We have a huge air compressor on the rig that blows air down the drill stem. The air comes back up the hole with enough force to move all cuttings up and out of the hole. If the well is producing water, the water will come too. Most of the time, we are actually pumping water into the air stream already, and we are really looking for an increase in the water. If we think we have hit water, we can turn off our water injection pump and check the flow of water with the air compressor alone.