Drinking Sewer Water

My bathroom smells like sewer. It always has, since I moved in. I used to think that it was the people that lived there before us. I thought perhaps they had horrible toilet habits. I could never get the smell out, no matter what I did. Then I was brushing my teeth, and smelled that sewer smell again. I thought maybe it was something in the drain causing it to smell when the water hit it.

The water itself is crystal clear, cold and refreshing. It didn't take long before I realized that it's the water itself that smells like sewer. I wanted to puke. I brush my teeth in the kitchen sink now. For some reason, the smell has not reached the kitchen (it still smells sort of bad though). We filter all of our water too.