First of all, the quality of well water depends on the source of groundwater and environmental conditions. In some areas, the groundwater layer is affected by pollutants, such as chemicals, heavy metals or pesticides and fertilizers produced by agricultural activities. Well water may be polluted if the well is located near these pollution sources. So we can't generalize. Well water with a depth of 100 meters is of high quality.
However, in some areas, the quality of groundwater may be relatively good. This usually happens in rural or mountainous areas far away from pollution sources. Groundwater in these areas may be naturally filtered, so the quality of well water is relatively high. In addition, some groundwater layers may also be protected, such as rock layers or specific structures of aquifers, to prevent pollutants from infiltrating into groundwater.
For groundwater with a depth of 100 meters, its water quality may be relatively pure because it is in a deeper underground layer. Deep groundwater is often protected by soil and rock layers and isolated from surface water, which reduces the impact of surface pollutants. Therefore, the groundwater with a depth of 100 meters may have higher water quality.
In a word, the quality of well water and groundwater is influenced by many factors such as geographical environment, pollution sources and protection measures. It cannot be generalized, and the situation in each region and place may be different. If you need specific information, it is recommended to conduct on-the-spot investigation or consult relevant local departments to get an accurate answer.