This measurement is denoted in units of Ohm.m or Ohm.cm. Electrical resistivity is the most important parameter for the grounding grid design, integrating Ground Potential Rise Studies (GPR). The basis of grounding designs rely upon accurate soil models that take into consideration accurate electrical resistivity assessments.

Geotherm specializes in conducting electrical resistivity tests in laboratory, following the proven technique pioneered by the Electrical Research Department of Ontario Hydro. This methodology is an enhanced iteration of the 'ASTM G187-12; Standard Test Method for Measurement of Soil Resistivity Using the Two-Electrode Soil Box Method,' broadening the scope to encompass various density and moisture content ranges.