A recent NASA test involved hundreds of thousands of gallons of water being pumped out of its immensely powerful launchpad cooling system.
Used to reduce extreme heat and energy generated by a rocket launch, last week the Ignition Overpressure Protection and Sound Suppression water deluge system at Kennedy Space Center's Launch Pad 39B was tested, sending water about 100 feet in the air.
The test is part of preparations for the launch of the Exploration Mission-1 and subsequent missions. The Exploration Mission-1 will serve as a test for the new Space Launch System and the new Orion spacecraft, built to carry astronaut crews on deep space missions. It is expected to launch in June 2020.
Below their video post on Youtube NASA noted: "Modifications were made to the pad after a previous wet flow test, increasing the performance of the system. During launch, this water deluge system will release approximately 450,000 gallons of water across the mobile launcher and Flame Deflector."