The carbohydrates and proteins that our bodies use as food are metabolized and transported by water in the bloodstream. No less important is the ability of water transport waste material out of our bodies. The natural water cycle or hydrological cycle is the means by which water in all three forms—solid, liquid, and vapor—circulates through the biosphere. Evaporation of water is a major factor in hydrologic systems. This chapter discusses the need for watershed management on a multiple barrier basis and provides brief overview of the range of techniques and approaches that can be used to investigate the biophysical, social, and economic forces affecting water and its use. It focuses on surface water and groundwater hydrology and the mechanical components associated with the collection and conveyance of water from its source to the public water supply system for treatment. The chapter also focuses on the components that make up the well itself.