I am currently at my wit's end trying to diagnose gurgling that happens at my kitchen sink when the dishwasher drains. The drain is not clogged or plugged at all. We also have a RO filter and it gurgles while the tank is refilling. Could these two sounds be related? We have been told that "gurgling is normal" but I refuse to believe it! I have never had this problem at any house I have lived in. Any help would be appreciated. TIA.