Method for drilling a borehole and wet boring tool

Wet-drilling tool (10) comprises a jacket (15) having a drill bit (8) on its under side and a cover (11) on its upper side provided with at least one passage device for the passage of a liquid, a collecting container (6) for collecting drillings, and a pump device. The passage device has a valve element allowing fluid flow in the direction of the interior (3) of the jacket through the passage device and blocking fluid flow in the opposite direction. The passage device has a tubular dome (20) with at least one lateral inlet opening (21) above the collecting container. The dome is arranged coaxially to the jacket on the cover and has on its upper side a connecting rod connection (28) for attaching a boring rod. Independent claims are also included for: (1) Drilling system comprising the above drilling tool; and (2) Process for creating a hole in the ground using the above wet-drilling tool.