2017 Water
Quality
Consumer
Confidence
Report Issued 2018
DIRECTOR'S MESSAGE Everything begins with water. There isn't much you can do without this precious resource, especially in the arid Southwest. For cities to grow and thrive, water utilities have to keep up with the demands of the booming economy in Arizona. The City of Mesa Water Resources Department is well positioned to continue to meet the needs of our community with safe and reliable water services.

I am proud to announce that in the summer of 2018, the new $126 million Signal Butte Water Treatment Plant will be brought online to service southeast Mesa. As one of the largest capital projects in Mesa's history, the Signal Butte Water Treatment Plant will add another 24 million gallons per day of capacity to our system, enabling the City to supply anticipated residential and commercial development. Using the latest in water treatment technology, including ozone disinfection, this new plant will provide safe and clean drinking water sourced from the Central Arizona Project (Colorado River) Canal.

At the City of Mesa, we are always looking toward the future with a focus of quality, reliability, value and service. I encourage you to read this report that contains important information about your water services and contact us with any questions.

Jake West
Director, City of Mesa Water Resources
PROVIDING QUALITY WATER FOR OVER A CENTURY For over 100 years, the City of Mesa has been committed to providing its customers with water that meets more than 100 state and federal drinking water standards. Our number one goal is to provide you and your family with a safe and dependable supply of drinking water. We are happy to report that in 2017, your tap water met all drinking water health standards. The City of Mesa vigilantly safeguards its water supplies and we are proud to provide this summary report detailing our monitoring efforts.
18,500 water analyses conducted
3,100 samples
collected
WHY YOU SHOULD READ THIS REPORT This report contains important information about the water you drink and use every day. You will find details about where your water comes from, the testing that was performed, and what was found in the water we deliver to you. To ensure tap water is safe to drink, the U.S. Environmental Protection Agency (EPA) established regulations that limited the amount of contaminants in water provided by public water systems. This report is a snapshot of the most recent water quality monitoring conducted by the City of Mesa and how your water measures up to those limits.

Questions about drinking water are important and answers to many common questions can be found in this report. Additional questions or comments can be directed to the city, state or federal contacts listed below.

Este informe contiene información importante acerca de su agua potable. Este informe está disponible en Español. Llame at (480) 644-6461 para obtener el folleto en Español, o hable con alguien que lo entienda.

Mesa’s highly trained water quality inspectors, analysts, chemists and water treatment specialists are responsible for assuring high quality water is consistently delivered to your home. This report reflects data from over 18,500 analyses conducted on approximately 3,100 samples collected to meet regulatory and process requirements. Water is tested daily, weekly and monthly at Mesa’s state-certified laboratory and by outside laboratories. These tests are overseen by various federal, state and local regulatory agencies.
DRINKING WATER CONTAMINANTS Drinking water sources (both tap water and bottled water) include rivers, lakes, streams, ponds, reservoirs, springs and wells. As water travels over the surface of the land or through the ground, it dissolves naturally occurring minerals and, in some cases, radioactive material, and can pick up substances resulting from the presence of animals or human activity. The sources of Mesa’s drinking water are further discussed below.
CONTAMINANT INFORMATION Both tap water and bottled water may realistically be expected to contain at least small amounts of some contaminants. The presence of contaminants does not necessarily indicate that water poses a health risk to you and your family. The EPA prescribes enforceable regulations that limit the amount of certain contaminants allowed in water provided by public water systems. Bottled water is regulated by the U.S. Food and Drug Administration (FDA) as a food product and is required to meet standards equivalent to those the EPA sets for tap water. More information about contaminants and potential health effects can be obtained by calling EPA’s Safe Drinking Water Hotline (800) 426-4791 or visiting www.epa.gov/ground-water-and-drinking-water/safe-drinking-water-hotline.
CONTAMINANTS PRESENT MAY INCLUDE: Microbial contaminants, such as viruses and bacteria that may come from sewage treatment plants, septic systems, agricultural livestock operations, recreational activities and wildlife.

Inorganic contaminants, such as salts and metals, which can be naturally occurring or result from urban stormwater runoff, industrial or domestic wastewater discharges, oil and gas production, mining or farming.

Pesticides and herbicides, which may come from a variety of sources such as agriculture, urban stormwater runoff and residential uses.

Organic chemical contaminants, including synthetic and volatile organic chemicals that are by-products of industrial processes and petroleum production, and can also come from gas stations, urban stormwater runoff and septic systems.

Radioactive contaminants, which can be naturally occurring or be the result of oil and gas production and mining activities.
FACTS ABOUT COLIFORM BACTERIA Coliform bacteria are common microbes used as indicators of drinking water quality. Coliform bacteria are generally not harmful and are naturally present in the environment. They serve as an indicator of the sanitary quality of your drinking water. Samples are collected weekly throughout Mesa’s water system to confirm these bacteria are not present in your water. Results from our 2017 coliform monitoring are found in the table below.
ADDITIONAL INFORMATION ABOUT NITRATE, LEAD, RADON AND ARSENIC Nitrate - Nitrate in drinking water at levels above 10 ppm is a health risk for infants of less than six months of age. High nitrate levels in drinking water can cause blue baby syndrome. Nitrate levels may rise quickly for short periods of time because of rainfall or agricultural activity. If you are caring for an infant, you should ask for advice from your healthcare provider. Nitrates are monitored annually in both groundwater and finished surface water sources. None of Mesa’s water sources exceed the EPA’s limit for nitrate (measured as nitrogen) set at 10 ppm. Monitoring results can be found in the table below.

Lead and Copper - If present, elevated levels of lead can cause serious health problems, especially for pregnant women and young children. Lead in drinking water is primarily from materials and components associated with service lines and home plumbing. The City of Mesa is responsible for providing high quality drinking water, but cannot control the variety of materials used by homeowners in plumbing components. When your water has been sitting for several hours, you can minimize the potential for lead exposure by flushing your tap for a minimum of 30 to 60 seconds before using water for drinking or cooking. If you are concerned about lead in your drinking water, you may want to have your water tested. Information on lead in drinking water, testing methods, and steps you can take to minimize exposure is available from the Safe Drinking Water Hotline or at www.epa.gov/your-drinking-water/safe-drinking-water-hotline. Mesa monitored for lead and copper in 2015 at 50 homes throughout the community. The action levels established by EPA are 1300 parts per billion (ppb) for copper and 15 ppb for lead. Compliance with this requirementis based on 90% of the samples being below the action levels. From the samples taken in 2015, the 90th percentile value for copper was 89 ppb and for lead 4.3 ppb. The action level for lead and copper was not exceeded in any of the 50 samples collected. Mesa will test for lead and copper in residential plumbing again in 2018 to comply with the EPA Lead and Copper Rule. Monitoring results can be found in the table below.

Radon - Radon is a radioactive gas found throughout the U.S. that you cannot see, taste or smell. Radon can move up through the ground and into a home through cracks and holes in the foundation, building up to high levels. Radon can also get into indoor air when released from tap water from showering, washing dishes and other household activities. Compared to radon entering the home through soil, when it enters the home through tap water it will, in most cases, be a small source of radon in indoor air. Radon is a known human carcinogen. Breathing air containing radon can lead to lung cancer. Drinking water containing radon may also cause increased risk of stomach cancer. If you are concerned about radon in your home, test the air in your home. Testing is inexpensive and easy. You should pursue radon removal for your home if the level of radon in your air is four picocuries per liter of air (pCi/L) or higher. There are simple ways to fix a radon problem that are not costly. For additional information, call your state radon program or call EPA’s Radon Hotline at (800) SOS-RADON.

Arsenic - Some of Mesa’s drinking water sources contain low levels of arsenic, a naturally occurring metal. Beginning in January 2006, allowable arsenic levels were reduced from 50 ppb to 10 ppb. The EPA determined this standard by balancing the current understanding of arsenic’s possible health effects against the costs of removing it from drinking water. The EPA continues to research the health effects of low-level exposure to arsenic. Some people who drink water containing arsenic in excess of the MCL over many years could experience skin damage or problems with their circulatory system and may have an increased risk of getting cancer. Mesa did not exceed the MCL for arsenic in any water delivered to customers in 2017. Monitoring results can be found in the table below.
SOURCE WATER ASSESSMENT A source water assessment identifies potential sources of contaminants to the water we use for drinking. The Arizona Department of Environmental Quality (ADEQ) reviewed adjacent land uses and ranked them as to their potential to affect Mesa’s water sources. These risks include, but are not limited to, gas stations, landfills, dry cleaners, agricultural fields, wastewater treatment plants and mining operations. In 2004, the ADEQ completed a source water assessment of Mesa’s wells and one surface water treatment plant. The result of Mesa’s assessment was high-risk due to some industries located in the city. However, this does not mean the drinking water is compromised, only that at least one high-risk activity was identified. The complete assessment can be reviewed at ADEQ, 1110 W. Washington Street, Phoenix, Arizona 85007, between 8 a.m. and 5 p.m. You can request an electronic copy via e-mail at dml@azdeq.gov. For more information visit ADEQ’s Source Water Assessment and Protection Unit Web site at www.azdeq.gov/environ/water/assessment/index.html.
TAKING PRECAUTIONS FOR SPECIAL HEALTH CONCERNS Some people may be more vulnerable to contaminants in drinking water than the general population. Immunocompromised people such as persons undergoing chemotherapy, people who have undergone organ transplants, people with HIV/AIDS or other immune system disorders, some elderly, and infants can be particularly at risk from infections. These people should seek advice about drinking water from their healthcare providers. EPA and Centers for Disease Control guidelines on appropriate means to lessen the risk of infection by Cryptosporidium and other microbial contaminants are available from the Safe Drinking Water Hotline at (800) 426-4791 or at www.epa.gov/your-drinking-water/safe-drinking-water-hotline.
UNREGULATED CONTAMINANT MONITORING RULE 3 Unregulated contaminant monitoring helps the EPA determine if specific contaminants occur in the nation’s drinking water and whether those contaminants need to be regulated. The Unregulated Contaminant Monitoring Rule 3 (UCMR3) specified 29 contaminants of emerging concern (CECs), and required every water system in the United States to sample for them. Mesa conducted UCMR3 monitoring from January 2013 to January 2015 at all of the source water “Entry Points to the Distribution System” and at corresponding “Distribution System Maximum Residence Time” locations within the water system. Mesa detected 10 of the 29 CECs either in the source water or in the distribution system. The Unregulated Contaminant Monitoring table summarizing results from the UCMR3 monitoring is provided in this report below. Mesa will begin sampling for UCMR4 beginning July 2018. For more information about UCMR4, visit www.epa.gov/dwucmr/fourth-unregulated-contaminant-monitoring-rule.
MESA'S WATER SOURCES Mesa relies on two sources for its drinking water: surface water and groundwater wells. Water from these two sources can vary in hardness and other characteristics. The city is divided into two zones - the “City Zone” and the “Eastern Zone” - with the Eastern Canal serving as the dividing line between the two zones. The canal runs diagonally southeast from Gilbert and McDowell Roads to Greenfield and Baseline Roads. The zone you live in determines whether the water you receive originated from surface water, a groundwater well or a mixture of both.
City Zone - Salt and Verde River water from the Salt River Project (SRP) supplies water delivered in the City Zone. This water is treated at the Val Vista Water Treatment Plant by using conventional filtration, fluoridation, and disinfection using chlorine dioxide and chlorine before entering into Mesa’s water distribution system. Approximately 26 percent of all the water served to Mesa’s customers in 2017 came from this source.

Eastern Zone - Colorado River water delivered through the Central Arizona Project (CAP) provides water delivered in the Eastern Zones. This water is treated at the CAP Brown Road Water Treatment Plant by using conventional filtration, fluoridation, and disinfection using chlorine dioxide and chlorine before entering into Mesa’s water distribution system. Approximately 55 percent of the water served to Mesa’s customers in 2017 came from this source.

City Wells - 16 deep aquifer wells supply drinking water throughout the City Zone. After chlorination, water from these wells is typically blended with surface water from the Val Vista Water Treatment Plant. However, during certain times throughout the year, some customers may receive only groundwater from one or more of these wells. Approximately 12 percent of the water served to Mesa’s customers came from this source in 2017.

Eastern Wells - 15 deep aquifer wells supply drinking water throughout a wide area in Mesa’s Eastern Zones. After chlorination, water from these wells is blended with surface water treated at the CAP Brown Road Water Treatment Plant. Approximately seven percent of the water served to Mesa’s customers came from this source in 2017.
WATER TREATMENT PROCESS
WATER QUALITY DATA The following tables list drinking water contaminants detected in calendar year 2017 and data from the most recent testing done in accordance with the Safe Drinking Water Act. The State allows water systems to monitor for some contaminants less than once per year because the concentrations of these contaminants do not change frequently. Some of the data, though representative, are more than one year-old. The presence of contaminants does not indicate that the water poses a health threat, only that they were detected during routine compliance monitoring. Not listed are many other regulated contaminants that were tested for but not detected.
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PROTECTING OUR WATER QUALITY AND THE ENVIRONMENT Know Your H2O: Water education goes hand-in-hand with water pollution prevention. Mesa has a variety of educational materials, tips, conservation rebate programs, water-efficient landscaping ideas and more to help you get to Know Your H2O, visit www.mesaaz.gov/water.

Keep Our Waterways Clean: When it rains, our yards can become channels to our waterways. A storm can wash fertilizers, herbicides, pesticides and other chemicals from yards into the streets and eventually our waterways. For helpful tips visit www.azstorm.org.

Drain Your Pool Properly: Pool water discharges can contain environmentally harmful pollutants such as excess salts, elevated chlorine and other chemicals, and even nuisances such as mosquito larvae. For helpful tips on how to legally drain your pool, visit www.mesaaz.gov/residents/environmental.

Safely Dispose of Unused Medications: Do not flush unused medications and personal health care products down the sink or toilet because it introduces contaminants into the water supply and environment. Learn how to responsibly dispose of unused medications at www.mesaaz.gov/residents/solid-waste-trash-recycling/prescription-medication-disposal.

How You Can Get Involved: If you wish to provide input on water related issues, the Mesa City Council meets at 5:45 p.m. the first and third Monday of each month in Council Chambers, located at 57 E. 1st Street, unless otherwise noted. For a complete meeting schedule, visit www.mesaaz.gov/city-hall.