Denver Water Board 2023 Drinking Water Quality Report PWSID: CO 0116001

The Water Environment Federation and U.S. Environmental Protection Agency recognized Centennial Water with an NSmart award in 2022.

Centennial Water received the award for its nitrogen and phosphorous nutrient removal program at the Marcy Gulch Wastewater Treatment Plant.

Significant Deficiencies

Public water suppliers are required to notify customers of unresolved deficiencies in design, operation, maintenance, administration, or a failure or malfunction in a system component, including sources, treatment, storage or distribution system that have the potential to cause risks to the reliable delivery of safe drinking water.

What happened?

During a sanitary survey in September 2022, inspectors found deficiencies related to cross-connection, storage tanks, operations and storage conditions. There is no evidence that the water you drink was affected by these deficiencies.

1. Cross-connection: Denver Water is working with the state health department to install more crossconnetion devices at Foothills, Moffat and Marston treatment plants.

2. Storage tanks: State inspectors noted deficiencies in the backwash tanks at Foothills, Moffat and Marston treatment plants. Denver Water is repairing the hatch and vent at all three sites, outlined in the corrective action plan, as well as repairing the vent and overflow at Marston. The repairs will be completed by December 2023.

3. Operations: The turbidity sampling lines at Foothills Treatment Plant were sampling incorrectly. Denver Water is replumbing the individual filter effluent turbidity lines in order to fix the sampling method. This will be fixed by September 2023.

4. Storage conditions: State inspectors found that the hatches on Capitol Hill Tank 3, Capitol Hill Reservoir, Lonetree Reservoir and 56th Avenue Tank were installed incorrectly. Denver Water is repairing the hatches according to the corrective action plan. Repairs will be fixed by December, with the exception of the 56th Avenue tank, which will be completed by April 2024.

How did this impact drinking water quality?

There is no evidence that the water you drink was affected by these deficiencies.

What has been done to correct this situation?

In all instances, Denver Water worked quickly with the state health department to develop a corrective action plan and make necessary repairs.

Water Quality Violations

CROSS-CONNECTION

In 2022, Denver Water received two violations under state drinking water regulations. One violation was for six failed backflow test assemblies that were not quickly addressed by the customers. The other violation was for six crossconnections that required backflow protection. There is no evidence that the water you drink was affected.

What should I do?

Although this situation was not an emergency, as our customers, you have a right to know what happened and what we did to correct this situation. There is nothing you need to do. We do not have any evidence that your drinking water was impacted. All of the devices have been repaired and tested. All of the connections are now controlled. If you have specific health concerns, please contact your health care provider

What happened?

On April 26, 2022, and May 5, 2022, Denver Water notified the state health department that in 2020 and 2021, six backflow assemblies with failed tests and six connections without proper protection were not repaired or protected within the required timeframes. Maintaining and protecting these 12 connections is the responsibility of the property owners, and they failed to provide proper documentation that these connections were protected. Under the state health department’s regulations, Denver Water is required to ensure compliance with these devices.

Backflow prevention assemblies prevent contaminants from a property’s irrigation or fire suppression lines and certain domestic lines from entering the public drinking water supply. There are more than 44,000 backflow prevention assemblies connected to Denver Water’s distribution system. State regulations require property owners who have these connections to have their backflow prevention assemblies inspected and certified annually. Uncontrolled cross-connections can lead to a back pressure or siphonage event that may allow contaminants or disease-causing organisms to enter the drinking water, which can cause diarrhea, nausea, cramps and associated headaches.

For most properties, if the backflow prevention assembly is not meeting requirements, Denver Water will shut off water service to the property until the backflow prevention device is in compliance. However, the 12 connections that resulted in the violations are owned by “critical customers,” a category that includes schools, public housing facilities, hospitals and local government facilities.

Denver Water makes every effort to avoid shutting off water to these important public service locations. The water quality violations resulted when the 12 connections were not protected within the required timelines and these property owners did not correct the issues.

How did this impact drinking water quality?

Denver Water constantly monitors water quality throughout the Denver metro area, and our records indicate that your drinking water was not impacted as a result of the 12 noncompliant connections.

What has been done to correct this situation?

Denver Water has notified the property owners that their failure to certify these backflow prevention assemblies and control the identified cross-connections triggered violations of Colorado’s drinking water regulations. All of the devices are now working properly, and the crossconnections have been controlled. Denver Water has reviewed its process with all critical customers to ensure this violation does not occur again. In addition to the multiple notifications already provided to these customers, Denver Water increased the frequency with which it reviews customer compliance data, offers cross-connection control services to noncompliant customers and suspends service for those customers that fail to comply prior to the 120-day regulatory deadline.

For more information about Denver Water’s backflow prevention program or these violations, visit denverwater. org/Backflow.

Turbidity

On Sept. 4, 2022, a filter monitoring instrument at the Moffat Water Treatment Plant reported the same turbidity (cloudiness) value for 17 hours rather than actual turbidity values. The constant value stemmed from a mechanical failure of the instrument. This constituted a monitoring violation for individual filter effluent turbidity. As a result, Denver Water instituted changes to improve monitoring, programming and training to prevent a repeat of this failure in the future. At no time did turbidity in the finished drinking water exceed regulatory standards. Denver Water identified and reported this violation to the state health department.

We are pleased to present to you this year’s water quality report for the City of Aurora service area. Our constant goal is to provide you with a safe and dependable supply of drinking water. Please contact Ortilano Bobby Oligo at 303-739-6740 with any questions or for public participation opportunities that may affect the City of Aurora’s water quality. Please see the water quality data from wholesale system(s) (either attached or included in this report) for additional information about your drinking water.

All drinking water, including bottled water, may reasonably be expected to contain at least small amounts of some contaminants. The presence of contaminants does not necessarily indicate that the water poses a health risk. More information about contaminants and potential health effects can be obtained by calling the Environmental Protection Agency’s Safe Drinking Water Hotline (1-800-426-4791) or by visiting epa.gov/ground-water-and-drinking-water

Some people may be more vulnerable to contaminants in drinking water than the general population. Immunocompromised persons such as persons with cancer undergoing chemotherapy, persons who have undergone organ transplants, people with HIV-AIDS or other immune system disorders, some elderly, and infants can be particularly at risk of infections. These people should seek advice about drinking water from their health care providers. For more information about contaminants and potential health effects, or to receive a copy of the U.S. Environmental Protection Agency (EPA) and the U.S. Centers for Disease Control (CDC) guidelines on appropriate means to lessen the risk of infection by Cryptosporidium and microbiological contaminants call the EPA Safe Drinking Water Hotline at (1-800-426-4791).

The sources of drinking water (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 from human activity. Contaminants that may be present in source water include:

● Microbial contaminants: viruses and bacteria that may come from sewage treatment plants, septic systems, agricultural livestock operations, and wildlife.

● Inorganic contaminants: 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: may come from a variety of sources, such as agriculture, urban stormwater runoff, and residential uses.

● Radioactive contaminants: can be naturally occurring or be the result of oil and gas production and mining activities.

● Organic chemical contaminants: including synthetic and volatile organic chemicals, which are byproducts of industrial processes and petroleum production, and also may come from gas stations, urban stormwater runoff, and septic systems.

In order to ensure that tap water is safe to drink, the Colorado Department of Public Health and Environment prescribes regulations limiting the amount of certain contaminants in water provided by public water systems. The Food and Drug Administration regulations establish limits for contaminants in bottled water that must provide the same protection for public health.

Lead in Drinking Water

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. We are responsible for providing high quality drinking water and removing lead pipes, but cannot control the variety of materials used in plumbing components in your home. You share the responsibility for protecting yourself and your family from the lead in your home plumbing. You can take responsibility by identifying and removing lead materials within your home plumbing and taking steps to reduce your family’s risk. Before drinking tap water, flush your pipes for several minutes by running your tap, taking a shower, doing laundry or a load of dishes. You can also use a filter certified by an American National Standards Institute accredited certifier to reduce lead in drinking water. If you are concerned about lead in your water and wish to have your water tested, contact Ortilano Bobby Oligo at 303-739-6740. Information on lead in drinking water, testing methods, and steps you can take to minimize exposure is available at epa.gov/safewater/lead.

Source Water Assessment and Protection (SWAP)

The Colorado Department of Public Health and Environment may have provided us with a Source Water Assessment Report for the ECCV water supply. For general information or to obtain a copy of the report please visit wqcdcompliance.com/ccr. The report is located under “Guidance: Source Water Assessment Reports.” Search the table using 103005, AURORA CITY OF, or by contacting Ortilano Bobby Oligo at 303-739-6740. The Source Water Assessment Report provides a screening-level evaluation of potential contamination that could occur. It does not mean that the contamination has or will occur. We can use this information to evaluate the need to improve our current water treatment capabilities and prepare for future contamination threats. This can help us ensure quality finished water is delivered to your homes. In addition, the source water assessment results provide a starting point for developing a source water protection plan. Potential sources of contamination in our source water area are listed below. Please contact us to learn more about what you can do to help protect your drinking water sources, any questions about the Drinking Water Quality Report, to learn more about our system, or to attend scheduled public meetings. We want you, our valued customers, to be informed about the services we provide and the quality water we deliver to you every day.

Sources (water type - source type)

NC VW10A (Groundwater UDI Surface Water-Well)

NC VW10 (Groundwater UDI Surface Water-Well)

NC VW11 (Groundwater UDI Surface Water-Well)

NC VW12 (Groundwater UDI Surface Water-Well)

NC VW13 (Groundwater UDI Surface Water-Well)

NC VW14 (Groundwater UDI Surface Water-Well)

NC VW15 (Groundwater UDI Surface Water-Well)

NC VW 16 (Groundwater UDI Surface Water-Well)

NC VW18 (Groundwater UDI Surface Water-Well)

NC VW19 (Groundwater UDI Surface Water-Well)

NC VW20 (Groundwater UDI Surface Water-Well)

NC VW21 (Groundwater UDI Surface Water-Well)

NC VW22 (Groundwater UDI Surface Water-Well)

NC VW23 (Groundwater UDI Surface Water-Well)

NC VW24 (Groundwater UDI Surface Water-Well)

NC VW25 (Groundwater UDI Surface Water-Well)

NC VW 26 (Groundwater UDI Surface Water-Well)

CC 1R (Groundwater UDI Surface Water-Well)

CC 2R (Groundwater UDI Surface Water-Well)

Potential Source(s) of Contamination:

CC 4R (Groundwater UDI Surface Water-Well)

CC 5R (Groundwater UDI Surface Water-Well)

CC SA6R (Groundwater UDI Surface Water-Well)

LFH1 (Groundwater-Well)

NC VW 19A (Groundwater UDI Surface Water-Well)

NC VW 10B (Groundwater UDI Surface Water-Well)

NC VW 11A (Groundwater UDI Surface Water-Well)

NC VW 12A (Groundwater UDI Surface Water-Well)

CC 3R (Groundwater UDI Surface Water-Well)

NC VW 18A (Groundwater UDI Surface Water-Well)

RAMPART SOUTH PLATTE RESERVIOR (Surface WaterIntake)

QUINCY RESERVIOR (Surface Water-Intake)

AURORA RESERVIOR (Surface Water-Intake)

DA1 WELL (Groundwater-Well)

DA2 WELL (Groundwater-Well)

DA3 WELL (Groundwater-Well)

NC VW 16A (Groundwater UDI Surface Water-Well)

EPA Abandoned Contaminated Sites, EPA Hazardous Waste Generators, EPA Chemical Inventory/Storage Sites, EPA Toxic Release Inventory Sites, Permitted Wastewater Discharge Sites, Aboveground, Underground and Leaking Storage Tank Sites, Solid Waste Sites, Existing/Abandoned Mine Sites, Other Facilities, Commercial/Industrial/Transportation, High Intensity Residential, Low Intensity Residential, Urban Recreational Grasses, Quarries / Strip Mines / Gravel Pits, Row Crops, Fallow, Small Grains, Pasture / Hay, Deciduous Forest, Evergreen Forest, Mixed Forest, Septic Systems, Oil / Gas Wells, Road Miles

Detected Contaminants

AURORA CITY OF routinely monitors for contaminants in your drinking water according to Federal and State laws. The following table(s) show all detections found in the period of January 1 to December 31, 2022 unless otherwise noted. The State of Colorado requires us to monitor for certain contaminants less than once per year because the concentrations of these contaminants are not expected to vary significantly from year to year, or the system is not considered vulnerable to this type of contamination. Therefore, some of our data, though representative, may be more than one year old. Violations and Formal Enforcement Actions, if any, are reported in the next section of this report. Note: Only detected contaminants sampled within the last five years appear in this report. If no tables appear in this section then no contaminants were detected in the last round of monitoring.

**If minimum ratio not met and no violation identified then the system achieved compliance using alternative criteria.

Unregulated Contaminants***

EPA has implemented the Unregulated Contaminant Monitoring Rule (UCMR) to collect data for contaminants suspected to be present in drinking water and do not have health-based standards set under the Safe Drinking Water Act. EPA uses results of UCMR monitoring to learn about the occurrence of unregulated contaminants in drinking water and to decide whether or not these comtaminants will be regulated in the future. We performed monitoring and reported analytical results to EPA in accordance with its UCMR. Once EPA reviews results, results are made available in the EPA’s National Contaminant Occurrence Database (NCOD) (epa.gov/dwucmr/national-contaminant-occurrence-database-ncod). Consumers can review results by accessing the NCOD. Contaminants detected during UCMR sampling and corresponding analytical results are provided below.

None reported.

***More information about the contaminants that were included in UCMR monitoring can be found at: drinktap.org/Water-Info/Whats-in-My-Water/UnregulatedContaminant-Monitoring-Rule-UCMR. Learn more about the EPA UCMR at: epa.gov/dwucmr/learn-about-unregulated-contaminant/monitoring-rule or contact the Safe Drinking Water Hotline at (800) 426-4791 or epa.gov/ground-water-and-drinking-water.

**Secondary standards are non-enforceable guidelines for contaminants that may cause cosmetic effects (such as skin or tooth discoloration) or aesthetic effects (such as taste, odor or color) in drinking water.

Non-health Based Violations

These violations do not usually mean there was a problem with the water quality. If there had been, we would have notified you immediately. We missed collecting a sample (water quality is unkown), we reported the sample result after the due date, or we did not complete a report/notice by the required date.

Additional Violation Information

Please share this information with all the other people who drink this water, especially those who may not have received this notice directly (for example, people in apartments, nursing homes, schools and businesses). You can do this by posting this notice in a public place or distributing copies by hand or mail.

Describe the steps taken to resolve the violation(s), and the anticipated resolution date:

Our water system violated a drinking water requirement in October of 2022. Although this situation is not a public health risk, as our customers you have a right to know what happened, what you should do, and what we ar edoing to correct the situation. We failed to timely report tampering of hydrants in the system. We notified CDPHE of the tampering, but we did not give the notification by 10 a.m. the next calendar day as required. There is nothing you need to do at this time. It has been determined that the tampering of the hydrants did not endanger public health. If a situation arises where the water is no longer safe to drink you will be notified within 24 hours.

We resolved the problem on Feb. 10, 2023. We have trained our staff to notify CDPHE of any future tampering of the water system by 10 a.m. the next calendar day. For more information, please contact Sherry Scaggiari at 303.739-7390, WaterRegulatory@auroragov.org or 15151 E.Alameda Parkway, Aurora, CO 80012.

Please share this information with all the other people who drink this water, especially those who may not have received this notice directly (for example, people in apartments, nursing homes, schools and businesses). You can do this by posting this notice in a public place or distributing copies by hand or mail.