Metairie Water Hardness & Quality Report (2026)

Metairie, Louisiana — the largest suburb of New Orleans, located in Jefferson Parish — receives its municipal water supply from the Jefferson Parish Water System, drawing directly from the Mississippi River at water treatment facilities on the east bank of Jefferson Parish. The lower Mississippi River at the New Orleans metropolitan area represents the terminus of drainage from 1.15 million square miles of the central North American continent. Raw Mississippi River water undergoes conventional treatment — including coagulation, sedimentation, filtration, and disinfection — at the Jefferson Parish Water Treatment Plant before distribution throughout the unincorporated Jefferson Parish communities, including Metairie. Water hardness measures 112 mg/L — classified as moderately hard.

Metairie's moderate hardness reflects the blended, continental mineral character of the lower Mississippi River at this reach. The Mississippi collects dissolved calcium and bicarbonate from Carboniferous and Paleozoic limestone and dolomite of the Appalachian Mountains and Midwest carbonate platform; Cretaceous chalk and marl from the Southern Plains; Devonian carbonate formations from the Great Lakes and Ohio Valley regions; and Tertiary calcareous coastal plain formations from the Gulf states. Despite this calcium-rich catchment, the immense discharge volume of the Mississippi — the fourth-largest river in the world by discharge — significantly dilutes mineral concentrations, producing a moderate rather than extreme hardness at the lower river reach.

With hardness at 112 mg/L, Metairie residents encounter moderate scale accumulation over time. Faucet aerators and showerheads develop deposits after several months — monthly cleaning with citric acid descaler keeps fixtures performing well. Dishwashers produce better glassware results with rinse-aid. Water heaters benefit from annual inspection for element scale. Jefferson Parish Water System consistently delivers water meeting all Louisiana DEQ and EPA Safe Drinking Water Act requirements throughout the Jefferson Parish service area.