One of the primary means of drilling a well used in undeveloped countries to drill wells is the Baptist Method. It requires a little water and a lot of manpower. A drillpipe with a pointed bit and a valve that only permits upflow is used to push through the layers of earth until water bearing sand is reached. On the downstroke, one driller forces the drillpipe down. On the upstroke, others using a pulley and a rope, pull the pipe back up to prepare for the next downstroke. On the downstroke, water and mud is pushed up and out of the pipe. A manual water re-circulating system is used. Bentonite is mixed in the water to keep the borehole open. There is a great video, posted on YouTube by josephstocker, that demonstrates the method. Unfortunately it has no sound. You may need to play it a couple of times to pick up on the details.
A derrick is constructed and a pulley is mounted. A posthole digger is used to start the hole. A pit is dug next to the hole and a small trench is dug between the hole and the pit so water can be re-circulated.
The digging is accomplished with a valve based drilling system. The drillpipe has a valve near the bottom end that permits water to flow up but not back down. The actual digging is done with a drillbit pointed piece of metal that looks kind of like an arrowhead. This drillbit is a part of the valve. As the apparatus is driven into the ground, the mud/water/bentonite solution is forced out the top of the pipe.
On each stroke of the pipe, pne person pushes the pipe down while others pull it back up using a rope and the pulley. When the pipe is worked completely into the ground, another piece of pipe is added and the process is repeated. The bottom piece of pipe is steel. The next section and all subsequent sections are PVC.
After sufficient depth is reached, the drillpipe is removed and a well screen and well casing are installed.
I found several mechanized adaptations of the Baptist drilling method. Each utilize some type of motor or engine to pull the drill stem back up. This video by beamsclan on YouTube best demonstrates how a motorized system can make the technique much easier and faster.
MOTORIZED BAPTIST WELL DRILLING
The video below, posted by beamsclan, shows how to make a drill bit to use in the Baptist method.
CONSTRUCTING A DRILL BIT FOR THE BAPTIST METHOD