Hydraulic fracturing, or fracking, is used to extract natural gas or oil from deep within the earth, specifically from shale, which is sedimentary rock composed of clay. A tunnel is drilled 1-2 miles deep to reach this shale, and then fracking fluid, which is made primarily of water, is pumped into the tunnel at high pressure to shatter the rock, releasing the gas (U7L2, Click on Environmental Impacts of Fracking Transcript). About 2-5 million gallons of water are needed to create the fracking fluid for one well, which puts stress on local water supplies, potentially decreasing the quantity of water available for everyone to use (U7L2, Click on Environmental Impacts of Fracking Transcript). Furthermore, used fracking fluid contains additional chemicals and radioactive materials that can leak back into water supplies, posing a threat to water quality. This would worsen the quality of water available for everyone to use, as contaminants could infiltrate rivers and aquifers (U7L2, Page 7).
Source: Unit 7 Lesson 2, Page 3 and 7