250 systems serving 785,973 people
  This drinking water quality report shows results of tests conducted by water utilities in South Dakota, provided to the Environmental Working Group (EWG) by the South Dakota Department of Environment & Natural Resources. It is part of EWG's national database that includes 47,667 drinking water utilities and 20 million test results from 45 states and the District of Columbia. Water utilities nationwide detected more than 300 pollutants between 2004 and 2009. More than half of these chemicals are unregulated, legal in any amount. Despite this widespread contamination, the federal government invests few resources in protecting rivers, reservoirs, and groundwater from pollution in the first place. The information below summarizes drinking water quality for this state.

Water Utilities
Population Served
Detected Chemicals
Exceed health guidelines*
Exceed Legal Limits*
Unregulated chemicals detected
* Water utilities are noted as exceeding the legal limit if any test is above the maximum contaminant level (MCL). Most MCLs are based on annual averages so exceeding the MCL for one test does not necessarily indicate that the system is out of compliance.

  15 Contaminants Exceeding Health Based Limits

Contaminants detected in South Dakota drinking water above health guidelines, according to an Environmental Working Group analysis of data obtained from state water authorities.

Number of Systems
At Any Level Above Health Limits At Any Level Above Health Limits
Arsenic (total) 398,179 398,179 78 78
Alpha particle activity (excl radon and uranium) 216,113 216,113 97 97
Radium-226 109,997 109,997 36 36
Radium-228 104,998 104,998 37 37
Total trihalomethanes (TTHMs) 33,068 32,463 10 9
Total haloacetic acids (HAAs) 32,463 32,463 9 9
Trichloroethylene 13,876 13,876 1 1
Mercury (total inorganic) 3,798 876 7 1
1,2-Dichloroethane 775 775 1 1
Nitrate 454,213 387 176 2

  Sources of South Dakota Drinking Water Contaminants

The contaminants identified in South Dakota drinking water come from a wide variety of sources, including agriculture, industry, water treatment plants, and polluted storm runoff from urban areas.

26 Total Contaminants Detected (2004 - 2009)
6 Agricultural Pollutants
(pesticides, fertilizer, factory farms)

Arsenic (total), Nitrate, Nitrite, Selenium (total), 2,4,5-TP (Silvex), Ethylbenzene

11 Sprawl and Urban Pollutants
(road runoff, lawn pesticides, human waste)

Arsenic (total), Cadmium (total), Mercury (total inorganic), Nitrate, Nitrite, Antimony (total), 2,4,5-TP (Silvex), p-Xylene, Tetrachloroethylene, m-Xylene, o-Xylene

22 Industrial Pollutants

Arsenic (total), Barium (total), Cadmium (total), Chromium (total), Mercury (total inorganic), Nitrate, Nitrite, Selenium (total), Antimony (total), Thallium (total), Di(2-ethylhexyl) phthalate, p-Xylene, 1,2-Dichloroethane, Trichloroethylene, Tetrachloroethylene, Ethylbenzene, m-Xylene, o-Xylene, Alpha particle activity (excl radon and uranium), Radium-226, Radium-228, Combined Uranium (pCi/L)

4 Water Treatment and Distribution Byproducts
(pipes and fixtures, treatment chemicals and byproducts)

Cadmium (total), Di(2-ethylhexyl) phthalate, Total haloacetic acids (HAAs), Total trihalomethanes (TTHMs)

12 Naturally Occurring
(naturally present but increased for lands denuded by sprawl, agriculture, or industrial development)

Arsenic (total), Barium (total), Chromium (total), Mercury (total inorganic), Nitrate, Nitrite, Selenium (total), Alpha particle activity (excl radon and uranium), Radon, Radium-226, Radium-228, Combined Uranium (pCi/L)

1 Unregulated Contaminants
EPA has not established a maximum legal limit in tapwater for these contaminants


  Testing Summary for South Dakota

The federal government has set standards for some of the pollutants found in tap water supplies.

Contaminants reported as tested by water suppliers in South Dakota 85
  Contaminants tested due to federal law: 73
  Contaminants tested in addition to those required by federal law: 12
  Violation Summary for South Dakota

Data from the U.S. Environmental Protection Agency includes the following violations of federal standards in South Dakota since 2004.

Violation Type Number of Violations
Failure to monitor regularly 1,715
Over maximum contaminant level, Average 248
Public Notification Violation for National Primary Drinking Water Regulations 201
Monitoring and Reporting Disinfection Byproduct Rule 183
Failure to report information to the public or state agency in the Consumer Confidence Report 126
Failure to monitor, Routine Major (Coliform bacteria) 116
Maximum contaminant level, Monthly (Coliform bacteria) 102
Treatment Technique No Certif. Operator 62
Failure to monitor, Routine Minor (Coliform bacteria) 38
Failure to monitor, Repeat Major (Coliform bacteria) 34
Follow-up and Routine Tap Sampling 24
Other Non-National Primary Drinking Water Regulations Potential Health Risks 17
Inadequate reporting of information to the public 16
Failure to monitor, Repeat Minor (Coliform bacteria) 10
Initial Tap Sampling for Lead and Copper 7
Maximum contaminant level, Acute (Coliform bacteria) 6
Excess Turbidity at 0.3 NTU 5
Public Education 4
Over maximum contaminant level, Single Sample 3
Improper Treatment Techniques 2
Excess Turbidity at 1 NTU 1
Treatment Technique Precursor Removal 1
Filter Turbidity Reporting 1

Sources : EWG (Environmental Working Group)