I have never used a water pan, but I don't remember why, or if there was a reason. I don't have a D model, so I use the cold smoke plate for the first part of the smoke, and have never thought about adding a water pan after I remove the cold smoke plate for the second part of the smoke when I turn up the temp. I think when in doubt, you can put a water pan in. I don't think it would hurt anything with bacon.