Groundwater Treatment Facility Posted on April 12, 2016December 21, 2023 by Weston & Sampson (A) Jamestown Groundwater Treatment Plant Weston & Sampson was the prime contractor for a new $3.2M groundwater treatment plant, completed in 2011. BACK Looking for assistance with your Construction project? How can we help? Posted in Construction, Treatment Facilities and tagged Jamestown, RI.