State Well Water Guide
North Dakota Private Well Water Guide
North Dakota has one of the highest rates of private well use in the nation — about 48% of residents rely on private wells, reflecting the state's vast rural agricultural landscape. North Dakota's groundwater challenges are driven by its geology and land use: naturally occurring arsenic in glacial drift sediments, nitrate and bacterial contamination from livestock and crop agriculture, naturally high sulfate and total dissolved solids from sedimentary geology, and oil and gas contamination in the Bakken oil fields. The ND Department of Environmental Quality regulates well construction.
Testing Guidance
ND DEQ recommends annual testing for coliform bacteria and nitrates for all private wells. All well owners should test for arsenic given the state's documented natural arsenic problem. Western North Dakota Bakken oil country well owners should test for barium, strontium, chloride, and methane. High-sulfate water is common statewide — test TDS and sulfate as a baseline.
What to Test For in North Dakota
Total coliform bacteria and E. coli — annual minimum
Arsenic — documented natural occurrence throughout ND glacial sediments; test all wells
Nitrates — agricultural areas statewide
Sulfate and total dissolved solids — commonly elevated from sedimentary geology
Barium and strontium — Bakken oil region wells
Methane — near oil and gas operations
Iron and manganese — glacial drift wells throughout the state
Chloride — oil brine contamination indicator for Bakken area wells
Common Contamination Risks in North Dakota
Naturally occurring arsenic in glacial sediments — ND has among the highest rates of naturally elevated arsenic in private wells in the Upper Midwest; USGS and ND surveys have documented widespread arsenic above 10 ppb
Nitrate from agriculture — North Dakota's wheat, corn, and cattle production contributes nitrogen to shallow aquifers
Oil and gas contamination from Bakken operations — brine spills and pipeline leaks from the Williston Basin's oil boom have impacted groundwater in western ND
High sulfate and TDS from sedimentary geology — the glacial Lake Agassiz sediments and Upper Cretaceous geology naturally produce high-mineral groundwater
Bacterial contamination from livestock — cattle operations across the state
Contaminant Guides Relevant to ND Wells
PFAS
Synthetic Chemicals
EPA limit: 4 ppt
Lead
Heavy Metals
EPA limit: 15 ppb (action level)
Nitrates
Agricultural Chemicals
EPA limit: 10 mg/L
DBPs
Disinfection Byproducts
EPA limit: 80 µg/L (TTHMs) / 60 µg/L (HAA5)
Arsenic
Heavy Metals
EPA limit: 10 ppb
Hard Water
Minerals
EPA limit: No federal limit
Chlorine
Disinfection Chemicals
EPA limit: 4 mg/L (MRDL)
Microplastics
Emerging Contaminants
EPA limit: No federal limit
Bacteria
Microbial Contamination
EPA limit: Zero E. coli / < 1 coliform per 100 mL
Fluoride
Minerals
EPA limit: 4 mg/L (MCL) / 2 mg/L (Secondary MCL)
Chromium-6
Heavy Metals
EPA limit: 100 ppb (total chromium)
Copper
Heavy Metals
EPA limit: 1.3 mg/L (action level)
Radon
Radioactive Contaminants
EPA limit: No finalized MCL
Iron & Manganese
Minerals
EPA limit: 0.3 mg/L iron / 0.05 mg/L manganese (aesthetic SMCLs)
Atrazine
Agricultural Chemicals
EPA limit: 3 ppb (0.003 mg/L)
Uranium
Radioactive Contaminants
EPA limit: 30 µg/L (30 ppb)
Perchlorate
Industrial Chemicals
EPA limit: 0.056 mg/L (56 ppb)
VOCs
Industrial Chemicals
EPA limit: Varies by compound: benzene 5 ppb; TCE 5 ppb; PCE 5 ppb; vinyl chloride 2 ppb
Radium
Radioactive Contaminants
EPA limit: 5 pCi/L (combined Ra-226 + Ra-228)
Crypto & Giardia
Microbial Contamination
EPA limit: Zero (treatment technique standard)
Hydrogen Sulfide
Naturally Occurring Compounds
EPA limit: No MCL; Secondary MCL (aesthetic) of 0.05 mg/L
Selenium
Minerals
EPA limit: 50 ppb (0.05 mg/L)
Cadmium
Heavy Metals
EPA limit: 5 ppb (0.005 mg/L)
Mercury
Heavy Metals
EPA limit: 2 ppb (0.002 mg/L)
Barium
Heavy Metals
EPA limit: 2 mg/L
Find a Certified Lab in North Dakota
Use the North Dakota state-certified laboratory program to find accredited labs for private well testing. Always verify current certification before submitting samples.
ND Certified Lab Directory ↗North Dakota Well Water FAQs
Related Pages
Data Sources & Provenance
All data on this page is sourced from official U.S. government or public datasets.
Quick Reference
State program
ND Certified Labs ↗EPA guidance
EPA Private Wells Program ↗State lab directory
ND Certified Labs ↗Minimum Annual Tests
Plus state-specific contaminants listed above
Other State Guides