Years ago when I was still drinking tap water, our water had an awful smell to it for two weeks and so I drank bottled water.  Finally after a couple of weeks of this, I called the water department to find out what was going on.  The answer I received was, “It’s OK.  It’s just sewer gas that has backed up into the water lines.  But the water is safe to drink.”  I can’t remember how I replied, but I do remember thinking, “No, it’s NOT OK to have sewer gas in my tap water.  I don’t care what you say.”  We never would have known about it had I not called.  That makes me wonder what all is in our water that we never know about.  Since then, our whole family has been drinking bottled water.  (My husband was already drinking bottled water.)  Now we drink distilled water.  There’s no way sewer gas can get into that!