Missouri Tap Water Quality Rankings 2026: 30th in Nation | WaterQ
Missouri ranks 30th out of the 50 states in our water quality assessment, earning an overall grade of B with an average score of 80. The state's 519 water systems serve a population of 5,525,182 residents. Despite the B grade, Missouri recorded 16,899 water quality violations across its systems, indicating areas where compliance challenges persist.
Key Findings for Missouri
Reviewing EPA SDWIS data for 2026, here's what defines Missouri's water quality landscape:
- As part of the Midwest agricultural plains, Missouri's water sources can be susceptible to agricultural runoff containing fertilizers, which often leads to elevated levels of nitrate.
- Communities with older housing stock or aging municipal infrastructure may face an increased risk of lead leaching into tap water from service lines or plumbing fixtures.
- Water systems situated near major river confluences, such as the Mississippi and Missouri rivers, can experience fluctuations in water quality due to upstream runoff and organic matter.
Most Common Contaminants in Missouri
Here's what Missouri residents should know about the contaminants most relevant to their water:
Nitrate
Elevated nitrate levels can occur in groundwater and surface water within agricultural regions due to fertilizer runoff and farming activity.
Lead
Lead typically enters drinking water through corrosion of plumbing materials, particularly in areas with older homes and legacy infrastructure.
Disinfection Byproducts
These compounds can form when chlorine used for disinfection reacts with naturally occurring organic matter in surface water sources.
Missouri's Best and Worst Cities for Water Quality
To see the specific water safety metrics and violation records for your local area, please consult the detailed city-by-city breakdown available on our Missouri water quality page. This allows residents to review data customized for their local water provider. Explore the full breakdown on our Missouri water systems page.
What Missouri Residents Should Do
Given Missouri's 30th place ranking, here's what matters most for residents:
- Search for your local water system's annual Consumer Confidence Report to review specific testing results.
- If you rely on a private well for drinking water, test it annually for common contaminants like nitrates and bacterial indicators.
- Consider installing a certified water filtration system tailored to target the specific contaminant categories identified in your area.
- Regularly check the EPA's database to stay informed about any recent violations in your local water system.
Frequently Asked Questions
How does Missouri water quality compare to other states?
Missouri ranks 30th out of the 50 US states in our assessment. It receives an overall water quality grade of B with an average score of 80. While this grade indicates moderate overall quality, the state still recorded 16,899 compliance violations across its 519 systems.
What are the most common contaminants in Missouri tap water?
Common contaminants of concern in Missouri often include nitrate from agricultural runoff in farming areas, as well as lead from older plumbing infrastructure. Disinfection byproducts may also be detected where surface water is treated with chlorine.
Is it safe to drink tap water in Missouri?
With a grade of B, Missouri's drinking water is generally considered safe for the majority of residents, but localized issues and violations do occur. Because 16,899 violations were recorded, it is advisable to check the violation history and specific reports for your local water provider.
Source: EPA SDWIS 2026 Compliance Data and WaterQ National Database. For more information on our ranking process, visit our state rankings page.