2020

INFORME DE CALIDAD DE AGUA

Photo credit: iStock. Denver Water’s Public Water System Identification: CO0116001 3,10 0 square miles of watersheds

5 mountain

3,000 miles of pipe to carry water

Photo credit: iStock. WHAT IS THIS REPORT? The Environmental Protection Agency a source water assessment of the For more information on the report, requires public water suppliers that potential for contaminants reaching contact the Colorado Department serve the same people year-round any of Denver Water’s three terminal of Public Health and Environment (community water systems) to provide reservoirs at Strontia Springs, Marston by calling 303-692-2000 or visit consumer confidence reports to their and Ralston, the last stop for the water Colorado.gov/cdphe/ccr. The report customers. These reports are also before it is treated. The potential is located under “Guidance: Source known as annual reports. sources of that may exist Water Assessment Reports.” Search This report summarizes information are: EPA areas of concern; permitted the table using 116001 Denver Water regarding water sources used, any wastewater discharge sites; above Board. Or call Denver Water Customer detected contaminants, compliance ground, underground and leaking Care at 303-893-2444. and educational information. storage tank sites; solid waste sites; Información importante Where does your existing or abandoned mine sites; other acerca de la calidad del agua water come from? facilities; commercial, industrial and Para recibir la versión en español del transportation activities; residential, Denver’s Informe de Calidad de Agua de 2020 de urban recreational grasses; quarries, comes from , , Denver Water, llame a Servicio strip mines and gravel pits; agriculture; streams, reservoirs and al cliente al 303-893-2444 o visite forests; septic systems; oil and gas springs fed by high-quality mountain denverwater.org/CalidadDeAgua. wells; and roads. snow runoff. Denver Water’s supply is 100% surface water that originates in sources throughout 3,100 square miles of watersheds on both sides of the Continental Divide. Mountain water sources Denver Water’s water sources are the South Platte and its tributaries, the streams that feed Dillon , and the creeks and canals above the Fraser River. Denver Water stores its water in five mountain reservoirs: Antero, Eleven Mile Canyon, Cheesman, Dillon and Gross. From these reservoirs, the water is then sent to the metro area through a complex system of streams, canals and pipes. After treatment, drinking water is fed by both gravity and pumps to a system of underground, clean-water reservoirs before continuing to your home or business. More than 3,000 miles of pipe carry water to Denver Water customers. Source water assessment The Colorado Department of Public Health and Environment has completed

1 | 2020 Water Quality Report | SOURCES OF DRINKING WATER DENVER WATER’S SYSTEM Devoted to water quality Denver Water proudly serves high-quality water to 1.5 million people in the city of Denver and many surrounding suburbs. Since 1918, we have expertly planned, developed and operated a complex system that provides clean, safe, great-tasting water. Denver Water is a public agency funded by water rates, new tap

Photo credit: iStock. fees and the sale of hydropower, not taxes. We are Colorado’s oldest and largest water utility — Denver Water has a total water Sources of drinking water include rivers, service area of approximately 300 square miles. lakes, streams, ponds, reservoirs, springs and Denver Water serves 25% of the state’s population with less than wells. As water travels over the surface of 2% of all the water used in the state. The natural environment is the land or through the ground, it dissolves our lifeline, and we help protect it by promoting wise water use. naturally occurring and, in some We take our water quality very seriously. Last year, we collected cases, radioactive material. It can also pick up more than 35,000 samples and conducted more than 70,000 substances resulting from human activity and tests to ensure our water is as clean and safe as possible. Denver Water vigilantly safeguards our mountain water supplies, and the presence of animals. Contaminants may the water is carefully treated before it reaches your tap. This include the following: brochure provides data collected throughout 2019. Microbial contaminants , and other microbes that may come from sewage treatment plants, Reservoir Capacity Percent of septic systems, agricultural livestock (acre-feet) Total Capacity operations and wildlife. Dillon 257,304 37.1 Inorganic contaminants Eleven Mile Canyon 97,779 14.1 and metals, which can be naturally Williams Fork 96,822 14.0 occurring or result from urban stormwater Cheesman 79,064 11.4 runoff, industrial or domestic wastewater discharges, oil and gas production, mining Gross 41,811 6.0 or farming. Chatfield 27,076 4.0 and herbicides (Denver's portion) Wolford Mountain Chemical substances resulting from a variety 25,610 3.7 of sources, such as agricultural and urban (Denver's portion) stormwater runoff, and residential uses. Antero 19,881 2.9 Organic chemical contaminants Marston 19,796 2.9 Substances including synthetic and volatile Ralston 10,776 1.5 organic chemicals, which are byproducts Strontia Springs 7,863 1.1 of industrial processes and petroleum production, that may come from gas stations, Meadow Creek 5,370 0.8 urban stormwater runoff and septic systems. Long Lakes 1,787 0.3 Radioactive contaminants Platte Canyon 910 0.1 Substances that can be naturally occurring or Soda Lakes 645 0.1 be the result of oil and gas production, and mining activities. Total 692,846 100

2 | 2020 Water Quality Report | Photo credit: Denver Water.

WATER AT A GLANCE All drinking water, including bottled undergone organ transplants, people lead solder connecting copper pipes water, may reasonably be expected with HIV/AIDS or other immune in their plumbing. Faucets and fixtures to contain at least small amounts of system disorders, some elderly and made before 2014 do not meet today’s some contaminants. The presence of infants, can be particularly at risk of “lead-free” requirements. . These people should seek contaminants does not necessarily Lead exposure can cause serious health advice about drinking water from their indicate that the water poses a health problems, especially for pregnant health care providers. Guidelines from risk. In order to ensure that tap water is women and young children. safe to drink, the Colorado Department the EPA and the Centers for of Public Health and Environment’s Control and Prevention on appropriate To address this issue, Denver Water has regulations set limits on the amount of means to lessen the risk of by launched the Lead Reduction Program, certain contaminants in water provided cryptosporidium and other microbial which was approved in December 2019 by public water systems. The Food contaminants are available from the Safe by the EPA and Colorado Department of and Drug Administration sets limits for Drinking Water Hotline, 800-426-4791. Public Health and Environment. contaminants in bottled water to provide Lead in drinking water The Lead Reduction Program similar protection for public health. Denver Water is committed to delivering has five main components: More information about contaminants safe water to our customers. The water • Increasing the pH level of the water and potential health effects can be we provide to homes and businesses to reduce the risk of lead from obtained by calling the EPA’s Safe is lead-free, but lead can get into the getting into drinking water from Drinking Water Hotline at 800-426-4791 water as it moves through customer- lead service lines or household or by visiting epa.gov/ground-water- owned water service lines and household plumbing. This change is being and-drinking-water. plumbing that contain lead. done to reduce the corrosivity of Some people may be more vulnerable Service lines bring water into a home the water, which will help protect to contaminants in drinking water or building from Denver Water’s main customers who have plumbing in than the general population. delivery pipe in the street. In Denver their home that contains lead, such Immunocompromised people, such Water’s experience, homes built prior to as customer-owned water service as people with cancer undergoing 1951 are more likely to have lead service lines that connect their home to chemotherapy, people who have lines. Homes built before 1987 may have Denver Water’s main delivery pipe

3 | 2020 Water Quality Report | in the street, solder that connects to minimize the risk of testing and steps to minimize exposure sections of pipe in their home, and lead getting into drinking water from is available from the Safe Drinking faucet parts. lead pipes and plumbing. Denver Water Water Hotline at 1-800-426-4791, studied multiple treatment options from at and at • Developing and maintaining a epa.gov/safewater/lead 2012 to 2017. Based on the results, . publicly accessible inventory of all denverwater.org/Lead the Colorado Department of Public customer-owned lead service lines Lead may exist in other areas of your Health and Environment in March 2018 in Denver Water’s service area. home. For a complete list and more required Denver Water to begin adding This interactive map is available at information, visit colorado.gov/cdphe/ orthophosphate to the water it delivers denverwater.org/Lead. lead-what-are-common-sources. in March 2020. • Replacing all lead service lines Orthophosphate is a food additive over 15 years at no direct charge commonly added to water to minimize Is there a presence of to the customer. corrosion and reduce the amount of lead cryptosporidium and giardia? • Providing a free water pitcher and released from pipes and fixtures. It has Denver Water has tested for filters that are certified to remove been safely and successfully used across cryptosporidium (crypto) and giardia in lead to all customers suspected of the country. Orthophosphate can impact both source and treated water since the having a lead service line, for use plants and the 1980s. Since that time, Denver Water until six months after their service downstream environment. has never detected a viable indication of line is replaced. either in the drinking water. Denver Water proposed a holistic, • Ongoing communication, outreach alternative approach to orthophosphate Crypto and giardia are microscopic and education. that removes lead at its source. The organisms that, when ingested, can cause diarrhea, cramps, fever and other How the program came to be approach focuses on replacing all gastro-intestinal symptoms. Crypto and Since 1992, as part of the EPA’s Lead lead service lines in the service area giardia are usually spread through means and Copper Rule, Denver Water has and avoids the potential impacts of other than drinking water. monitored water quality in homes that orthophosphate to wastewater treatment have lead service lines or plumbing that plants and downstream reservoirs, While most people readily recover from contains lead. streams and rivers. the symptoms, crypto and giardia can cause more serious illness in people with In 2012, water quality sample results That proposal became the Lead compromised immune systems. The from homes with known lead service Reduction Program, which is organisms are in many of Colorado’s rivers lines and plumbing exceeded the level now underway. Learn more about and streams and are a result of animal the EPA requires for taking action. The this effort and the program at wastes in the watershed. At the treatment action level is an indicator that additional denverwater.org/Lead. plants, Denver Water removes crypto and steps may need to be taken to “optimize If you are concerned about lead, you giardia through effective filtration, and corrosion control treatment.” That can request to have your water tested. giardia is also killed by disinfection. means a utility may need to adjust its Information on lead in drinking water,

Filter HOW TO MINIMIZE YOUR Use filtered water for drinking (including making EXPOSURE TO LEAD tea and coffee), cooking (particularly when making foods like rice, beans and soup) and Flush If water has not been used in the home for a few preparing infant formula. Be sure the filter is NSF hours, such as first thing in the morning or when certified to remove lead. Visitnsf.org for getting home from work, run the kitchen or any filter options. bathroom faucet for five minutes. You also can run Maintain the dishwasher, take a shower, or do a load of laundry to Regularly clean your faucet’s screen, also known as help flush water in your home’s plumbing before drinking an aerator. You can find an instructional video at or cooking. denverwater.org/Lead. Use only cold water for drinking, cooking and making Replace filters at the manufacturer’s recommended infant formula. Boiling the water does not remove lead. schedule.

20192020 Water QualityQuality Report Report | | 5 4 | 2020 Water Quality Report | WATER QUALITY MONITORING VIOLATION THE TREATMENT Findings from the Colorado Department of Public Health and Environment’s 2019 Sanitary Survey resulted in notification to Denver Water on Sept. 19, 2019, of two violations of Regulation 11. PROCESS The treatment process consists What happened? of five steps: Regarding the first violation, inspectors noted that Denver Water regularly conducts tank COAGULATION/ inspections and has some written standard operating procedures regarding its storage tank inspections. However, Denver Water's standard operating procedures were not Raw1 water is drawn into mixing comprehensive enough to meet all the state's requirements for storage tank inspections. The basins at our treatment plants incomplete procedures did not allow Denver Water to successfully and consistently implement where we add alum and polymer. its storage tank inspection plan for all its storage tanks. This process causes small In the second violation, Denver Water was monitoring and reporting the combined filter effluent to stick to one another, for the Foothills Water Treatment Plant using a sample line from the treatment plant’s forming larger particles. clear well. However, Denver Water should have been reporting the combined filter effluent turbidity from our monitoring location nearer to the combined filter effluent. Turbidity values at each of these locations were similar, but this reporting error violates drinking water requirements. Over2 time, the now larger How did this impact water quality? particles become heavy enough Denver Water monitors water quality throughout the Denver-metro area 24/7/365, to ensure to settle to the bottom of a basin the water meets drinking water standards, which verifies that the drinking water system was from which is removed. not compromised as a result of these violations. FILTRATION What is being done (corrective action)? The3 water is then filtered Your water is safe to drink, and water quality was never compromised. With regard to the first through layers of fine, granulated violation, Denver Water is updating its storage tank inspection plan this year to reflect the materials — either sand, or recommendations made by the health department. The second violation was corrected in sand and coal, depending on 2019 by switching sample sites per health department recommendations. the treatment plant. As smaller, For more information, contact Denver Water Customer Care at 303-893-2444. You can read more suspended particles are removed, about our extensive treatment process at denverwaterTAP.org. turbidity diminishes and clear Please share this information with all other people who drink this water, especially those water emerges. 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 public places or by 4 DISINFECTION distributing copies by hand. As protection against any bacteria, viruses and other Technical description of violations microbes that might remain, 1. F330 — Management: is added before the Storage Tank Inspection Plan (T3): Supplier has not developed or maintained a finished water water flows into underground storage tank inspection plan. This is a violation of Regulation 11, Section 11.28(4)(a). reservoirs throughout the At the time of the sanitary survey, the department found that the supplier appears to regularly distribution system and into conduct tank inspections and has some written standard operating procedures (SOPs) regarding your home or business. Denver its storage tank inspections. However, the supplier’s SOPs are not comprehensive and complete Water carefully monitors the to meet all the required elements of the written plan for storage tank inspections as specified amount of disinfectant added in Section 11.28(2) of Regulation 11 and to allow the supplier to successfully and consistently to maintain quality of the water implement its storage tank inspection plan for all its storage tanks. at the farthest reaches of the 2. R529 — Monitoring, Recordkeeping and Data Verification: system. Fluoride occurs naturally Monitoring Turbidity (T3): Supplier was not properly monitoring and/or recording turbidity in our water but is also added to values. This is a violation of Regulation 11, Section 11.8(1)(2). treated water, when needed, to achieve public health levels. At the time of the sanitary survey, the supplier was monitoring and reporting the combined filter effluent (CFE) turbidity for the Foothills Water Treatment Plant using a sample line from the treatment plant’s clear well. However, the supplier has the ability to monitor CFE turbidity at a CORROSION common header for all individual filter effluents prior to entering the clear well. CONTROL pH5 is maintained by adding These violations do not pose a safety risk to customers and do not require consumers to alkaline substances to reduce take action, but you have a right to know what happened and what we have done to correct corrosion in the distribution this situation. system and the plumbing in your home or business. 5 | 2020 Water Quality Report | REGULATED WATER CONTAMINANTS: WHAT IS IN THE WATER? Data collected throughout 2019

Inorganic Contaminants Sampled at the Entry Point to the Distribution System Chemical Sampling Unit of MCL Year Average Range MCL MCLG Typical Sources Parameters Frequency Measure Violation Discharge from petroleum refineries, fire Antimony 2019 Monthly BRL BRL ppb 6 6 No retardants, ceramics, electronics, solder. of natural deposits, runoff from Arsenic 2019 Monthly BRL BRL ppb 10 0 No orchards, runoff from glass and electronics, solder. Erosion of natural deposits, discharge of Barium 2019 Monthly 30.7 16.7-50.0 ppb 2000 2000 No drilling wastes. Discharge from metal refineries and coal- Beryllium 2019 Monthly BRL BRL ppb 4 4 No burning factories; discharge from electrical, aerospace, and defense industries. Corrosion of galvanized pipes, erosion of natural deposits, discharge from metal Cadmium 2019 Monthly BRL BRL ppb 5 5 No refineries, runoff from waste batteries and paints. Discharge from steel and pulp mills, Chromium 2019 Monthly BRL BRL ppb 100 100 No erosion of natural deposits. Copper 2019 Monthly 0.79 BRL-2.3 ppb 1300 (AL) 1300 No Erosion of natural deposits. Erosion of natural deposits; discharge Mercury 2019 Monthly BRL BRL ppb 2 2 No from refineries and factories; runoff from landfills and croplands. Discharge from petroleum and metal Selenium 2019 Monthly BRL BRL ppb 50 50 No refineries; erosion of natural deposits; discharge from mines. Erosion of natural deposits; discharge Thallium 2019 Monthly BRL BRL ppb 2 0.5 No from refineries and factories; runoff from landfills and croplands. Uranium 2019 Monthly BRL BRL ppb 30 zero No Erosion of natural deposits, mine drainage. Erosion of natural deposits, water additive 4.0 (2.0 is Fluoride 2019 Monthly 0.54 0.13-0.76 ppm 4 No that promotes strong teeth, discharge from SMCL) fertilizer and aluminum factories. Runoff from fertilizer use; leaching Nitrate as N 2019 Monthly 0.02 BRL-0.13 ppm 10 10 No from septic tanks, sewage; erosion of natural deposits. Runoff from fertilizer use; leaching Nitrite as N 2019 Monthly BRL BRL ppm 1 1 No from septic tanks, sewage; erosion of natural deposits. Annually 2,4-D 2019 (Foothills BRL BRL ppb 70 70 No Runoff from herbicide used on row crops. WTP)

TERMS, ABBREVIATIONS, AND SYMBOLS Some of the terms, abbreviation and symbols are unique to the water industry and might not be familiar to all customers. Terms used in the table are explained below.

Action Level (AL) Level 1 Assessment Maximum Residual Disinfection Level (MRDL) Picocuries per liter (pCi/L) The concentration of a contaminant, which A study of the water system to identify potential The highest level of a disinfection allowed in Measure of the radio activity in water. if exceeded, triggers treatment or other problems and determine (if possible) why drinking water. There is convincing evidence that Range requirements that a water system must total coliform bacteria have been found in our addition of a disinfection is necessary for control of The lowest value to the highest value. comply with. water system. microbial contaminants Running Annual Average (RAA) Average Level 2 Assessment Maximum Residual Disinfection Level Goal (MRDLG) The average of sample results for samples Typical Value A very detailed study of the water system to identify The level of a drinking water disinfectant, below which collected during the most recent four potential problems and determine (if possible) why there is no known or expected risk to health. MRDLGs Below Reporting Level (BRL) Below the calendar quarters. an E. coli MCL violation has occurred and/or why do not reflect the benefits of the use of reportable level for an analysis or below the total coliform bacteria have been found in our water to control microbial contaminants. Secondary Maximum Contaminant Level (SMCL) lowest reliable level that can be measured. system on multiple occasions. Nonenforceable, recommended limits for Nephelometric Turbidity Unit (NTU) Compliance Value substances that may affect the taste, odor, color or The Measure of the clarity or cloudiness of water. Single or calculated value used to determine if a Locational Running Annual Average (LRAA) other aesthetic qualities of drinking water. average of sample results for samples collected at Turbidity in excess of 5 NTU is just noticeable to the regulatory contaminant level is met. Examples a monitoring location during the most recent four typical person. Treatment Technique of calculated values are the Average, 90th calendar quarters. A required process intended to reduce the level of Percentile, Running Annual Average, Location Non-Health-Based a contaminant in drinking water. Running Annual Average. Maximum Contaminant Level (MCL) A violation that is not an MCL or TT. Maximum level of a contaminant allowed in Variance and Exemptions Contaminant Not Applicable (N/A) drinking water. Department permission not to meet an MCL or TT A potentially harmful biological, chemical, or Does not apply or not available. under certain conditions. radiological substance. Maximum Contaminant Level Goal (MCLG) The Parts per billion = Micrograms per liter (ppb = µg/L) level of a contaminant in drinking water below which Violation Formal Enforcement Action Escalated action Equivalent to micrograms per liter. One ppb is there is no known or expected risk to health. MCLGs Failure to meet a Colorado Primary Drinking taken by the stat to bring a noncompliant water comparable to one drop of water in 55,000 gallons. allow for a margin of safety. Water regulation. system back into compliance. Parts per million = Milligram per liter (ppm = mg/L) Water Treatment Plant (WTP) Equivalent to milligrams per liter. One ppm is Health-Based Water Treatment Plant Violation of either an MCL or TT. comparable to one drop of water in 55 gallons.

6 | 2020 Water Quality Report | REGULATED WATER CONTAMINANTS: WHAT IS IN THE WATER? Secondary Contaminants Sampled at the Entry Point to the Distribution System* Chemical Sampling Unit of MCL Year Average Range MCL MCLG Typical Sources Parameters Frequency Measure Violation Erosion of natural deposits, water Aluminum 2019 Monthly 24.3 10.9-40.4 ppb 50 - 200 (SMCL) N/A No treatment chemical. Sodium 2019 Monthly 14.8 5.1-24.7 ppm N/A N/A No Naturally occurring

*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.

Summary of Turbidity Sampled at the Entry Point to the Distribution System Chemical Sampling Unit of Treatment Technique Treatment Technique Typical Year Level Found Parameters Frequency Measure Requirement Violation Sources Highest single measurement: 0.135 Maximum 1 NTU for any one Turbidity 2019 Daily NTU No Soil runoff NTU (March, Moffat Treatment Plant) single measurement. Lowest monthly percentage of In any month, at least 95% of Turbidity 2019 Daily samples meeting TT requirement for NTU samples must be less than No Soil runoff our technology: 100% 0.3 NTU.

Turbidity has no health effects. However, turbidity can interfere with disinfection and provide a medium for microbial growth. Turbidity may indicate the presence of disease-causing organisms. These organisms include bacteria, viruses, and parasites that can cause symptoms such as nausea, cramps, diarrhea, and associated headaches.

Total Organic Carbon (Disinfection Byproducts Precursor) Removal Ratio of Raw and Finished Water* Chemical Treatment Technique Year Frequency Treatment Technique Requirement Typical Sources Parameters Violation **Denver Water uses enhanced treatment to remove Total organic Twice per Natural organic matter present in the required amount of natural organic material and/or No carbon ratio 2019 month the environment. demonstrates compliance with alternative criteria. **Total organic carbon (TOC) has no health effects. However, total organic carbon provides a medium for the formation of disinfection byproducts including trihalomethanes (TTHMs) and haloacetic acids (HAA5s). Drinking water containing these byproducts in excess of the MCL may lead to adverse health effects, liver or kidney problems, or nervous system effects, and may lead to an increased risk of getting cancer.

Disinfection Byproducts Sampled in the Distribution System Sampling Highest Unit of MCL Name Year Range MCL MCLG Typical Sources Frequency Locational RAA Measure Violation Byproduct of drinking Total Trihalomethanes (TTHM) 2019 Monthly 24.6 11.9-33.1 ppb 80 N/A No water disinfection. Byproduct of drinking Haloacetic Acids (HAA5s) 2019 Monthly 15 7.5-22.9 ppb 60 N/A No water disinfection.

Microbial Contaminants Regulated in the Distribution System Sampling Unit of Highest Monthly MCL Name Year MCL MCLG Number of Positives Typical Sources Frequency Measure Percentage Violation Total Coliform 2019 Daily No more than 5% Zero Present/ 0.5% (present T. 2 out of 4,524 total No Naturally (T. coli) positive per month Absent coli), July 2019 samples present in the (0.04%); 0 E. coli environment. positive samples

Disinfectants Sampled in the Distribution System* Number of Samples Treatment Technique Name Year Results Frequency MRDL Typical Sources Below Level Violation Disinfectant 2019 Lowest period percentage 0 Daily No Drinking water as Total Cl2 of samples above 0.2 ppm: 4.0 ppm disinfectant used to 100% control microbial growth *Treatment technique requirement: at least 95% of samples per period (month or quarter) must be at least 0.2 ppm

Lead and Copper Sampled in the Distribution System Contaminant Period 90th Sample Unit of 90th Percentile Sample Sites Above 90th Percentile Typical Sources Name Percentile Size Measure Action Level Action Limit AL Exceedance Corrosion of household plumbing; erosion Copper 1-6/2019 0.31 614 ppm 1.3 2 No of natural deposits. Corrosion of household plumbing; erosion Lead 1-6/2019 10 614 ppb 15 26 No of natural deposits. Corrosion of household plumbing; erosion Copper 7-12/2019 0.25 753 ppm 1.3 1 No of natural deposits. Corrosion of household plumbing; erosion Lead 7-12/2019 11.7 753 ppb 15 48 No of natural deposits.

7 | 2020 Water Quality Report | TESTING FOR UNREGULATED CONTAMINANTS Since 1996, the EPA, through its Unregulated Contaminant The American Water Works Association has more information Monitoring Rule, every five years requires water utilities across about the rule and the process on its website: the country to test for a list of substances that are suspected of drinktap.org/water-info/whats-in-my-water/unregulated- being in drinking water but are not currently regulated under contaminant-monitoring-rule-ucmr. Information the Safe Drinking Water Act. Utilities report their test results to about the rule also can be found on the EPA’s the EPA, which uses the information to learn more about the website at epa.gov/dwucmr/learn-about- presence of these substances and decide whether they should unregulated-contaminant-monitoring-rule or be regulated in the future to protect public health. you can contact the Safe Drinking Water Hotline at or . Denver Water’s 2019 test results were reported to the EPA as 800-426-4791 water.epa.gov/drink/contact.cfm required. Below are the substances that were detected during Denver Water’s tests and the levels at which they were found.

Unregulated Contaminants Monitoring Rule 4

Units of Chemical Parameters Year Sample site Average Range measure

Bromochloroacetic acid (BCAA) 2019 Distribution System 2.45 0.75-3.69 ppb

Bromodichloroacetic acid (BDCAA) 2019 Distribution System 1.57 0.74-2.25 ppb

Chlorodibromoacetic acid (CDBAA) 2019 Distribution System 0.33 BRL-0.67 ppb

Tribromoacetic acid (TBAA) 2019 Distribution System BRL BRL ppb

1-butanol 2019 Treatment Plant Treated Water BRL BRL ppb

2-methoxyethanol 2019 Treatment Plant Treated Water BRL BRL ppb

2-propen-1-ol 2019 Treatment Plant Treated Water BRL BRL ppb a-hexachlorocyclohexane 2019 Treatment Plant Treated Water BRL BRL ppb

Butylated hydroxyanisole 2019 Treatment Plant Treated Water BRL BRL ppb

Chloropyrifos 2019 Treatment Plant Treated Water BRL BRL ppb

Dimenthipin 2019 Treatment Plant Treated Water BRL BRL ppb

Ethoprop 2019 Treatment Plant Treated Water BRL BRL ppb

Germanium 2019 Treatment Plant Treated Water BRL BRL ppb

Manganese 2019 Treatment Plant Treated Water 4.88 BRL-26 ppb o-toluidine 2019 Treatment Plant Treated Water BRL BRL ppb

Oxyfluorfen 2019 Treatment Plant Treated Water BRL BRL ppb

Profenofos 2019 Treatment Plant Treated Water BRL BRL ppb

Quinoline 2019 Treatment Plant Treated Water BRL BRL ppb

Tebuconazole 2019 Treatment Plant Treated Water BRL BRL ppb

Total permethrin (cis- & trans-) 2019 Treatment Plant Treated Water BRL BRL ppb

Tribufos 2019 Treatment Plant Treated Water BRL BRL ppb

Treatment Plant Source Water (raw Bromide 2019 BRL BRL-0.05 ppm water) Treatment Plant Source Water (raw Total Organic Carbon (TOC) 2019 2.98 2.13-4.6 ppm water)

8 | 2020 Water Quality Report | Photo credit: iStock. 1600 W. 12th Ave., Denver, CO 80204-3412 303-893-2444

For more information on water quality, including opportunities for public participation, visit denverwater.org.

@DenverWater @Denver_Water DenverWater YourDenverWater denverwaterTAP.org

Denver Water’s Public Water System Identification: CO0116001

Photo credit: iStock.