this is a 2003 twister horse trailer with sleeping quarters. this past weekend at a show i noticed a foul sulfur like smell coming from the taps when running water. happens in the sink at cooking area and sink in bathroom. we generally use bottled water for cooking and drinking so i cant honestly say how it taisted. it used for brushing teeth(i didnt notice any wired taste) and toilet, washing dishes etc. what causes this sulfur/egg smell and how can i get rid of it? do i need to put something in the holding tank? or can i flush the system with something to get rid of it? it stinks!!!! thanks for any help. anyone else experience this?