Bentonville Water Hardness & Quality Report (2026)

Bentonville, Arkansas, the Benton County seat in northwest Arkansas — the world headquarters of Walmart (the world's largest company by revenue), a rapidly growing affluent tech and retail corporate hub, a nationally recognized cycling destination (the Oz Trails mountain bike network), home of the Crystal Bridges Museum of American Art (one of the finest art museums in the United States, endowed by the Walton family), and one of the fastest-growing metro areas in the United States — draws its municipal water supply from the Ozark Plateau karst aquifer via the Benton–Washington Regional Water Distribution District or Bentonville Water Utilities. Water hardness in Bentonville measures 193.5 mg/L — classified as hard.

Bentonville's hard supply reflects the northwest Arkansas Ozark Plateau's calcareous karst geology. The Springfield and Salem Plateau aquifer systems at Bentonville–Benton County draw from: the Mississippian Boone Formation (calcareous chert and limestone — the dominant formation of the Ozark Springfield Plateau, extremely calcareous); the Devonian St. Peter Sandstone (minor calcareous contribution); and the Ordovician Gasconade Dolomite and Jefferson City Dolomite (highly calcareous dolomite of the Salem Plateau — among the most calcareous formations in the Ozark Plateau sequence). The Boone Formation and Gasconade Dolomite karst dissolution produce the hard 193.5 mg/L at Bentonville.

At 193.5 mg/L, Bentonville residents face regular hard water challenges. Scale deposits form on faucet aerators, showerheads, and appliances within weeks — monthly descaling with citric acid solution is standard maintenance. Bentonville Water Utilities consistently delivers water meeting all Arkansas DEQ and EPA Safe Drinking Water Act requirements.