Fort Smith Water Hardness & Quality Report (2026)

Fort Smith Water Utilities serves over 87,000 residents in Sebastian County, Arkansas. The utility draws primarily from surface water sources: the Frog Bayou Watershed, stored in Lake Fort Smith and treated at the Lake Fort Smith Treatment Plant, and the Lee Creek Watershed, stored in Lee Creek Reservoir and treated at the Lee Creek Treatment Plant. Water is also supplemented from the Arkansas River and underground aquifers. The Arkansas Department of Health has assessed these sources as having low to medium susceptibility to contamination; since March 2016 the utility has added fluoride to maintain 0.7 mg/L per state requirements.

The Frog Bayou and Lee Creek watersheds are situated in the geologically diverse Arkansas River Valley, characterized by Paleozoic-era limestone and sandstone formations, including chert-bearing layers. These sedimentary rocks influence water chemistry as surface runoff and infiltrating groundwater dissolve minerals during transit. The soft supply reflects limited mineral dissolution in these watersheds — limestone contact adds moderate mineralization without extreme hardness, producing a soft to moderately mineralised profile.

As a soft water supply, Fort Smith experiences minimal scale buildup in pipes and appliances, preserving water heater efficiency and extending lifespan. Faucets and fixtures show little limescale, and soap lathers effectively without excess detergent. A water softener is not recommended and could unnecessarily alter the naturally balanced chemistry. Water earns a 'C' grade for health guidelines per independent assessments, with 7 contaminants — including chromium (hexavalent), trihalomethanes, and bromodichloromethane — exceeding health advisories; disinfection byproducts form during chlorination treatment of river and reservoir water. Fluoride is adjusted to 0.7 mg/L.