"Kate" wrote:

I have a Kohler toilet tank in one of the bathrooms that sweats so much that
it forms small puddles on the tile floor.

An aquarium heater can help.

I've been told that it is because the humidity is too high in my house and
that I should get a dehumidifyer. That is out of the question, I cannot
afford one.

You might run an $80 window AC indoors for very efficient electric heating.

Nick