The safety of a city’s drinking water supply is determined by its compliance with federal regulations set by the Environmental Protection Agency (EPA), specifically the standards outlined in the Safe Drinking Water Act. Because many large urban areas face significant infrastructure and environmental challenges, residents often question the quality of their local tap water. Understanding the source, treatment, and distribution system addresses these public health concerns.
The Immediate Safety Status
New Orleans tap water is generally considered safe to drink because the Sewerage and Water Board of New Orleans (SWBNO) meets federal regulatory standards. The utility treats the water to EPA specifications and regularly monitors the supply for contaminants, ensuring the water leaving the treatment plants meets health-based limits. However, this determination represents a system-wide average and does not account for localized issues within the distribution network or individual homes. The system’s compliance is publicly documented in annual water quality reports.
Despite this compliance, safety can be temporarily compromised by infrastructure failures or environmental events. Such incidents often lead to precautionary boil water advisories, alerting residents that the water may be unsafe due to a drop in pressure or a main break.
The Water Source and Treatment Process
New Orleans draws its municipal water supply directly from the Mississippi River, a dynamic surface source that presents unique purification challenges. Flowing through the country’s heartland, the river carries a high load of suspended solids, organic material, and runoff contaminants. The SWBNO operates the Carrollton and Algiers Water Purification Plants to transform this raw river water into potable drinking water.
The purification process begins with coagulation, where chemicals are added to cause fine particles to clump together. This is followed by flocculation, a gentle mixing process that allows these clumps (floc) to grow larger and denser.
Next is sedimentation, where gravity pulls the heavy floc to the bottom of settling basins, separating the solid material from the water. The water then undergoes disinfection by adding chlorine and ammonia, creating chloramine, which maintains a residual disinfectant throughout the network. The final stage is filtration through fine sand and carbon to remove remaining microscopic particles.
Specific Contaminants and Local Infrastructure Concerns
Lead Service Lines
The greatest threat to New Orleans water quality often comes from the aging infrastructure that delivers the water to individual taps. The city has lead service lines (LSLs), which connect the water main to customer properties. While the water leaving the treatment plants is lead-free, lead can leach into the drinking water when it sits stagnant in these old pipes or when the pipes are disturbed. The SWBNO has identified approximately 15,000 service lines needing replacement. The utility actively employs corrosion control by adding lime to the water, which helps prevent lead from dissolving into the supply.
Chemical Byproducts and Emerging Contaminants
The Mississippi River source introduces chemical challenges. Disinfection byproducts, such as Total Trihalomethanes (TTHMs), form when chlorine reacts with natural organic matter. Although TTHM levels remain within the EPA’s legal limits, they have been observed to be higher than some health-based guidelines recommended by non-regulatory groups.
Agricultural runoff contributes to nitrates in the water supply. Nitrates are a concern for infants and pregnant women, and testing has shown levels ten times higher than some public health guidelines, though still below the EPA maximum. Emerging contaminants like Per- and Polyfluoroalkyl Substances (PFAS), or “forever chemicals,” have also been detected in the treated water below the EPA’s proposed limits.
Environmental Vulnerabilities
The city is vulnerable to environmental extremes, such as saltwater intrusion from the Gulf of Mexico during periods of low river flow. This occurs when the river’s volume is too low to hold back the denser salt wedge from advancing upstream toward the water intakes. Infrastructure issues, like water main breaks or power failures, can also cause pressure drops, necessitating precautionary boil water advisories to prevent microbial contamination.
Consumer Steps for Added Security
For residents seeking to minimize potential risks, the most important step is to read the annual Consumer Confidence Report (CCR) provided by the utility. This report details all detected contaminants and confirms the system’s compliance with regulatory standards. Residents can also check if their home is among the properties identified as having a lead service line using the SWBNO’s online inventory map.
To reduce lead exposure, always use cold water for drinking, cooking, and preparing baby formula. If water has been standing in the pipes, flush the cold water tap for at least five minutes before use. The SWBNO offers free lead testing kits for residential locations in Orleans Parish.
Installing a certified home water filter is an effective measure for added security. Filters certified to NSF/ANSI standards can reduce specific contaminants like lead and TTHMs. Activated carbon filters are effective for removing disinfection byproducts, while reverse osmosis systems can target a broader range of contaminants, including nitrates and PFAS.