Water drilling.

There are many different DIY well drilling machines. SO I guess the first question would be how deep do you anticipate needing to make the bore hole The next question would be how you plan on using the water if it is just for watering your lawn or small home garden then you may be able to get away with the first water bearing strata which is called surface or near surface water. Depending on where you are located a bore hole of this nature could be quite shallow and could be done by what is called jetting or jet drilling done either by a high volume medium pressure water pump of about 10 to 35 Hp or an air compressor like one that would be used to power a jack hammer, using a long pipe forced in the ground with a special made jetting bit with directionaly mounted nozzles these are hard to control the bore diameter as well as maintain a nice vertical shaft without the aid of a rotational drive
Next you could modify a 2 man post hole digger to travel up and down a simple derrick you would need a rotary water swivel some short lengths of threaded pipe (length depending on how high you make your derrick a 2 to 3 inch centrifugal water pump up to 10 HP and a drill bit an air compressor could be used here in Lieu of the water pump it just needs to have enough volume to lift the fines out of the bore hole.
If you are needing or wanting to drill for water which will be used for household purposes it may have to be much deeper if over 35 to 50 ft with a 6" minimum diameter bore hole your equipment will need to be larger I have personally designed and built drill rigs capable of drilling a 8" bore hole to a depth of 6000 ft but you are not talking about a major rig such as that I am sure.
I imagine that the Admin will move this to the tools in process section to get more input