Laplace Water Hardness & Quality Report (2026)

LaPlace, Louisiana, in St. John the Baptist Parish — a major east Louisiana River Parishes community (LaPlace is the largest community in St. John the Baptist Parish — a significant east Louisiana community in the 'River Parishes' corridor along the Mississippi River between New Orleans and Baton Rouge; LaPlace is the center of the 'Cancer Alley' petrochemical corridor (the Mississippi River corridor between New Orleans and Baton Rouge is home to one of the highest concentrations of petrochemical plants, refineries, and chemical facilities in the United States; LaPlace and the neighboring communities have faced significant environmental and public health challenges from industrial air and water pollution)), a diverse St. John the Baptist Parish community with a significant African-American, Cajun-French, and working-class petrochemical industry population, adjacent to Reserve and Gramercy in the east River Parishes, home of the Bonnet Carré Spillway (the major Mississippi River flood control structure that diverts floodwaters to Lake Pontchartrain), and a community at the center of Louisiana's ongoing environmental justice debates — draws its municipal water supply from the Mississippi River via the St. John the Baptist Parish Water Division. Water hardness in LaPlace measures 108 mg/L — classified as moderately hard.

LaPlace's moderate hardness reflects the east Louisiana River Parishes Mississippi River supply's treatment characteristics. The Mississippi River at LaPlace–St. John the Baptist Parish carries Quaternary Mississippi River alluvial dissolved solids (varied calcareous content from multiple tributaries). Parish water treatment produces the moderate 108 mg/L.

At 108 mg/L, LaPlace residents encounter moderate scale accumulation. Monthly cleaning is recommended. St. John the Baptist Parish Water Division consistently delivers water meeting all Louisiana DEQ and EPA Safe Drinking Water Act requirements.