Jefferson Parish, Louisiana: drinking water report. Jefferson Parish borders New Orleans, serving about 440,000 residents.
Jefferson Parish borders New Orleans, serving about 440,000 residents. The Jefferson Parish Water Department draws from the Mississippi River, which by the time it reaches southeastern Louisiana has traveled over 2,300 miles and collected contributions from 31 states and 2 Canadian provinces. The river carries one of the most complex contaminant mixtures of any drinking water source in the country.
The Mississippi River at Jefferson Parish carries agricultural runoff (fertilizers, pesticides), industrial discharges, treated wastewater effluent, and sediment from the entire central United States. The parish's treatment plants handle this complex source water, but the variability of river chemistry – which changes with season, rainfall, and upstream activity – makes treatment a constant balancing act.
UCMR5 data shows PFAS detections in the Jefferson Parish system. According to the Louisiana Department of Health's 2024 monitoring data, PFAS concentrations were below proposed federal MCLs. However, the Mississippi River receives PFAS from the entire upstream watershed, making it one of the most diffuse contamination pathways in the country. Louisiana does not have state-specific PFAS standards.
The Mississippi River's complexity means the treatment burden on Jefferson Parish's system is inherently higher than most utilities face.
Check your water for current data in your area. A reverse osmosis system addresses the broadest range of contaminants. Our water filter guide covers which systems are certified for Mississippi River-specific concerns. Pull your detailed report, and visit our Louisiana page for statewide data.
Drinking water is one exposure route. These federal datasets also cover Jefferson Parish, LA.
The EPA places Jefferson Parish, LA in Zone 3 - the EPA's lowest-risk category, with a predicted average indoor radon level below 2 pCi/L. Zone maps predict an area's radon potential from geology and existing indoor readings; they say nothing about a specific house. Testing is the only way to know your own level.
64% of homes in Jefferson Parish, LA were built before 1980, and 7% before 1950. Residential lead paint was banned in 1978, so housing age is the strongest available proxy for lead-paint exposure. This describes the county's housing stock, not any one home.
Modelled annual fine-particle pollution (PM2.5) in Jefferson Parish, LA averages 8.7 µg/m³, within the EPA's annual standard of 9 µg/m³. These are CDC modelled county estimates rather than readings from a specific monitor.
How radon zones work · Air quality by county · Lead exposure guide