I have a GE side-by-side refrgerator that is less than a year old. Very soon after installation, the filtered water from the dispenser started tasting moldy. I replaced the filter, twice, and the problem wasn't fixed. I then bypassed the filter and still the problem wasn't fixed. The water from the tap is fine. If I remove about 30 oz. from the system, the water tastes fine but is not cold. The ice cubes also taste moldy. All of the lines to the unit are copper and new. I think there is mold in the lines and the longer the water sits, the worse it gets.

Are you on well water or a chlorinated city supply? It sounds as if iron reducing bacteria have grown in the tubing. You can try a pinch of bleach to sterilize the tubing followed by a rinse with the water supply. This will not hurt the filter or the tubing as city water is chlorinated. If the filter has carbon inn it (to remove bad tastes) the carbon will remove the chlorine put in by the city and bacteria can grow.