Lake Fort Smith Water Treatment Plant (WTP) is a surface water treatment plant located in Mountainburg, Arkansas, and is the primary source of drinking water for Fort Smith customers. One of two drinking water plants owned and operated by the City of Fort Smith, this plant’s water source is the Frog Bayou watershed. Water is stored in the Lake Fort Smith reservoir.

Lake Fort Smith WTP was originally constructed in July of 1935. After several updates throughout the years, the present facility treats an average of 25.84 million gallons of water per day through a sequence of processes, including coagulation and flocculation, sedimentation, filtration, disinfection, and fluoridation.

Due to continued population growth in our area, the City of Fort Smith has begun the construction of a new 48-inch water transmission line that stretches 30+ miles from the Lake Fort Smith WTP to Fort Smith. Initially planned for completion in 2025, the overall project will provide the capability to supply water to all of the region’s water users at an increased rate of 70 MGD from 34 MGD

• Dedicated Employees: 11
• Watershed: Frog Bayou
• Source Water: Lake Fort Smith
• Average Daily Flow: 25.84 MGD (2023)
• Max Daily Flow: 36.04 MGD (2023)
• Permitted Design Flow: 40 MGD