There are a nearly limitless number of attributes and contaminates that waters can be tested for. Regulatory requirements may dictate the required analysis. For your investigative purposes, it's up to you to choose what analysis you'd like us to perform. We can suggest analysis based on your concerns, apparent problems as well as your well and area history.
Common problems with local well waters we recommend routine testing for include: coliform presence/absence, arsenic and nitrate. We recommend routine testing for lead/copper in older homes (pipe corrosion). Bacteria contamination is the most likely cause of immediate gastro-intestinal sickness. Contaminations such as heavy metals pose a more cumulative concern.
The Department of Health has established Maximum Contamination Levels (MCL) for most drinking water analysis. These are the maximum levels the Department of Health has determined to be safe and have been established through analyzing various studies on toxicity and heath effects. Exactly what level is "safe" can be contentious and some people are more sensitive and susceptible to certain contaminates than others. Consult your physician for specific concerns of a result's affects on your personal heath.
If you live in an agricultural area, nitrate, coliform bacteria and pesticides/herbicides may be of particular concern.
If you live near a landfill or industrial area, heavy metals, volatile organic compounds, pH and sulfate may be suggested.