My fiance and I purchased a 1971 home on 8/23/19 with a well drilled 1971 as well. Water test was done by the seller, I received a confirmation but not the technical results. I could taste moderate amounts of iron and sulfur in the raw well water. I installed a whole home filter (Omnifilter sediment - 5 micron) which cut out most of the taste, the water softener took care of the rest. Installed new water heater on 8/24/19.

Sequence of water flow: Well > Pressure tank > sediment filter > water softener > Water heater > out to home

We were out of town at my folks cabin this last Friday evening to Sunday afternoon, our water quality went to hell on our return. Only the hot water is affected, the water reeks of sulfur. It went from perfect to rancid in less than 48 hours. Could this be a bacterial infection in the water heater? I also noticed the sediment filter housing which is a clear plastic has a brown film.

Has anybody experienced something like this before?