We have a 20' dug well (I don't live all that far from chamlover) and I choose not to use our water. I buy bottled water (though no guarantees there either). We live on a clean river and a few acres of conservation land, but that is still no guarantee. We have high copper and iron and even though we use a filter, with all the spraying and drinking Cyrus gets it is not worth the risk and, as rcmike said, there is always the possibility of bacteria. I notice a change in the water (shower) after rain or or heavy snowmelt (like right now).
Even if you have an artesian I would have your water tested. Here in NH there is a swath of land area through the state where high levels of arsenic and mercury were found (in drilled/artesian wells). Of course, this will vary where you live so I would just get it tested. What our bodies can handle and what our animals can handle are considerably different.