landlord/tenant issues

My family and I rented a house in February, and quickly realized there was a problem with the plumbing. After informing the landlord, she came and looked and told me to tighten the knobs in the shower. We received our first water bill, for twice the usage as we've ever used, and I notified the landlord again that there was an issue, she said call the water dept. My kids started getting sick last month, and while I was cleaning and disinfecting EVERY surface I could get my hands on, I found mold, or mildew, in 2 closets. Upon looking closer, I realized the area where the mold, or mildew, was found had been painted over. Not the entire closet, just a 1ft sq area. I called the landlord again, who finally called a plumber to come to the house. Plumber says a drainage line under the house is rotten. Landlord calls me on the 1st and starts cussing me, I remind her, as I've reminded her every month since Feb, that I get paid on the 5th, and I always pay the late fee without question. She has accepted this the last 3 months without comment. Plumber was due Monday, never showed up, until my husband called the landlord and threatened to call the city health office. There's so much more to this story, but what I want to know, because I'll likely be looking for a new home, is this: if she knew the house was uninhabitable because of the mold and mildew damage in the walls and the condition of the plumbing under the house, and I'm guessing she was aware, mainly because the house was covered in moth balls and the earlier patch job I mentioned, is she obligated to return my security deposit and rent I've already paid? Our lease states that "the premises, including the grounds and all buildings and improvements, are, at the time of this lease, in good order, repair, and a safe, clean, and tenantable condition"