Statewide Compliance and Testing

• Overall Compliance: The majority of Missouri’s public water systems meet federal Safe Drinking Water Act standards. Missouri American Water, serving 1.6 million residents across more than 90 counties, consistently meets or surpasses all state and federal regulations including those for lead, and has filed a $1.5 billion investment plan covering 2023 through May 2026.
• PFAS Monitoring Complete: Missouri completed voluntary PFAS sampling of every community water system in the state by end of 2025, finishing two years ahead of federal requirements. Monitoring has covered public water supplies serving more than 76% of Missouri’s population (approximately 4.7 million people), with MoDNR’s interactive PFAS Viewer Tool providing publicly accessible results. Visit our water quality database to compare national PFAS data.
• Infrastructure Investment: Missouri American Water’s $1.5 billion programme (2023–2026) includes replacement of over 250 miles of aging water and wastewater pipe. Additional federal Bipartisan Infrastructure Law funds continue to flow through the Clean Water and Drinking Water State Revolving Funds for treatment upgrades, emerging contaminant removal, and disadvantaged community support.

Major Water Sources and Challenges

• Missouri River System: Primary water source for much of northern and central Missouri, including Kansas City and Columbia areas, requiring ongoing monitoring for agricultural runoff and PFAS detection. See our Kansas City water quality report for detailed local data.
• Mississippi River Basin: Serves St. Louis metropolitan area and eastern Missouri communities, with documented challenges from urban runoff and legacy industrial contamination. Advanced treatment is required for chromium-6 levels averaging 1,600 parts per trillion in St. Louis. See our St. Louis water quality report for full analysis.
• Aging Infrastructure Concerns: Kansas City experienced a record 1,844 water main breaks in 2012, while St. Louis deals with water mains averaging 55 to 65 years of age, requiring an estimated $8.5 billion in infrastructure investments over 20 years according to EPA assessments. Missouri American Water’s ongoing pipe replacement programme directly addresses these legacy issues.

PFAS Regulatory Update for 2026

• Revised EPA Standards: The EPA announced in May 2025 that MCLs for four of the six originally regulated PFAS (PFHxS, PFNA, GenX chemicals, and PFBS) would be rescinded. PFOA and PFOS MCLs of 4 parts per trillion each remain in force. The compliance deadline for water systems has been extended from 2029 to 2031. Missouri continues its own testing programme regardless. Track regulatory developments via our Water Alert News page.
• Statewide Sampling Completed: Missouri completed sampling of all community water systems by end of 2025, giving the state one of the most comprehensive PFAS monitoring datasets in the region. MoDNR continues publishing results via its interactive PFAS Viewer Tool.
• Phase 2 PFAS Settlement: Missouri public water systems are eligible for Phase 2 PFAS settlement funds from 3M and DuPont, with action fund payments expected from late 2026 onward. These funds can be used for PFAS testing, remediation planning, and treatment technology implementation.
• Treatment Technology Deployment: Utilities are implementing activated carbon filtration and reverse osmosis systems, with systems like Springfield already blending PFAS-affected James River sources with cleaner water to reduce contaminant levels. If you are concerned about PFAS in your area, see our recommended PFAS water filters.

Rural and Disadvantaged Communities

• Infrastructure Disparities: Rural water systems face disproportionate challenges with aging infrastructure, limited technical capacity, and higher per-capita costs for compliance with evolving contaminant regulations, particularly PFAS treatment requirements.
• Targeted Federal Support: Communities with fewer than 10,000 people and disadvantaged conditions remain eligible for federal grants to purchase sampling equipment and monitor water for emerging contaminants, though ongoing operational costs for treatment systems remain a challenge.
• Technical Assistance Programmes: MoDNR and EPA provide enhanced technical support to help smaller systems navigate complex regulatory requirements and secure funding for necessary improvements through state revolving fund programmes and competitive grant opportunities.

Looking Forward: 2026–2031

Missouri’s water quality landscape continues to evolve in 2026. The state’s proactive approach — completing statewide PFAS sampling ahead of schedule and maintaining robust monitoring through MoDNR’s PFAS Viewer Tool — positions Missouri well despite the federal regulatory uncertainty following the EPA’s partial rescission of PFAS MCLs. Missouri American Water’s $1.5 billion infrastructure investment programme and incoming Phase 2 PFAS settlement funds provide additional resources for treatment upgrades. The remaining challenges are significant: the estimated $8.5 billion 20-year infrastructure need, chromium-6 contamination in St. Louis at 63 times health guidelines, and disinfection byproduct levels in major cities all require continued investment and vigilance. All Missourians — particularly those in St. Louis, Springfield, and communities near military installations — are encouraged to review their utility’s water quality data, check our live boil water notice tracker, and consider certified filtration as a precautionary measure.