The vast majority, upwards of 90 percent of flow-back water (brine) is recycled and reused for future well completion activities. When the water returns to the surface, operators can either treat the water at the wellsite and store it for future use, or transport the water to a centralized water treatment facility where it can be recycled for future use. Operators can also send flow-back water to U.S. Environmental Protection Agency regulated Class II injection wells.