Liner Integrity Surveys can be performed on bare geomembranes as well as geomembranes covered with earthen materials, water or wastewater. Electricity is introduced above the geomembrane and grounded to the subgrade below the geomembrane. Since geomembranes are electrically isolative, the methods track the electrical current travelling through holes in the geomembrane. The current is tracked differently depending on whether the geomembrane is covered or exposed.
For bare geomembranes, water is sprayed onto the geomembrane to carry the applied current, or a high voltage is introduced above the geomembrane to create an electrical arc in the presence of a leak.