I can confirm that too. I have one of the Ebac cheap dehumidifiers, and have given up emptying the tank! I drilled a hole in the wooden workshop floor (its up on brick sleeper walls) and put the drain tube through, so all the water runs to the outside world. No more coming in to find an overflowing tank!
I also recommend some background heating to keep things (and me) above the dew point. I have a s/h room-sealed wall gas heater, running on its low setting, and that keeps the chill off everything (again, including me). After about half an hour in the workshop (wood, lined with "insulation" board) I can turn off the gas heating, and my cussing and blinding at my mistakes (plus the heat output of the 1Kw motors on lathe and mill) makes enough heat to keep the place going!
Before this I had terrible damp/moisture problems for years - the roof timber and felt were so porous that the rockwool insulation just soaked rain up like a sponge, and then released it as fast as the dehumidifier could drink it! This was all cured by getting some swedish moulded and coated interlocking steel roofing sheets. Magic stuff! Though I can't recommend putting them on a roof in anything other than a dead flat calm, as they are big, and you can get blown off the roof very easily. Its also easy to dent the stuff by walking on the wrong bits when installing it, and unscrewing it and panel bashing the dents out is a time-wasting and soul-destrying pastime.....
Once finished, its fantastic - about £500 for an 18foot x 6foot lean-to shed - I mean workshop! It will outlast me, and the workshp is as dry as a bone - I don't even have to worry about the west end wall getting rain on it - the whole system beats any moisture ingess hands down, and I haven't installed ANY ventilation - but I DO open the door when doing a bit of silver soldering, or paint spraying! Cough spit cough!
Dave.