I noticed several weeks ago that mine would do this too. I live in Illinois and we have central air, so I don't think it is the humidity. I actually use 2 different machines. Both of them are Pulmo-Aide, but one is newer and the other one is old (very old). I use the older one for albuterol and the newer one for Pulmozyme. What's strange is the hose that I use with the old machine does not get condensation in it but the newer one does. I usually just let my machine run with the hose attached (with the neb cup off) and let it dry out. They are both in the same room, so I'm not sure why one would get moisture in it and not the other.