Sumter Water Treatment Plant

Sumter, SC

City of Sumter
Delivery Method

Project Description

Harper constructed the 4MGD Greenfield WTP and 3 associated deep wells for groundwater supply to the WTP. Adjacent to the existing WWTP, the scope of work included a two-story administration and filter building, a 1.5MG cast-in-place clearwell, two cast-in-place backwash tanks, high service pump station, associated chemical feed systems, 4 sedimentation basins, and dual media sand filters. The Harper Team self-performed the majority of the concrete work and process mechanical work on the project.

The project included a significant amount of architectural details. The administration building housed a training room, testing room, and filters. The City of Sumter uses this facility as office space as well as rental facilities for local functions.

A focal point for this project was the in-ground clearwell. Because the 1.5MGD cast-in-place structure sits below ground, water retention and leak testing were imperative. Harper followed strict quality standards to ensure the concrete was poured and cured correctly. Pre-pour sessions and post-pour testing ensured the owner received a clearwell with no leaks or permeability.


  • During construction, our quality control inspections indicated the potential for water to permeate the treatment basin and potentially enter the building. To ensure water did not seep into the building from the basins, the Harper team chose to add an extra layer of coating to the tank and building walls. Harper did not pass the additional time or cost on to the owner.
  • 2020 SC ACEC Engineering Excellence Award