This Implementation Guide has been prepared to describe how soil washing can be used to treat per- and poly-fluoroalkyl substances (PFAS) impacted soil. It will describe the basic principles and capabilities of soil washing and the applicability of soil washing for different sites. This Implementation Guide will then describe the steps required to implement soil washing: from the initial feasibility study and scaling up bench scale treatability studies to a full-scale treatment system. Soil washing can be used to treat a variety of chemicals of concern; however, this Implementation Guide will focus on the treatment of PFAS impacted soil and does not include discussion of treatment of other chemicals of concern.