Hattiesburg Water Hardness & Quality Report (2026)

Hattiesburg, Mississippi, the Forrest County seat in southeast Mississippi — a major south Mississippi commercial, medical, and educational hub, home of the University of Southern Mississippi (USM) and William Carey University, the 'Hub City' (a regional retail and transportation hub for southeast Mississippi and southwest Alabama), and an important civil rights history site (the 1964 Freedom Vote and Hattiesburg Project) — draws its municipal water supply from local groundwater aquifers via the City of Hattiesburg Public Works Water Division. Water hardness in Hattiesburg measures 146 mg/L — classified as moderately hard.

Hattiesburg's moderate hardness reflects the south Mississippi Gulf Coastal Plain aquifer system. The Hattiesburg area draws from the Eutaw Formation and Cockfield Formation sands of the Mississippi Embayment — Cretaceous–Eocene calcareous-moderate sandy aquifer layers of the Gulf Coastal Plain. The Forrest County calcareous-moderate Gulf Coastal Plain geology includes: Eocene Cockfield Formation (calcareous-moderate sand with interbedded calcareous sands contributing dissolved calcium); Cretaceous Eutaw Formation (calcareous–siliciclastic mixed sand with moderate calcium content); and the Mississippi Embayment Oligocene Vicksburg Group (calcareous formation at depth contributing some hardness). The combination produces the moderate 146 mg/L at Hattiesburg.

At 146 mg/L, Hattiesburg residents encounter moderate scale accumulation. Faucet aerators and showerheads develop deposits after several months — monthly cleaning with citric acid solution is practical maintenance. City of Hattiesburg Public Works Water Division consistently delivers water meeting all Mississippi MDEQ and EPA Safe Drinking Water Act requirements.