Approximately 7–15 million L of water are used per well [2]. The sand holds the cracks open to increase the amount of natural gas that can be extracted. The chemicals may include gels or butyldiglycol (typical 0.2 L/t water) that increase the viscosity of the fracking fluid to better transport the sand, foaming agents like CO2 and N2, to transport the sand, biocides to prevent growth of bacteria at organic components, acids like HCl, acetic acid, formic acid or boric acid to disintegrate the minerals of the rock formations, and anti-corrosion agents to protect the site when acid is added.
Approximately 50–70 % of the water solution is recovered. The remaining water stays in the ground. The recovered water is contaminated with chemicals and salts from the rock formation. It is either transported or directly disposed in treatment facilities.