Flame,
The sulfer smell in your well water is caused by high levels of hydrogen sulfide gas that is dissolved in the cool water within the well. The gas is released as the pressure and temperature changes as the water is pumped to the surface. The source of the gas is Coliform bacteria growing in the well and on the pipe and pump. It will occur more readily on a well that is not used much. The management is "shocking" the well with Chlorox much like shocking a swimming pool. It typically takes care of the problem. My well had this problem and one "shock" handled it completely. There are protocols to do this posted on internet sites and on You Tube.
