Biloxi Water Hardness & Quality Report (2026)

The City of Biloxi Public Works System (PWS) supplies drinking water to over 46,000 residents across Biloxi, Mississippi, serving approximately 24,243 connections in Harrison County. The service area includes downtown, East Biloxi, the Peninsula, and areas near Beau Rivage Casino. Water is sourced exclusively from groundwater wells tapping the Pascagoula Formation, Graham Ferry Formation, and Miocene Series Aquifer. Standard groundwater treatment includes disinfection and fluoride addition for dental health; the supply relies entirely on coastal aquifers with no surface watershed or reservoirs involved.

The Pascagoula, Graham Ferry, and Miocene Series Formations form a multi-layered groundwater system of sands, gravels, and limestones from the Miocene epoch (roughly 23–5 million years ago). This Cenozoic-era geology imparts a hard character to the water through natural dissolution of minerals from Mississippi's limestone bedrock and sandy coastal soils, leading to moderately mineralized groundwater with elevated dissolved calcium and magnesium typical of the Gulf Coast subsurface.

At hard water levels, scale buildup occurs in pipes, water heaters, dishwashers, and washing machines, reducing efficiency and lifespan. Soap lathering is less effective, increasing detergent use, and spotting appears on dishes and fixtures. Regular descaling of appliances and hot water systems is advised; a whole-home water softener is recommended to mitigate these effects and protect coastal plumbing. Recent City CCRs confirm compliance with EPA standards, with fluoride at 2.9 ppb (range 0.5–2.9 ppb); independent assessments flag trihalomethanes, haloacetic acids, and arsenic above stricter health guidelines, though within legal limits.