Jonesboro Water Hardness & Quality Report (2026)

Jonesboro, Arkansas, the Craighead County seat in northeast Arkansas — the largest city in northeast Arkansas and home of Arkansas State University — draws its municipal water supply from Lake Frierson (an impoundment near Jonesboro in Craighead County) and from local groundwater wells accessing the Mississippi River Alluvial Aquifer (the Quaternary alluvial aquifer of the Arkansas–Mississippi Delta plain) via the City of Jonesboro City Services Water Division. Water hardness in Jonesboro measures 201 mg/L — classified as hard.

Jonesboro's hard supply reflects the northeast Arkansas Mississippi Alluvial Plain's water chemistry. The Mississippi River Alluvial Aquifer underlying Craighead County — part of the vast Delta Alluvial Plain — consists of Quaternary sand and gravel deposited by the ancestral Mississippi, Arkansas, and St. Francis Rivers. These alluvial sediments contain calcareous gravel from the Ozark Plateau limestone and dolomite drainage (reworked Ordovician Gasconade Dolomite, Mississippian Burlington Limestone, and other Ozark carbonate formations carried southeast by the ancestral rivers). Groundwater from these calcareous alluvial gravels produces hard supply throughout the Arkansas Delta. The Lake Frierson surface water component is also influenced by the calcareous Delta plain terrain.

At 201 mg/L, Jonesboro residents face significant hard water challenges. Scale deposits form rapidly on faucet aerators, showerheads, and appliances — monthly descaling with citric acid solution is essential maintenance. City of Jonesboro Water Division consistently delivers water meeting all Arkansas DEQ and EPA Safe Drinking Water Act requirements.