The Power of Information

National Drinking Water Database

South Dakota

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)398,179398,1797878
Alpha particle activity (excl radon and uranium)216,113216,1139797
Total trihalomethanes (TTHMs)33,06832,463109
Total haloacetic acids (HAAs)32,46332,46399
Mercury (total inorganic)3,79887671

Water Utilities in South Dakota Reporting Chemicals Exceeding Health Guidelines

Water utilities in South Dakota reporting chemicals exceeding health guidelines, according to an Environmental Working Group analysis of data obtained from state water authorities, include:

Chemicals tested
Chemicals found
Chemicals exceeding
health guidelines
Shirt Tail Gulch Development558274
Rapid City67,4308274
Saint Onge Sewer & Water Co2558264
Hot Springs5,0557454
Buffalo Gap1647354
Heartland Country Ranchettes928263
Cottonwood Grove Mobile Home Park298263
Rainbow Water Company1628253
Jamesville Colony1208263
Country Village/North2927443
Country Club Estates527443
Ponderosa Park407333
Blucksberg Mtn Water Association5284063
Rapid Valley Sanitary District7,7138273
Edelweiss Mountain Improvement Assoc638253
Colonial Pine Hills1,2608253

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.

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

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

11Sprawl 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

22Industrial 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)

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

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

12Naturally 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)

1Unregulated 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 Dakota85
 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 TypeNumber of Violations
Failure to monitor regularly1,715
Over maximum contaminant level, Average248
Public Notification Violation for National Primary Drinking Water Regulations201
Monitoring and Reporting Disinfection Byproduct Rule183
Failure to report information to the public or state agency in the Consumer Confidence Report126
Failure to monitor, Routine Major (Coliform bacteria)116
Maximum contaminant level, Monthly (Coliform bacteria)102
Treatment Technique No Certif. Operator62
Failure to monitor, Routine Minor (Coliform bacteria)38
Failure to monitor, Repeat Major (Coliform bacteria)34
Follow-up and Routine Tap Sampling24
Other Non-National Primary Drinking Water Regulations Potential Health Risks17
Inadequate reporting of information to the public16
Failure to monitor, Repeat Minor (Coliform bacteria)10
Initial Tap Sampling for Lead and Copper7
Maximum contaminant level, Acute (Coliform bacteria)6
Excess Turbidity at 0.3 NTU5
Public Education4
Over maximum contaminant level, Single Sample3
Improper Treatment Techniques2
Excess Turbidity at 1 NTU1
Treatment Technique Precursor Removal1
Filter Turbidity Reporting1