My roommate has no common sense. She put down area rug over recently shampooed carpet?

Do not go behind her back.  If you do then you are in the wrong.

Immediately   Knock in her door and tell her, that carpet is not dry and if the carpet gets ruin then I have to forfeit my deposit. Smile be cheerful. I  am sure you don’t want that to happen and I am sure you wouldn’t want a moldy carpet in your room. Then walk right in  with a fan and Say Let’s get this dry for you ASAP . Move your stuff and I will aim the fan directly on it.  

Explain. I know you may have never cleaned carpet before. It took my room over night to dry properly.  

If she gets nasty with you, say I am so sorry but I must insist we get the carpet dry.  I will not loose my deposit money.  

I have rarely seen room mates get along. There are always issues.  

Does she has a lease? Does she any contract with you or the owner? Can you survive without a roommate for a month or two while you search for another? 

Try to reason with that idiot. Ask her to remove the plastic matt and area rug UNTIL The carpet is completely dry.

If she bucks you ...Assert yourself and let her know that it's your deposit that is in jeopardy and if she insists on not allowing the carpet to fully dry to your satisfaction, she is welcome to give you half of the deposit immediately. Otherwise you are going to removes her plastic mat and area rug immediately.Grow a back bone and protect yourself from any potential rug issues.

Do what you have to to protect your deposit. if she does not like it, tell her to move out.

UMMMMM..... Did you ASK her or just decide to do it when she wasn't there?  If you asked and she agreed, then ask her to put a fan on the damp place overnight.  If you didn't, then you invaded her private space and made it so she cannot use it effectively and then you are fussy over the way she is using it after you did something without permission.

Miss Manners would say that ... "after you give a gift it belongs to the recipient and they can do with it whatever they wish."As far as the mold and bacteria growing...Um.. If you did the shampooing right, then there should be no mold and bacteria to fester and grow.

And if you take your roommates items out of their room and put them in your room that is theft.  It does not matter that you never removed them from the apartment...if you go into a room where the inhabitant expects a reasonable amount of privacy AND you REMOVE items that belong to that person...that is sketchy...but if you then put them in a place that YOU stay in and expect a reasonable amount of privacy....that is theft.

It would be the same if you knew your roommate had $100 on their bed and you went in and took it and put  it in your closet to 'protect ' it.

THEFT.

You can stop the drama now if you choose.  Do not escalate this.

You should have anticipated this and sucked up all the water so good that you were confident there would not be a problem.  Or put a heater and fan in the room and stayed with it.   Wait till tomorrow and check the carpet again.   If it is still wet tell her that the coverings are preventing the carper from drying.  Bacteria, etc.  Offer to help her remove her stuff.  But, do not touch her stuff without her consent.  After a month or so, ask her to move.   You might point out to her that she is the one having to live with the wet carpet.

I really wish you'd not follow me, Pearl. You answer every  question and the answers are always entirely useless. 

i wouldnt do her carpet again if shes going to be like that