An H2O scoop was a method of transportation over long distances, probably about one million miles in twenty seconds, used by the Judoon to transport locations from planets they had no jurisdiction (such as the Earth) over to neutral areas, such as uninhabited moons (TV: Smith and Jones) and deserts.
The H2O scoop process would start with plasma coils being placed around the location which was to be transported (which would cause an unusual static build-up in the area). A few days later a raincloud would form over the location, but nowhere else (Tish Jones pointed out that it was like a cartoon where there was a rain cloud over somebody's head). A short thunderstorm would follow, which ended when the rain from the storm rose back into the cloud. After a short period and a flash of light, the location would be transported.
In 2008, the Judoon used an H2O scoop to teleport Royal Hope Hospital to the Moon when they were hunting for the killer of the Child Princess of Padrivole Regency 9. Following her execution and the Judoon's subsequent withdrawal, the hospital was returned to its rightful place. Despite air running low and the Judoon having left an amplified MRI running, there were no further casualties. (TV: Smith and Jones) This incident similarly occurred in the parallel world created where Donna Noble never met the Doctor, except the lack of air resulted in only Oliver Morgenstern surviving this incident, and Sarah Jane Smith also died after having deactivated the MRI. (TV: Turn Left)