There is a white/transparent thread or worm like substance in my refrigerator water. The filter has been changed and many gallons of water run through with no change. Also, we unhooked the water line from the back of the refrigerator. When I re-connected it, the substance came out brown for a little while but is now back to white/clear. After the water line was re-connected, I could see the brown substance occasionally flowing through the water tubing that holds the cold water inside the refrigerator (behind the crisper drawers). Any idea what is causing this?
I would check the saddle valve on the basement cold water pipe. Just remove and check the water pipe. There might be sediment building up there.