We recently received an inquiry from Hannah in Virginia who asked, "We have just bought a house with a "deep" well in [deleted for privacy reasons&91; County VA. We want to test the water for contamination and safety so can you please recommend the appropriate test kit."
In our experience 'deep' wells tend to have better quality water than 'shallow' wells which have a greater risk of seeing contamination from pollution activity on the surface.... but that does not mean contaminants cannot infiltrate deep wells, too.
We suggest starting your investigation by contacting your local health department and asking them for information on contaminants they have heard about affecting the quality of well water in the area.
If they do not immediately warn you of known 'issues', then a kit such as the SenSafe Water Quality Test Kit, WaterWorks COMPLETE Water Test Kit, or WaterSafe Well Water Test Kit should work just fine.
If, however, your local health department did know of 'issues', we suggest having your water tested by a professional laboratory such as National Testing Laboratories that offers much more comprehensive testing packages.