I just moved into a house that is about six years old. The master bathroom has a smell that I can only describe as "musty". I've cleaned every inch of the bathroom, as well as the walls which caused the smell to go away until the next use. The smell is strongest a few minutes into showering and seems stronger towards the ceiling. The ventilation fan is clean and works well but is not centered in the bathroom, which causes noticeable condensation to form on the wall farthest from the fan and the walls above the shower itself. I installed a timer on the fan switch to allow longer ventilation after I leave... There is no mold or leaks anywhere. The water in my area is very hard, could this cause the smell?? Also, a co-worker suggested replacing the anode in my hot water tank as that can cause the water to smell, is there any truth to that?? Any suggestions would be appreciated as the smell is beginning to take over my house! (well at least the top floor... )

If you had a bad anode rod in your water heater you would have smelly water all over your house.
Since you notice it more in then shower let's start with the drain.
Most bad odors in bathroom drains come from rotting hair mixed with grease from the soap. Try this. Remove the two screws holding the strainer. (TIP; put the screws in the soap dish before they get lost down the drain.) Shine a light down there and with a bent coathanger fish out any hair that may be hiding down there. Then pour a 1/2 gal. of bleach down into the trap and let it set over night. Next morning flush the mess down with 2 large pans of boiling water, (this is important). The bleach will dissolve the hair and make it slippery and the boiling water will melt the grease and get the mess out of your drain. Smell better now? Cheers TOM

Thanks for the reply. I tried the bleach and boiling water. That was a good trick and needed to be done but was not the source of the smell. I'm going to install a larger fan and crawl into the attic and check above the bathroom... Any other thoughts??