When I worked remotely on an island off the top of Australia fresh water was drawn from the aquifer. Studies were done of the aquifer and maps drawn up. In Thailand 'the Department of Certain Things' (I don't know which department) has done extensive aquifer mapping and if you find the correct department you will/may be able to buy copies of the aquifer maps in your area, or, search Ai for your regional aquifer. This will tell you the geography, depths and composition of the aquifer, so with your well water test and this info. should help. Initially, when I built the house, my well water was crystal clear but when exposed to the air the Fe in the water precipitated out and left a brown stain until I tested and installed the correct filters. Now I have installed a chlorine pump initially my pool went brown with all the rubbish in the pipes.