Marshall Water Hardness & Quality Report (2026)

Marshall, Texas, in Harrison County in the East Texas Pineywoods near the Louisiana border — a historic city known as the "City of Lights" for its Christmas light displays and home to Wiley College — receives its municipal water from the City of Marshall Water Utilities Division, drawing from Lake O' the Pines on Big Cypress Creek in Marion County and regional reservoir supplies. Lake O' the Pines is a large US Army Corps of Engineers impoundment that provides water supply, flood control, and recreation for northeast Texas.

The hard 190.5 mg/L hardness and TDS of 455.8 mg/L reflect the East Texas Pineywoods' moderate carbonate geology. Big Cypress Creek and its tributaries drain the rolling Piney Woods landscape of northeast Texas — an area underlain by Cretaceous Woodbine Formation sandstones transitioning eastward into more calcareous Eagle Ford Group chalks and marl. While the East Texas Pineywoods are less carbonate-rich than the Blackland Prairie to the west, the Cretaceous marine formations throughout Harrison County contribute meaningful calcium and magnesium bicarbonate to watershed runoff, producing consistently hard water at the Lake O' the Pines supply.

At 190.5 mg/L, Marshall residents deal with hard water familiar throughout northeast Texas. Scale forms in kettles and coffee machines within weeks, dishwashers benefit from rinse aid, and bathroom fixtures develop calcium rings over time. Water heater efficiency declines without annual inspections. Descaling appliances every six to eight weeks is the practical schedule for Marshall households. The PFAS level of 7.1 ppt warrants a certified drinking water filter for daily tap water consumption — northeast Texas's oil and gas operations and industrial activity contribute to the regional PFAS baseline.