Carrboro Water Hardness & Quality Report (2026)

Carrboro, North Carolina, in Orange County — a progressive university town adjacent to Chapel Hill and the University of North Carolina (UNC), known for its arts scene, the Cat's Cradle music venue, and its identity as one of the most liberal small cities in the Southeast — receives its municipal water from OWASA (Orange Water and Sewer Authority), which draws from University Lake (on Morgan Creek) and Cane Creek Reservoir (on Cane Creek in western Orange County). These two OWASA reservoirs are the sole water supply for Carrboro, Chapel Hill, and the UNC campus.

The moderately hard 115 mg/L hardness and TDS of 236.9 mg/L reflect the OWASA watershed's North Carolina Piedmont geological character. University Lake and Cane Creek Reservoir drain the Orange County Piedmont — terrain underlain by the Triassic Deep River Basin formations (Chatham Group shale and sandstone — calcareous continental redbeds) in the University Lake watershed, and the Carolina Slate Belt (Neoproterozoic metavolcanic and metasedimentary rocks — low carbonate) in the Cane Creek watershed. The Triassic calcareous redbeds of the Deep River Basin contribute moderate dissolved calcium and bicarbonate to the University Lake supply, while the Carolina Slate Belt provides a softer baseline for the Cane Creek contribution. The blended OWASA supply produces consistently moderate hardness throughout the Carrboro-Chapel Hill service area.

At 115 mg/L, Carrboro's water is moderately hard — scale builds in kettles and appliances over months, dishwashers benefit from rinse aid, and faucet aerators need periodic cleaning. Quarterly descaling is appropriate. The PFAS level of 6.1 ppt warrants a certified drinking water filter — the Haw River (the Cane Creek-Morgan Creek drainage basin downstream context), Research Triangle Park's pharmaceutical and chemical complex, and the broader Orange County Piedmont industrial corridor contribute to Carrboro's PFAS readings.