If your water smells like rotten egg or sulphur then I guess you have to confirm it in hot or cold water.
1. Run a hose bib or tap as close to the well as possible to fill a bucket and notice if there are odurs.
NOTE: If it smells like rotten egg this is hydrogen sulfide gas
If your water smells like oil this can be from manganese
If your water smells like cucumber or sewage this is as a result of iron or sulphur bacteria
Do same for hot water to confirm if you will notice same odur or not
However to treat odurs in well water use a chlorinator or inject hydrogen peroxide to kill odurs