I have put in humidifyers for years but mainly on city water. Well I put in a honeywell bipass humidifyer about 3 months ago and just got a call today that they have water in the furnace room. I go out and sure enough the clear plastic drain that I run off the bottom of the humidifyer is plugged up with scum that finaly plugged so it ran over inside the humidifyer and out around where the drain hooks up. Now I have always notice a little scum in some of the drain lines if you get a low point in it and I try keeping as much drop in the drain lines as I can to keep the lines dry inside when the humidifyer is not running. This water going to the humidifer is from a well with filters on the water coming into the house. They say they have not had any problems with water to refrigerator drinking water or ice maker or anything else with water. The humidifer is mounted on the return so the supply air is connected at the 6 inch hookup. So tell me , why does this one have such a problem with scum build up in the lines? Could it be that its running so much that the lines never really get a chance to dry , hard to believe being just off the bottom of the humidifyer its a straight drop down and the scum is there too. The scum is sticky and not water deposits.....any ideas ? If I were to filer it , I would think it would plug filter fast but I dont see why its that scummy if its not the water anyway but caused by the heat from the furnace with the water. Give me some ideas other than thats why you dont put in humifyers lol THANKS