Anyone know solutions to remove humidity?

Mix paint with silica gel, then paint your house with it two to three layers. Humidity gone permanently.

dehumidifier.

If the bathrooms are not already vented to the outside (and I found out the hard way that windows don't count) you may have to install some sort of fan that vents to the outside -- that means someone comes in to chop the hole, you have a Master Electrician come in and install and wire the fan unit, and then have a handyman repair the hole.

I think this cost me a few hundred bucks in my downstairs bath (suburban house) but it made a tremendous difference. The thing is because you have water near electricity, you really really do want a Master Electrician to do it -- don't skimp here.

ali r.
{downtown broker}

If the room's not below grade (i.e. basement), I wouldn't be satisfied with "no mold or mildew present". I'd try to find a leak in the walls, sweating pipes, etc., where mold or mildew is growing, and eradicate the underlying source of the problem. See if your building's superintendent, management co. or board can advise you.