State Well Water Guide
Oklahoma Private Well Water Guide
About 25% of Oklahomans rely on private wells, concentrated in the rural eastern Oklahoma mountains and plains communities outside the reach of municipal water systems. Oklahoma's groundwater contamination concerns include nitrate from agricultural and poultry operations (particularly in the Panhandle and northeastern Oklahoma), naturally occurring radium and uranium in some western Oklahoma aquifers, arsenic from alluvial and geological sources, and oil and gas-related contamination (Oklahoma is a major petroleum state). ODEQ and the Oklahoma Water Resources Board regulate well construction and provide voluntary testing guidance.
Testing Guidance
ODEQ recommends annual testing for coliform bacteria and nitrates. Northeastern Oklahoma well owners near poultry operations should test for nitrates and bacteria. Western Oklahoma well owners using the Rush Springs aquifer or Blaine aquifer should test for radium and uranium. Oil country well owners in the Anadarko Basin and Arkoma Basin should test for barium, strontium, and methane. All well owners near current or former oil field operations should test for total petroleum hydrocarbons.
What to Test For in Oklahoma
Total coliform bacteria and E. coli — annual minimum
Nitrates — northeastern Oklahoma (Poultry Belt), Panhandle agricultural areas
Radium and uranium — western Oklahoma aquifers (Rush Springs, Blaine, Garber-Wellington)
Arsenic — some Oklahoma aquifer systems have naturally elevated arsenic
Barium, strontium, and methane — oil and gas producing areas
Iron and manganese — alluvial aquifer wells throughout the state
PFAS — near Tinker AFB, Vance AFB, Altus AFB, and other military installations
Total petroleum hydrocarbons — near oil field operations
Common Contamination Risks in Oklahoma
Nitrate from poultry operations — northeastern Oklahoma is the heart of the US poultry industry; the Illinois River watershed has been severely impacted by poultry litter runoff and groundwater nitrate loading
Oil and gas contamination — Oklahoma's extensive oil and gas production creates potential for brine spills, pipeline leaks, and wellbore integrity issues affecting groundwater
Naturally occurring radium and uranium in western aquifers — some Oklahoma aquifer systems have elevated naturally occurring radioactivity
PFAS from military installations — Oklahoma has numerous Air Force bases with AFFF histories
Arsenic from geological sources — some Oklahoma alluvial and bedrock aquifers have elevated natural arsenic
Contaminant Guides Relevant to OK 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 Oklahoma
Use the Oklahoma state-certified laboratory program to find accredited labs for private well testing. Always verify current certification before submitting samples.
OK Certified Lab Directory ↗Oklahoma 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
OK Certified Labs ↗EPA guidance
EPA Private Wells Program ↗State lab directory
OK Certified Labs ↗Minimum Annual Tests
Plus state-specific contaminants listed above
Other State Guides