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EWG's Tap Water Database — 2021 UPDATE

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Centennial Water and Sanitation District

EWG's drinking water quality report shows results of tests conducted by the water utility and provided to the Environmental Working Group by the Colorado Department of Public Health & Environment, as well as information from the U.S. EPA Enforcement and Compliance History database (ECHO). For the latest quarter assessed by the U.S. EPA (January 2021 - March 2021), tap water provided by this water utility was in compliance with federal health-based drinking water standards.

Utility Details

  • Douglas County, Colorado
  • Serves: 96,553
  • Data available: 2013-2020*
  • Source: Surface water
  • * 2013 testing is for chemicals in EPA's Third Unregulated Contaminant Monitoring Rule (UCMR-3) only. 2020/2021 testing is for chemicals in EPA's Fourth Unregulated Contaminant Monitoring Rule (UCMR-4) only.

Contaminants Detected

13

EXCEED
EWG HEALTH
GUIDELINES

27 Total Contaminants

  • Legal does not necessarily equal safe. Getting a passing grade from the federal government does not mean the water meets the latest health guidelines.
  • Legal limits for contaminants in tap water have not been updated in almost 20 years.
  • The best way to ensure clean tap water is to keep pollution out of source water in the first place.

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Contaminants Detected

Arsenic

Potential Effect: cancer234x EWG'S HEALTH GUIDELINE
THIS UTILITY0.938 ppb
EWG HEALTH GUIDELINE0.004 ppb
LEGAL LIMIT10 ppb
DETAILS
X

Arsenic is a potent carcinogen and common contaminant in drinking water. Arsenic causes thousands of cases of cancer each year in the U.S. Click here to read more about arsenic.

Arsenic was found at 234 times above EWG's Health Guideline.

EWG Health Guideline

0.004 ppb or less

This Utility

0.938 ppb

Legal Limit

10 ppb

National Average

0.647 ppb

State Average

0.159 ppb
The state and national averages were calculated using the averages of the contaminant measurements for each utility in 2017-2019.
ppb = parts per billion

Health Risks

The EWG Health Guideline of 0.004 ppb for arsenic was defined by the California Office of Environmental Health Hazard Assessment as a public health goal, the level of a drinking water contaminant that does not pose a significant health risk. This health guideline protects against cancer.

Pollution Sources

Agriculture

Industry

Naturally Occurring

Filtering Options

Reverse Osmosis

Ion Exchange

Bromodichloromethane

Potential Effect: cancer258x EWG'S HEALTH GUIDELINE
THIS UTILITY15.5 ppb
EWG HEALTH GUIDELINE0.06 ppb
NO LEGAL LIMIT
DETAILS
X

Bromodichloromethane

more about
this contaminant

Bromodichloromethane, one of the total trihalomethanes (TTHMs), is formed when chlorine or other disinfectants are used to treat drinking water. Bromodichloromethane and other disinfection byproducts increase the risk of cancer and may cause problems during pregnancy. Click here to read more about disinfection byproducts.

Bromodichloromethane was found at 258 times above EWG's Health Guideline.

EWG Health Guideline

0.06 ppb or less

This Utility

15.5 ppb

National Average

5.79 ppb

State Average

6.38 ppb
NO LEGAL LIMIT
The state and national averages were calculated using the averages of the contaminant measurements for each utility in 2017-2019.
ppb = parts per billion

Health Risks

The EWG Health Guideline of 0.06 ppb for bromodichloromethane was proposed in 2018 by the California Office of Environmental Health Hazard Assessment as a one-in-a-million lifetime risk of cancer. Values greater than one-in-a-million cancer risk level can result in increased cancer cases above one in a million people.

Pollution Sources

Treatment Byproducts

Filtering Options

Activated Carbon

Reverse Osmosis

Bromoform

Potential Effect: cancer12x EWG'S HEALTH GUIDELINE
THIS UTILITY6.24 ppb
EWG HEALTH GUIDELINE0.5 ppb
NO LEGAL LIMIT
DETAILS
X

Bromoform, one of the total trihalomethanes (TTHMs), is formed when chlorine or other disinfectants are used to treat drinking water. Bromoform and other disinfection byproducts increase the risk of cancer and may cause problems during pregnancy. Click here to read more about disinfection byproducts.

Bromoform was found at 12 times above EWG's Health Guideline.

EWG Health Guideline

0.5 ppb or less

This Utility

6.24 ppb

National Average

1.32 ppb

State Average

0.938 ppb
NO LEGAL LIMIT
The state and national averages were calculated using the averages of the contaminant measurements for each utility in 2017-2019.
ppb = parts per billion

Health Risks

The EWG Health Guideline of 0.5 ppb for bromoform was proposed in 2018 by the California Office of Environmental Health Hazard Assessment as a one-in-a-million lifetime risk of cancer. Values greater than one-in-a-million cancer risk level can result in increased cancer cases above one in a million people.

Pollution Sources

Treatment Byproducts

Filtering Options

Activated Carbon

Reverse Osmosis

Chloroform

Potential Effect: cancer17x EWG'S HEALTH GUIDELINE
THIS UTILITY6.89 ppb
EWG HEALTH GUIDELINE0.4 ppb
NO LEGAL LIMIT
DETAILS
X

Chloroform, one of the total trihalomethanes (TTHMs), is formed when chlorine or other disinfectants are used to treat drinking water. Chloroform and other disinfection byproducts increase the risk of cancer and may cause problems during pregnancy.

Chloroform was found at 17 times above EWG's Health Guideline.

EWG Health Guideline

0.4 ppb or less

This Utility

6.89 ppb

National Average

15.5 ppb

State Average

18.4 ppb
NO LEGAL LIMIT
The state and national averages were calculated using the averages of the contaminant measurements for each utility in 2017-2019.
ppb = parts per billion

Health Risks

The EWG Health Guideline of 0.4 ppb for chloroform was proposed in 2018 by the California Office of Environmental Health Hazard Assessment as a one-in-a-million lifetime risk of cancer. Values greater than one-in-a-million cancer risk level can result in increased cancer cases above one in a million people.

Pollution Sources

Treatment Byproducts

Filtering Options

Activated Carbon

Reverse Osmosis

Dibromoacetic acid

Potential Effect: 122x EWG'S HEALTH GUIDELINE
THIS UTILITY4.90 ppb
EWG HEALTH GUIDELINE0.04 ppb
NO LEGAL LIMIT
DETAILS
X

Dibromoacetic acid

more about
this contaminant

Dibromoacetic acid, one of the group of five haloacetic acids regulated by federal standards, is formed when chlorine or other disinfectants are used to treat drinking water. Haloacetic acids and other disinfection byproducts increase the risk of cancer and may cause problems during pregnancy. Click here to read more about disinfection byproducts.

Dibromoacetic acid was found at 122 times above EWG's Health Guideline.

EWG Health Guideline

0.04 ppb or less

This Utility

4.9 ppb

National Average

1.1 ppb

State Average

0.921 ppb
NO LEGAL LIMIT
The state and national averages were calculated using the averages of the contaminant measurements for each utility in 2017-2019.
ppb = parts per billion

Health Risks

The EWG Health Guideline of 0.04 ppb for dibromoacetic acid was defined in a peer-reviewed scientific study by EWG and represents a on-in-a-million lifetime cancer risk level. This health guideline protects against cancer.

Pollution Sources

Treatment Byproducts

Filtering Options

Activated Carbon

Reverse Osmosis

Dibromochloromethane

Potential Effect: cancer187x EWG'S HEALTH GUIDELINE
THIS UTILITY18.7 ppb
EWG HEALTH GUIDELINE0.1 ppb
NO LEGAL LIMIT
DETAILS
X

Dibromochloromethane

more about
this contaminant

Dibromochloromethane, one of the total trihalomethanes (TTHMs), is formed when chlorine or other disinfectants are used to treat drinking water. Dibromochloromethane and other disinfection byproducts increase the risk of cancer and may cause problems during pregnancy. Click here to read more about disinfection byproducts.

Dibromochloromethane was found at 187 times above EWG's Health Guideline.

EWG Health Guideline

0.1 ppb or less

This Utility

18.7 ppb

National Average

3.29 ppb

State Average

3.17 ppb
NO LEGAL LIMIT
The state and national averages were calculated using the averages of the contaminant measurements for each utility in 2017-2019.
ppb = parts per billion

Health Risks

The EWG Health Guideline of 0.1 ppb for dibromochloromethane was proposed in 2018 by the California Office of Environmental Health Hazard Assessment as a one-in-a-million lifetime risk of cancer. Values greater than one-in-a-million cancer risk level can result in increased cancer cases above one in a million people.

Pollution Sources

Treatment Byproducts

Filtering Options

Activated Carbon

Reverse Osmosis

Dichloroacetic acid

Potential Effect: cancer29x EWG'S HEALTH GUIDELINE
THIS UTILITY5.78 ppb
EWG HEALTH GUIDELINE0.2 ppb
NO LEGAL LIMIT
DETAILS
X

Dichloroacetic acid

more about
this contaminant

Dichloroacetic acid, one of the group of five haloacetic acids regulated by federal standards, is formed when chlorine or other disinfectants are used to treat drinking water. Haloacetic acids and other disinfection byproducts increase the risk of cancer and may cause problems during pregnancy. Click here to read more about disinfection byproducts.

Dichloroacetic acid was found at 29 times above EWG's Health Guideline.

EWG Health Guideline

0.2 ppb or less

This Utility

5.78 ppb

National Average

7.97 ppb

State Average

8.3 ppb
NO LEGAL LIMIT
The state and national averages were calculated using the averages of the contaminant measurements for each utility in 2017-2019.
ppb = parts per billion

Health Risks

The EWG Health Guideline of 0.2 ppb for dichloroacetic acid was proposed in 2020 by the California Office of Environmental Health Hazard Assessment as a public health goal, the level of a drinking water contaminant that does not pose a significant health risk.a one-in-a-million lifetime risk of cancer. Values greater than one-in-a-million cancer risk level can result in increased cancer cases above one in a million people.

Pollution Sources

Treatment Byproducts

Filtering Options

Activated Carbon

Reverse Osmosis

Haloacetic acids (HAA5)†

Potential Effect: cancer138x EWG'S HEALTH GUIDELINE
THIS UTILITY13.8 ppb
EWG HEALTH GUIDELINE0.1 ppb
LEGAL LIMIT60 ppb
DETAILS
X

Haloacetic acids (HAA5)

more about
this contaminant

Haloacetic acids are formed when disinfectants such as chlorine are added to tap water. The group of five haloacetic acids regulated by federal standards includes monochloroacetic acid, dichloroacetic acid, trichloroacetic acid, monobromoacetic acid and dibromoacetic acid.

Haloacetic acids (HAA5) was found at 138 times above EWG's Health Guideline.

EWG Health Guideline

0.1 ppb or less

This Utility

13.8 ppb

Legal Limit

60 ppb

National Average

17.1 ppb

State Average

18.5 ppb
The state and national averages were calculated using the averages of the contaminant measurements for each utility in 2017-2019.
ppb = parts per billion

Health Risks

The EWG Health Guideline of 0.1 ppb for the group of five haloacetic acids, or HAA5, was defined in a peer-reviewed scientific study by EWG and represents a one-in-a-million lifetime cancer risk level. This health guideline protects against cancer.

Pollution Sources

Treatment Byproducts

Filtering Options

Activated Carbon

Reverse Osmosis

Haloacetic acids (HAA9)†

Potential Effect: cancer446x EWG'S HEALTH GUIDELINE
THIS UTILITY26.8 ppb
EWG HEALTH GUIDELINE0.06 ppb
NO LEGAL LIMIT
DETAILS
X

Haloacetic acids (HAA9)

more about
this contaminant

Haloacetic acids are formed when disinfectants such as chlorine are added to tap water. The group of nine haloacetic acids includes monochloroacetic acid, dichloroacetic acid, trichloroacetic acid, monobromoacetic acid and dibromoacetic acid, which are regulated as a group by the federal government (HAA5); and bromochloroacetic acid, bromodichloroacetic acid, chlorodibromoacetic acid, and tribromoacetic acid.

Haloacetic acids (HAA9) was found at 446 times above EWG's Health Guideline.

EWG Health Guideline

0.06 ppb or less

This Utility

26.8 ppb

National Average

23.7 ppb

State Average

22.2 ppb
NO LEGAL LIMIT
The state and national averages were calculated using the averages of the contaminant measurements for each utility in 2017-2021.
ppb = parts per billion

Health Risks

The EWG Health Guideline of 0.06 ppb for the group of nine haloacetic acids, or HAA9, was defined in a peer-reviewed scientific study by EWG and represents a one-in-a-million lifetime cancer risk level as . This health guideline protects against cancer.

Pollution Sources

Treatment Byproducts

Filtering Options

Activated Carbon

Reverse Osmosis

Radium, combined (-226 & -228)

Potential Effect: cancer32x EWG'S HEALTH GUIDELINE
THIS UTILITY1.59 pCi/L
EWG HEALTH GUIDELINE0.05 pCi/L
LEGAL LIMIT5 pCi/L
DETAILS
X

Radium, combined (-226 & -228)

more about
this contaminant

Radium is a radioactive element that causes bone cancer and other cancers. It can occur naturally in groundwater, and oil and gas extraction activities such as hydraulic fracturing can elevate concentrations.

Radium, combined (-226 & -228) was found at 32 times above EWG's Health Guideline.

EWG Health Guideline

0.05 pCi/L or less

This Utility

1.59 pCi/L

Legal Limit

5 pCi/L

National Average

0.46 pCi/L

State Average

0.78 pCi/L
The state and national averages were calculated using the averages of the contaminant measurements for each utility in 2014-2019.
pCi/L = picocuries per liter

Health Risks

EWG applied the health guideline of 0.05 pCi/L, defined by the California Office of Environmental Health Hazard Assessment as a public health goal for radium-226, to radium-226 and radium-228 combined. This health guideline protects against cancer.

Pollution Sources

Industry

Naturally Occurring

Filtering Options

Reverse Osmosis

Ion Exchange

Total trihalomethanes (TTHMs)†

Potential Effect: cancer228x EWG'S HEALTH GUIDELINE
THIS UTILITY34.2 ppb
EWG HEALTH GUIDELINE0.15 ppb
LEGAL LIMIT80 ppb
DETAILS
X

Total trihalomethanes (TTHMs)

more about
this contaminant

Trihalomethanes are cancer-causing contaminants that form during water treatment with chlorine and other disinfectants. The total trihalomethanes group includes four chemicals: chloroform, bromodichloromethane, dibromochloromethane and bromoform.

Total trihalomethanes (TTHMs) was found at 228 times above EWG's Health Guideline.

EWG Health Guideline

0.15 ppb or less

This Utility

34.2 ppb

Legal Limit

80 ppb

National Average

29.7 ppb

State Average

29.1 ppb
The state and national averages were calculated using the averages of the contaminant measurements for each utility in 2017-2019.
ppb = parts per billion

Health Risks

The health guideline of 0.15 parts per billion, or ppb, for the group of four trihalomethanes, or THM4/TTHM, was defined in a peer-reviewed scientific study by EWG and represents a one-in-one-million lifetime cancer risk level.

Pollution Sources

Treatment Byproducts

Filtering Options

Activated Carbon

Reverse Osmosis

Trichloroacetic acid

Potential Effect: cancer27x EWG'S HEALTH GUIDELINE
THIS UTILITY2.72 ppb
EWG HEALTH GUIDELINE0.1 ppb
NO LEGAL LIMIT
DETAILS
X

Trichloroacetic acid

more about
this contaminant

Trichloroacetic acid, one of the group of five haloacetic acids regulated by federal standards, is formed when chlorine or other disinfectants are used to treat drinking water. Haloacetic acids and other disinfection byproducts increase the risk of cancer and may cause problems during pregnancy. Click here to read more about disinfection byproducts.

Trichloroacetic acid was found at 27 times above EWG's Health Guideline.

EWG Health Guideline

0.1 ppb or less

This Utility

2.72 ppb

National Average

6.62 ppb

State Average

7.54 ppb
NO LEGAL LIMIT
The state and national averages were calculated using the averages of the contaminant measurements for each utility in 2017-2019.
ppb = parts per billion

Health Risks

The EWG Health Guideline of 0.1 ppb for trichloroacetic acid was proposed in 2020 by the California Office of Environmental Health Hazard Assessment as a public health goal, the level of a drinking water contaminant that does not pose a significant health risk.a one-in-a-million lifetime risk of cancer. Values greater than one-in-a-million cancer risk level can result in increased cancer cases above one in a million people.

Pollution Sources

Treatment Byproducts

Filtering Options

Activated Carbon

Reverse Osmosis

Uranium

Potential Effect: cancer2.9x EWG'S HEALTH GUIDELINE
THIS UTILITY1.23 pCi/L
EWG HEALTH GUIDELINE0.43 pCi/L
LEGAL LIMIT20 pCi/L
DETAILS
X

Uranium is a known human carcinogen. The federal legal limit for uranium is set at 30 micrograms per liter (corresponding to parts per billion), but utilities can also report uranium in picocuries per liter (pCi/L), which is a measure of radioactivity in water. EWG translated all uranium results to pCi/L using a conversion factor developed by the EPA. With this conversion approach, the limit of 30 ppb corresponds to 20 pCi/L. Drinking water with this much uranium would cause more than 4.6 cancer cases in a population of 100,000. California set a public health goal for uranium of 0.43 pCi/L.

Uranium was found at 2.9 times above EWG's Health Guideline.

EWG Health Guideline

0.43 pCi/L or less

This Utility

1.23 pCi/L

Legal Limit

20 pCi/L

National Average

1.04 pCi/L

State Average

1.06 pCi/L
The state and national averages were calculated using the averages of the contaminant measurements for each utility in 2014-2019.
pCi/L = picocuries per liter

Health Risks

The EWG Health Guideline of 0.43 pCi/L for uranium was defined by the California Office of Environmental Health Hazard Assessment as a public health goal, the level of a drinking water contaminant that does not pose a significant health risk. Three most common uranium isotopes are U-234, U-235 and U-238. All isotopes of uranium are radioactive, and the total radioactivity depends on the ratio of isotopes. This health guideline protects against cancer.

Pollution Sources

Industry

Naturally Occurring

Filtering Options

Reverse Osmosis

Ion Exchange

Includes chemicals detected in 2017-2019 for which annual utility averages exceeded an EWG-selected health guideline established by a federal or state public health authority; chemicals detected under the EPA's Unregulated Contaminant Monitoring Rule (UCMR 4) program in 2017 to 2020 (and subsequent testing when available), for which annual utility averages exceeded a health guideline established by a federal or state public health authority; radiological contaminants detected between 2014 and 2019.

† HAA5 is a contaminant group that includes monochloroacetic acid, dichloroacetic acid, trichloroacetic acid, monobromoacetic acid and dibromoacetic acid. HAA9 is a contaminant group that includes the chemicals in HAA5 and bromochloroacetic acid, bromodichloroacetic acid, chlorodibromoacetic acid and tribromoacetic acid. TTHM is a contaminant group that includes bromodichloromethane, bromoform, chloroform and dibromochloromethane.


Other Contaminants Tested


Chemicals tested for but not detected from 2014 to 2019:

1,1,1-Trichloroethane , 1,1,2-Trichloroethane , 1,1-Dichloroethane , 1,1-Dichloroethylene , 1,2,3-Trichloropropane , 1,2,4-Trichlorobenzene , 1,2-Dibromo-3-chloropropane (DBCP) , 1,2-Dichloroethane , 1,2-Dichloropropane , 1,3-Butadiene , 1,4-Dioxane , 1-butanol , 2,3,7,8-TCDD (Dioxin) , 2,4,5-TP (Silvex) , 2,4-D , 2-methoxyethanol , 2-propen-1-ol , Alachlor (Lasso) , Aldicarb , Aldicarb sulfone , Aldicarb sulfoxide , Alpha-hexachlorocyclohexane , Antimony , Atrazine , Benzene , Benzo[a]pyrene , Beryllium , Bromochloromethane , Bromomethane , Butylated hydroxyanisole , Cadmium , Carbofuran , Carbon tetrachloride , Chlordane , Chlorodifluoromethane , Chloromethane , Chlorpyriphos , cis-1,2-Dichloroethylene , Cobalt , Dalapon , Di(2-ethylhexyl) adipate , Di(2-ethylhexyl) phthalate , Dichloromethane (methylene chloride) , Dimethipin , Dinoseb , Diquat , Endothall , Endrin , Ethoprop , Ethylbenzene , Ethylene dibromide , Germanium , Heptachlor , Heptachlor epoxide , Hexachlorobenzene (HCB) , Lindane , Mercury (inorganic) , Methoxychlor , Monochloroacetic acid , Monochlorobenzene (chlorobenzene) , Nitrite , o-Dichlorobenzene , o-toluidine , Oxamyl (Vydate) , Oxyflurofen , p-Dichlorobenzene , Pentachlorophenol , Perfluorobutane sulfonate (PFBS) , Perfluoroheptanoic acid (PFHPA) , Perfluorohexane sulfonate (PFHXS) , Perfluorononanoic acid (PFNA) , Perfluorooctane sulfonate (PFOS) , Perfluorooctanoic acid (PFOA) , Permethrin , Picloram , Polychlorinated biphenyls (PCBs) , Profenofos , Quinoline , Simazine , Styrene , Tebuconazole , Tetrachloroethylene (perchloroethylene) , Thallium , Toluene , Toxaphene , trans-1,2-Dichloroethylene , Tribufos , Trichloroethylene , Vinyl chloride , Xylenes (total)

Centennial Water and Sanitation District compliance with legally mandated federal standards:

  • From April 2019 to March 2021, Centennial Water and Sanitation District complied with health-based drinking water standards.
  • 2 QUARTERS
    in violation of any federal drinking water standard from April 2019 to March 2021

Information in this section on Centennial Water and Sanitation District comes from the U.S. EPA Enforcement and Compliance History Online database (ECHO).

LEARN MORE ABOUT THIS UTILITY

Water Filters That Can Reduce Contaminant Levels

ContaminantActivated Carbonactivated carbonReverse Osmosisreverse osmosisIon Exchangeion exchange
CONTAMINANTS ABOVE
HEALTH GUIDELINES
Arsenic
Bromodichloromethane
Bromoform
Chloroform
Dibromoacetic acid
Dibromochloromethane
Dichloroacetic acid
Haloacetic acids (HAA5)
Haloacetic acids (HAA9)
Radium, combined (-226 & -228)
Total trihalomethanes (TTHMs)
Trichloroacetic acid
Uranium, combined (pCi/L)
OTHER CONTAMINANTS
DETECTED
Barium
Chlorate
Chromium (hexavalent)
Chromium (total)
Fluoride
Hexachlorocyclopentadiene
Manganese
Molybdenum
Monobromoacetic acid
Nitrate
Nitrate & nitrite
Selenium
Strontium
Vanadium

Take Action

Contact Your Local Official

One of the best ways to push for cleaner water is to hold accountable the elected officials who have a say in water quality – from city hall and the state legislature to Congress all the way to the Oval Office – by asking questions and demanding answers.

LEARN MORE

Filter Out Contaminants

Check out our recommendations for filters to protect your water against the detected contaminants.

EWG’S WATER FILTER GUIDE