Oklahoma Tap Water Quality Rankings 2026: 49th in Nation | WaterQ
Oklahoma ranks 49th out of 50 states for drinking water quality, receiving an average score of 41 and a grade of F. Across the state, 405 water systems serve a population of 3,490,619 residents. The state has registered 18,881 violations, highlighting significant infrastructure and compliance issues.
Key Findings for Oklahoma
Reviewing EPA SDWIS data for 2026, here's what defines Oklahoma's water quality landscape:
- Runoff from agricultural activities in the south-central plains can introduce contaminants like nitrates and pesticides into local water supplies.
- The regional legacy of the oil and gas industry introduces risks of industrial byproduct contamination in some groundwater sources.
- With 18,881 violations across 405 water systems, public water infrastructure in the state faces widespread compliance and monitoring challenges.
Most Common Contaminants in Oklahoma
Here's what Oklahoma residents should know about the contaminants most relevant to their water:
Nitrate
Typically originates from fertilizer runoff and animal waste in agricultural areas, posing risks to rural groundwater supplies.
Disinfection Byproducts
These compounds can form during the treatment process when chemical disinfectants react with organic matter in source waters.
Industrial Chemicals
Potential runoff and infiltration risks associated with the region's history of oil and gas extraction and industrial production.
Oklahoma's Best and Worst Cities for Water Quality
To view the specific compliance records and water quality testing results for individual communities, please consult the city-by-city directory on our state portal. Explore the full breakdown on our Oklahoma water systems page.
What Oklahoma Residents Should Do
Given Oklahoma's 49th place ranking, here's what matters most for residents:
- Search the database for your specific municipal water system to review its local violation history.
- Test private wells annually for common contaminants, as private systems are not regulated under the Safe Drinking Water Act.
- Consider installing a water filtration system certified to target the specific contaminants identified in your local water system.
- Regularly review the annual Consumer Confidence Report provided by your local water utility.
Frequently Asked Questions
How does Oklahoma water quality compare to other states?
Oklahoma ranks 49th out of 50 states in our drinking water quality assessment. The state has been assigned a grade of F with an average score of 41 due to widespread violation and compliance challenges. This low score reflects significant issues across its 405 water systems.
What are the most common contaminants in Oklahoma tap water?
The most common contaminants typically associated with Oklahoma's water supply include agricultural nitrates and disinfection byproducts. Additionally, the region's legacy of oil and gas industrial activities presents risks of groundwater contamination. These contaminants can enter the water supply through runoff, chemical reactions during treatment, or industrial operations.
Is it safe to drink tap water in Oklahoma?
With a grade of F and 18,881 violations across 405 water systems, the safety of tap water in Oklahoma varies significantly and presents clear compliance challenges. Residents are advised to look up their local system's specific testing records rather than assuming safety. Using certified water filtration systems can also provide an additional layer of safety for households.
Source: EPA SDWIS 2026 Compliance Data and WaterQ National Database. For more information on our ranking process, visit our state rankings page.