Carpet Cleaning

I now live in a two story home and because the ppl that lived in this house before us, were pretty much pigs, I have to get the carpets cleaned. Dirt is quite visible on bare feet. (EWWWWW!) Anyway, my concern with using steam cleaning was that it would get the subfloor wet. Being in the southern part of Texas, one needs to pay attention to excess moisture in the house. I have thought about doing the dry cleaning method, but that won't work either cuz I want the dirt UP and OUT. LOL Any suggestions on what I can do? I am going to eventually replace all of the flooring in the house, but I can't afford to do upstairs right now. So I just have to make do. Thanks again in advance. Jen in Schertz.