Mine (95 EVC) had a foul taste from day one...a plastic/chemical-like taste. I tried a variety of remedies: Bleach, vinegar, baking soda, hot soapy water, and likely several other things I've forgotten. I called Winnebago and followed their recommendations too. I'd soak these concoctions for days, driving around making sure the liquid splashes hit every nook and cranny. Some times the taste would disappear for a short time...but it always came back. I couldn't drink it. The warranty was still valid so, Winnebago reluctantly agreed to put in a new tank and hoses. The water was slightly better....but only for a short time. By then, the warranty expired and Winnebago wanted nothing to do with me.

At any rate, I simply gave up using the "fresh water" tank for potable water and started carrying that in separate 1 gallon glass jugs. I do use the water in the "fresh water" tank for washing dishes and taking impromptu showers in the back.

Sorry that I have nothing positive to add here other than my experiences. Best of luck.