What is one of the most common reasons for the contamination of wells drilled through rock?

One of the most common reasons for the contamination of wells drilled through rock is the failure to seal well casings properly. Proper sealing is crucial in protecting the well water from surface contaminants and ensuring that water does not enter from layers of soil or rock that may contain harmful substances. When well casings are not sealed correctly, there can be pathways for pollutants, such as fertilizers or sewage, to seep into the well. This not only increases the risk of contamination but can also affect the overall quality of the water drawn from the well. Properly sealing the well casings helps to maintain the integrity of the water supply by preventing potential contaminants from infiltrating the well system.