Corsicana Water Hardness & Quality Report (2026)

Corsicana, Texas, in Navarro County in north-central Texas southeast of Dallas — historic site of the first commercial oil discovery in Texas (1894) and home to the Corsicana oilfield that launched the Texas petroleum industry — receives its municipal water from the City of Corsicana Water Utilities, drawing from Richland-Chambers Reservoir on the Trinity River system and supplementary supply from Lake Navarro Mills in Navarro County. These reservoirs impound runoff from the rolling East Texas Blackland Prairie terrain of north-central Texas.

The hard 189.5 mg/L hardness and TDS of 452.8 mg/L reflect the Blackland Prairie's characteristic Cretaceous carbonate geology. The watershed draining into Richland-Chambers Reservoir and Lake Navarro Mills crosses the Blackland Prairie's dark heavy clay soils developed over Cretaceous Austin Chalk and Taylor Marl — highly calcareous marine chalk and marly limestone deposited in the Cretaceous Western Interior Seaway. These chalky formations are the same geology producing consistently hard water across the DFW metroplex corridor and extending southeast through east-central Texas. Navarro County's exposure of these formations produces a reliably hard water supply.

At 189.5 mg/L, Corsicana's water is hard — consistent with the north-central Texas norm for cities drawing from Blackland Prairie reservoir systems. Scale forms in kettles and coffee machines within weeks, dishwashers benefit from rinse aid, and bathroom fixtures require regular acidic cleaning to prevent calcium ring buildup. Descaling appliances every six to eight weeks is the practical cadence. The PFAS level of 7.1 ppt warrants a certified drinking water filter — the DFW-to-Corsicana industrial corridor and Navarro County's petroleum production history contribute to the regional PFAS baseline in north-central Texas water supplies.