St. Louis – Missouri – Water Quality Report 2025: PFAS Testing, Infrastructure Concerns & Safety across your city
St. Louis Water Division, established in 1835, manages one of the oldest municipal water systems in the American Midwest, serving approximately 1.1 million residents across St. Louis City and parts of St. Louis County. The system includes over 1,300 miles of water mains, two treatment plants, and numerous pumping stations, delivering an average of 135 million gallons daily throughout the metropolitan area.
St. Louis draws its drinking water exclusively from the Mississippi River, one of America’s most significant waterways. The city utilizes two intake points along the river, with primary treatment occurring at the Chain of Rocks Plant and Howard Bend Treatment Plant. Despite sourcing from a river with varied water quality challenges, St. Louis has developed sophisticated treatment processes that consistently produce high-quality drinking water. The city has received multiple awards for water quality excellence, though like many older urban centers, it continues addressing aging infrastructure and emerging contaminant concerns through proactive management strategies and significant capital improvement programs.
St. Louis Water Quality: Current Status (2024-2025)
Latest Testing Results
- Lead Levels: The most recent testing period (January-December 2023) showed 90th percentile lead levels of 10.5 parts per billion (ppb), below the EPA action level of 15 ppb but indicating the continued presence of lead service lines in older neighborhoods throughout the city.
- Testing Scope: St. Louis conducts over 70,000 water quality tests annually across its distribution system, with enhanced monitoring for lead, disinfection byproducts, and emerging contaminants throughout the service area.
- Compliance Status: St. Louis water meets or exceeds all federal and state drinking water standards, maintaining full compliance with EPA and Missouri Department of Natural Resources regulations.
Mississippi River Source
- River Monitoring: Continuous real-time monitoring at intake points tracks water quality parameters including turbidity, temperature, pH, and potential contaminants.
- Watershed Management: Participation in the Upper Mississippi River Basin Association promotes collaborative watershed protection and monitoring programs across multiple states.
- Source Water Protection: Comprehensive source water assessment program identifies and addresses potential contamination sources upstream of city intakes.
Advanced Treatment Technology
- Multi-Stage Processing: Treatment includes pre-sedimentation, coagulation, flocculation, sedimentation, granular activated carbon filtration, and disinfection to address varied river water conditions.
- Enhanced Clarification: Utilizes advanced clarification technologies including plate settlers and high-rate clarification systems to address seasonal turbidity variations.
- Corrosion Control: Optimized orthophosphate treatment prevents lead and copper leaching, with lime addition for pH stabilization and alkalinity management throughout the distribution system.
Infrastructure Modernization
- Pipeline Replacement: Annual replacement of approximately 15 miles of aging water mains, prioritizing areas with high break frequency and oldest infrastructure components.
- Lead Service Line Program: Comprehensive inventory and replacement initiative addressing the estimated 80,000 lead service lines throughout the system, with priority for schools, daycares, and vulnerable populations.
- System Monitoring: Advanced SCADA systems and pressure monitoring network provide real-time data on system operations, enabling rapid response to potential water quality issues.
Customer Protection Initiatives
St. Louis offers comprehensive customer support including complimentary water quality testing, filter distribution for vulnerable households, and payment assistance programs for eligible residents. The city’s Lead Elimination Assistance Program (LEAP) provides financial assistance for lead service line replacement, while educational outreach campaigns help residents understand water quality management and conservation practices. St. Louis demonstrates commitment to environmental justice by prioritizing infrastructure improvements in historically underserved neighborhoods while maintaining transparent communication about water quality and system maintenance activities. The city’s long tradition of Mississippi River water purification, combined with continual investment in treatment technology, ensures reliable, high-quality water delivery throughout the metropolitan area.
Recommendations for St. Louis Residents
Request Free Testing
Contact the Water Quality Laboratory at (314) 531-7273 or visit stlwater.com to request complimentary water testing. Testing is particularly important for homes built before 1986 or in neighborhoods with known lead service lines.
Apply for LEAP Program
Enroll in the Lead Elimination Assistance Program (LEAP) for financial assistance with lead service line replacement. Call (314) 664-6609 or visit stlwater.com/leap to begin the application process and determine eligibility for subsidized replacement.
Install Certified Filters
For homes with lead service lines or elevated lead levels, use NSF-certified filters (Standard 53) for drinking and cooking water. Low-income households may qualify for free filter systems through the city’s Safe Water Program.
Flush Your Pipes
If water has been stagnant for 6+ hours, run cold water for 2-3 minutes before using for consumption. Always use cold water for drinking and cooking, as hot water can contain higher levels of metals from household plumbing.
Report Water Issues
Contact Customer Service at (314) 622-4545 for water main breaks, pressure problems, or quality concerns. For after-hours emergencies, call the 24-hour emergency line at (314) 771-4880. Report issues promptly to ensure rapid response.
Frequently Asked Questions
Is St. Louis tap water safe to drink?
Yes, St. Louis tap water consistently meets all federal and state drinking water standards. The city employs advanced multi-barrier treatment processes to address Mississippi River source water challenges, including enhanced clarification, filtration, and disinfection technologies.
However, lead may enter water through service lines and older plumbing fixtures in homes built before 1986. Recent testing shows 90th percentile lead levels at 10.5 ppb, below the EPA action level but still a concern. The city provides free water testing, filter programs, and lead service line replacement assistance. Residents in older homes should consider having their water tested and using certified filters as a precautionary measure.
How do I know if my home has lead pipes?
St. Louis maintains records of service line materials, although many older installations are undocumented. To determine if your home has lead pipes:
1. Inspect the service line where water enters your home (typically in the basement). Lead pipes have a dull gray color, are soft enough to scratch with a coin, and won’t attract a magnet.
2. Contact the Water Division at (314) 771-2255 to request service line material verification.
3. Review property records if your home was built before 1950.
The Lead Elimination Assistance Program (LEAP) offers financial assistance for lead service line replacement. Homes built before 1950 are most likely to have lead service lines, though some were installed through the 1980s in certain neighborhoods.
Why does St. Louis water sometimes taste different?
Seasonal variations in taste and odor can occur due to several factors:
• River conditions: Mississippi River water quality changes seasonally with temperature, rainfall, and upstream activities
• Algae blooms: Spring and summer algae growth can introduce compounds that affect taste, though treatment processes remove these effectively
• Treatment adjustments: Chemical dosages may be modified to address changing river conditions
• Distribution system: Water age in certain areas of the distribution network can affect taste, particularly during low-demand periods
These taste variations do not indicate safety concerns. The Water Division constantly monitors and adjusts treatment processes to minimize seasonal taste and odor changes while maintaining disinfection effectiveness. Refrigerating tap water or using activated carbon filters can improve taste if needed.
Does St. Louis have water restrictions?
St. Louis rarely implements mandatory water restrictions due to its abundant Mississippi River source and significant treatment capacity. However, the city maintains conservation guidelines:
Everyday Conservation Recommendations:
• Water lawns during early morning or evening hours
• Use brooms instead of hoses for cleaning outdoor surfaces
• Install water-efficient fixtures and appliances
• Repair leaking fixtures promptly
Emergency Response:
During infrastructure emergencies or treatment plant maintenance, temporary restrictions may be implemented:
• Odd-even day lawn watering schedules
• Restrictions on non-essential water uses
• Temporary conservation measures
Current status information is available through the Water Division website or customer service line (314) 622-4545.
Contaminants of Concern
Lead
Source: Lead service lines and older plumbing fixtures in homes built before 1986; St. Louis has approximately 80,000 lead service lines throughout the city
Health Effects: Developmental delays in children, reduced IQ, learning difficulties, kidney problems, cardiovascular effects in adults
Current Levels: 90th percentile value of 10.5 ppb, below EPA action level of 15 ppb EPA Limit: Action level 15 ppb, but no level of lead is considered safe
Disinfection Byproducts
Source: Form when chlorine disinfectants react with naturally occurring organic materials in Mississippi River water
Health Effects: Potential increased risk of bladder cancer and reproductive effects with long-term exposure to elevated levels
Current Status: Maintained significantly below EPA limits through treatment optimization and granular activated carbon filtration; monitored at multiple points throughout the distribution system
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