipeline. This plant is built and operating in partnership with City of Chandler. Initial capacity for this plant is 24 MGD; 12 MGD for the town and 12 MGD for the City of Chandler. This plant is treating the water using ballasted flocculation and average process time is 20-25 minutes. Onsite reservoir capacity is 6 MGD.

Santan Vista Water Treatment Expansion Project

Santan Vista Water Treatment Plant Brochure


Groundwater availability from wells is nearly 44 MGD, not including reservoir storage, and is also delivered to the customers via the distribution system that uses chlorine as disinfectant. Groundwater is pumped from 17 wells located throughout the town. Groundwater is used to meet the high demand and during canal dry outs for maintenance. Groundwater can be pumped directly in the distribution systems or can be used to fill a reservoir. In total, the Town of Gilbert can produce approximately 101 MGD and has storage capacity of just over 45 MG and can more than meet the demands from the community which has now grown to over 205,000 residents.


Water is disinfected before it enters the distribution system to ensure that dangerous microbial contaminants are killed. Ozonation and chlorination are used as the means of disinfection for drinking water from the water treatment plants. Water is then delivered to the community through the distribution system of over 700 miles of pipe line at a pressure of 60-80 pound per square inch (psi).