Memphis – Tennessee – Water Quality Report 2025: PFAS Testing, Infrastructure Concerns & Safety across your city
Memphis Light, Gas and Water (MLGW) manages one of the most unique water systems in the United States, serving approximately 257,000 water customers in Memphis and Shelby County. MLGW operates one of the largest artesian well systems in the world, with 10 water pumping stations and more than 175 wells that draw water from the Memphis Sand Aquifer.
While most cities in the world obtain their drinking water from surface sources such as rivers and lakes, Memphis enjoys the rare privilege of drawing its water from deep underground. The Memphis Sand Aquifer (also known as the Memphis Aquifer or Sparta Aquifer outside of Tennessee) contains more than 100 trillion gallons of naturally filtered rainwater that scientists believe fell to earth as long as 2,000 years ago. This pristine water resource undergoes minimal treatment due to its exceptional purity, which comes from a natural filtration system of alternating layers of clay, sand, and gravel that sift out impurities. Memphis is the largest city in the United States that relies 100% on groundwater to meet all of its water needs.
Memphis Water Quality: Current Status (2024-2025)
Latest Testing Results
- Exceptional Water Quality: Memphis’s water consistently meets or exceeds all federal and state drinking water standards. MLGW’s Water Quality Assurance Laboratory conducts more than 100 tests daily to ensure water quality and safety, with over 40,000 tests performed annually.
- Lead and Copper Levels: According to recent testing, Memphis water has had no detectable lead in its source water. Some older homes (built before the 1940s) may have lead service lines, and homes built before 1987 may have lead solder in their plumbing, but the water itself is lead-free when it leaves the treatment facilities.
- Compliance Status: MLGW maintains the highest available rating from the Tennessee Department of Environment and Conservation (TDEC), receiving a 98% score in their most recent biennial sanitary survey of the water system.
Memphis Sand Aquifer Characteristics
- Ancient Water Source: The Memphis Sand Aquifer contains water that is estimated to be over 2,000 years old, having slowly filtered through multiple layers of sand and clay over millennia.
- Natural Protection: The aquifer is generally protected by a clay confining layer that acts as a barrier to potential contaminants from the shallow aquifer above. However, research has identified areas where this protective clay layer is thin or absent, creating “breaches” that require monitoring.
- Recharge Zones: The aquifer is primarily recharged in areas outside of Shelby County where the protective clay layer is naturally absent, allowing rainfall to replenish the groundwater supply.
Minimal Treatment Process
- Aeration: Due to the exceptional purity of the Memphis aquifer water, treatment is minimal compared to surface water systems. The primary treatment involves aeration to remove naturally occurring iron.
- Disinfection: The water is disinfected with sodium hypochlorite (a form of chlorine) to ensure it remains free of harmful bacteria as it travels through the distribution system.
- Additives: Small amounts of fluoride are added for dental health, and phosphate is added to prevent pipe corrosion in the distribution system.
Aquifer Protection Efforts
- Breach Monitoring: The Center for Applied Earth Science and Engineering Research (CAESER) at the University of Memphis conducts ongoing studies to map and monitor potential breaches in the protective clay layer above the Memphis Sand Aquifer.
- Local Ordinances: In 2021, the Shelby County Commission and Memphis City Council passed ordinances to enhance protection of the Memphis Sand Aquifer from potential contamination sources, particularly in areas with known breaches or near wellfields.
- Cross Connection Control: MLGW maintains a Cross Connection Control Program that requires appropriate backflow prevention devices to protect the water supply from contamination that could occur through cross connections in the plumbing system.
Future Challenges and Protections
While Memphis’s water is renowned for its quality, the city faces challenges in protecting this precious resource. Growing concerns include the potential for contamination through identified breaches in the protective clay layer, industrial development near wellfields, and the need for more comprehensive aquifer management across county and state lines, as the aquifer extends into multiple states. Community advocacy groups like Protect Our Aquifer work alongside MLGW, CAESER, and government agencies to promote sustainable water use, advance protective policies, and increase public awareness about Memphis’s unique water resource. Ongoing research and monitoring are essential to ensure that Memphis’s exceptional water quality is maintained for future generations.
Recommendations for Memphis Residents
Check for Lead Pipes
If your home was built before 1940, it may have lead service lines. Homes built between 1940 and 1987 may have lead solder in the plumbing. Contact MLGW at 901-544-6549 to discuss lead testing options for your water.
Flush Your Pipes
If water has been sitting in pipes for several hours, run cold water for 2-3 minutes until noticeably cooler before using for drinking or cooking. This is especially important for homes with older plumbing that may contain lead components.
Use Cold Water for Consumption
Always use cold water for drinking, cooking, and especially for making baby formula. Hot water can dissolve more metals from your plumbing. If you need hot water for food or drinks, heat cold water on the stove or in the microwave.
Prevent Cross Connections
Make sure your home plumbing doesn’t create “cross connections” that could allow contaminants to enter your drinking water. Never leave garden hoses submerged in pools, buckets, or sinks. Install backflow prevention devices on irrigation systems and other potential cross-connection points.
Support Aquifer Protection
Help protect Memphis’s precious water resource by supporting local aquifer protection initiatives. Properly dispose of household chemicals, pharmaceuticals, and other potential contaminants. Never dump anything down storm drains, as some areas have direct connections to the groundwater system.
Frequently Asked Questions
Why is Memphis water considered so special?
Memphis water is considered exceptional because it comes from the Memphis Sand Aquifer, a vast underground reservoir containing water that has been naturally filtered through layers of sand and clay for thousands of years.
Unlike most major cities that obtain their water from surface sources like rivers and lakes, Memphis draws its drinking water from deep underground where it has been protected from modern pollution. This ancient water requires minimal treatment – mainly just aeration, disinfection, and the addition of fluoride and corrosion inhibitors. The exceptional purity of Memphis water gives it a clean, refreshing taste that is often recognized in national water quality competitions. Memphis is the largest city in the United States that relies 100% on groundwater to meet all of its water needs.
What are the main threats to Memphis’s water supply?
While Memphis’s water is naturally protected by a layer of clay above the Memphis Sand Aquifer, there are several concerns about potential threats to this valuable resource:
• Breaches in the protective clay layer: Researchers have identified areas where the protective clay layer is thin or missing, creating pathways for shallow groundwater contaminants to potentially reach the Memphis Aquifer
• Industrial development: Concerns exist about industrial facilities, landfills, and other potential pollution sources located near wellfields or in areas with known breaches
• Pipeline and infrastructure projects: Proposed pipelines and other infrastructure that could pose contamination risks have prompted community action to protect the aquifer
• Cross-jurisdictional management: The Memphis Sand Aquifer extends across multiple counties and states, making comprehensive management challenging
Organizations like the Center for Applied Earth Science and Engineering Research (CAESER) at the University of Memphis and advocacy groups like Protect Our Aquifer work to study these threats and promote policies to protect Memphis’s water supply for future generations.
How is Memphis water treated?
Memphis water undergoes minimal treatment compared to surface water systems, thanks to the natural purity of the Memphis Sand Aquifer. The treatment process includes:
• Extraction: Water is pumped from the Memphis Sand Aquifer through wells that range from 350 to 1,100 feet deep
• Aeration: The water passes through aerators to remove naturally occurring iron and other dissolved gases
• Disinfection: Sodium hypochlorite (a chlorine-based disinfectant) is added to kill any potential pathogens
• Fluoridation: A small amount of fluoride is added for dental health benefits
• Corrosion control: Phosphate is added to prevent corrosion in distribution pipes and reduce the potential for lead or copper to leach from older plumbing
MLGW’s Water Quality Assurance Laboratory conducts more than 100 tests daily to monitor water quality, ensuring that it consistently meets or exceeds all federal and state standards. The simplicity of this treatment process is a testament to the exceptional quality of Memphis’s groundwater source.
Should I be concerned about lead in Memphis water?
Memphis’s source water from the Memphis Sand Aquifer has no detectable lead. However, lead can enter drinking water through contact with lead service lines, lead solder, or plumbing fixtures containing lead, particularly in older homes.
Homes built before the 1940s may have lead service lines, and homes built before 1987 may have lead solder in their plumbing. MLGW’s corrosion control measures help prevent lead from leaching into the water, but residents of older homes may want to take additional precautions:
• Run cold water for 2-3 minutes after it has been sitting in pipes for several hours
• Always use cold water for drinking, cooking, and making baby formula
• Consider having your water tested if you live in an older home
• If concerned, use a water filter certified for lead reduction (look for NSF/ANSI Standard 53)
If you’re unsure about the materials in your home’s plumbing system, contact MLGW at 901-544-6549 for guidance on lead testing options. They can provide information on how to identify lead pipes and what steps to take if lead is detected in your water.
Contaminants of Concern
Lead
Source: Not present in source water; may enter water through contact with lead service lines (in homes built before the 1940s), lead solder (in homes built before 1987), or brass fixtures containing lead
Health Effects: Developmental delays in children, reduced IQ, learning difficulties, kidney problems, cardiovascular effects in adults
Current Status: Memphis water has no detectable lead in its source water. MLGW uses phosphate as a corrosion inhibitor to prevent lead from leaching from plumbing materials. EPA Limit: Action level 15 ppb, but no level of lead is considered safe
Disinfection Byproducts
Source: Form when chlorine-based disinfectants react with naturally occurring organic matter in the water
Health Effects: Potential increased risk of bladder cancer and reproductive issues with long-term exposure to elevated levels
Current Status: Due to the exceptional purity of Memphis’s source water and minimal treatment required, disinfection byproduct levels are typically lower than in cities using surface water sources. Memphis water consistently meets all EPA standards for trihalomethanes (THMs) and haloacetic acids (HAAs).
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