Here in Costa Rica you will find that most "local" drilling companies almost always drill water wells in this form. The problem arises in that they are not capturing the true amount of water that lies beneath the alluvium and in the hard rock basalt. There are various things to consider when drilling a shallow alluvium well, but the most important factor is that your well is going to be affected by the seasonal changes each year. i.e. (low rainfall=low well yield)

In addition, Costa Rica has no licensing laws pertaining to its drillers. Therefore, a lot of drillers are not educated in proper well installation techniques such as proper grouting procedures to ensure that no harmful substances enter you water well. Yes, these wells are economical, but the old saying rigs true.

"You get what you pay for!"