South Dakota has cleaner overall water quality, benefiting from lower industrial activity and fewer contamination sources. North Dakota faces oil industry risks from the Bakken formation and PFAS contamination from military bases including Minot and Grand Forks Air Force Bases. Both states have low population density and good source water, but North Dakota's extraction economy creates more water quality risk.
The two Dakotas share the Great Plains landscape and agricultural economies, but their water quality diverges where their industries diverge. North Dakota's Bakken oil boom brought prosperity and contamination risk. South Dakota's economy relies more on agriculture and tourism, producing less industrial water pollution. Both states face basic infrastructure challenges – serving small, scattered communities across vast distances with limited budgets.
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South Dakota's Department of Agriculture and Natural Resources manages about 600 public water systems serving 700,000 residents. North Dakota's Department of Environmental Quality oversees roughly 500 systems for 780,000 people. Both states have high rates of private well use, particularly on farms and ranches.
Check your water quality by zip code for your system's results.
North Dakota's PFAS sources include Minot Air Force Base and Grand Forks Air Force Base, both of which have confirmed PFAS in groundwater from AFFF firefighting foam use. According to DoD data from 2024, Minot AFB's PFAS plume has affected nearby private wells and prompted the Air Force to provide alternative water supplies to some residents.
South Dakota has fewer military PFAS sites – Ellsworth Air Force Base near Rapid City is the primary one. The state's lower PFAS detection rate of about 20% reflects both fewer sources and less industrialization. Sioux Falls and Rapid City water systems generally show low or no PFAS detections.
Both states draw from the Missouri River system and underlying aquifers. Sioux Falls draws from wells along the Big Sioux aquifer. Fargo, ND draws from the Red River and Sheyenne River. The water sources are generally clean – low industrial density upstream means less contamination than Midwest states along major industrial rivers.
North Dakota's Bakken oil region in the western part of the state generates produced water that must be properly managed. According to the North Dakota Industrial Commission, oil wells in the Bakken produce roughly 1.5 barrels of water for every barrel of oil. Spills and improper disposal have contaminated surface water and groundwater in localized areas. A 2015 pipeline spill near Williston leaked 3 million gallons of saltwater brine into the Blacktail Creek.
Tribal water systems on reservations in both states face severe infrastructure challenges. The Standing Rock, Pine Ridge, and Rosebud reservations have documented water system deficiencies that predate and exceed the national average for underinvestment.
Neither state has set PFAS standards beyond federal limits. Both follow the federal Safe Drinking Water Act framework. North Dakota has oil and gas regulations through the Industrial Commission, but environmental groups have criticized the state for prioritizing production over environmental protection. South Dakota's regulatory load is lighter because there's less to regulate.
South Dakota has cleaner water overall – fewer contamination sources, lower PFAS detection rates, and less industrial activity threatening water quality. North Dakota's oil economy creates risks that South Dakota doesn't face, and its military base PFAS contamination is more extensive.
Both states benefit from low population density and clean Great Plains source water. For most residents of either state, water quality is above the national average. The risks are localized – near oil fields in western ND, near military bases, and on underserved tribal reservations.
Check your water quality by zip code for your system's EPA data. North Dakota oil country residents should test for total dissolved solids and radionuclides in addition to PFAS.
If contamination is found, the AquaTru reverse osmosis system handles PFAS, nitrates, and dissolved solids. The Brita Elite handles lead and chlorine basics. See our water filter guide.
Detailed analysis: get a water quality PDF report. State pages: South Dakota and North Dakota.
Is South Dakota or North Dakota water safer? South Dakota has cleaner water overall with fewer contamination sources. North Dakota faces oil industry contamination risks in the Bakken region and more military PFAS sites. Both states have good source water and low population density.
Does North Dakota oil drilling affect drinking water? Oil operations in the Bakken produce large volumes of salty produced water. Spills and improper disposal have contaminated localized areas. A 2015 spill near Williston leaked 3 million gallons of brine. The risk is concentrated in western North Dakota's oil-producing counties.
Is Sioux Falls water safe? Sioux Falls draws from the Big Sioux aquifer and meets all federal drinking water standards. PFAS detection rates are low. The system is well-managed and serves as one of the cleanest urban water supplies in the Great Plains.
Does Minot Air Force Base contaminate water? Yes. Minot AFB has confirmed PFAS in groundwater from firefighting foam use. The contamination plume has affected nearby private wells, and the Air Force has provided alternative water supplies to some affected residents. Monitoring and remediation are ongoing.
Do the Dakotas have PFAS limits? Neither South Dakota nor North Dakota has set state-level PFAS limits beyond the federal EPA standard of 4 ppt for PFOA and PFOS. Both states rely entirely on federal regulation for PFAS in drinking water.