We moved into the home we are living in 3 years ago. It was built in 2008. We have a finished basement that had wall to wall carpeting throughout the whole basement except for the bathroom, laundry room and furnace room. The laundry room and bathroom are tiled. The furnace room is all concrete. We noticed some staining on the carpet in some random areas when we moved in( previous owners had kids so we figured they were spills). However, as time went on the stains seemed a little darker and maybe a bit bigger in some of these spots( most of which are in the middle  of the rooms in random spots. Like maybe 6 small areas all together than we saw had stains on the carpet). We used a moisture meter to check these spots and some of them showed elevated levels of moisture. We had a environmentalist come out and he checked everything over and said everything looked good, no indications of water damage or mold. He did suggest we rip the rug out saying basements ( even finished ones should not really have carpeting. He said ours was old anyhow and better to just take out since I have allergies anyways). Well we ripped out all the carpeting little over a week ago. We rechecked the areas that showed moisture before now that the carpet was out and they registered pretty much like the rest of the floor, it was not elevated like when the carpet was in.  We even had a waterproofing company come out to inspect and see if we needed to seal the concrete floor. He said everything looked very good, that he saw No visible cracks or anything and just suggested a dehumidifier since the basement can get humid. Well last night we had very heavy rains and this morning we noticed in one of the bedrooms right in the middle of the floor basically where we had a small throw rug( the size of a rug you would put in front of your kitchen sink) and it was very wet( the whole rug was wet). However, everything else around this area and around the walls were dry. The dry wall does not touch the ground   thank God so that was done right. But there is no evidence of water intrusion anywhere near the walls. This was in the middle of the room. It did not come from above either. We threw the little area rug out and now the concrete is dry, there is no water standing there anymore.  It seems like the rain caused some kind of seepage to get in. I am wondering if it is hydraulic pressure from the heavy rain that caused water to seep up in that spot? I am not sure. Just wanted to hear your thoughts. We were going to put a different flooring in ( tile or maybe Marmoelum click tiles), but now need to figure this out first. What could be possibly be causing this, and who would I contact to figure this out? I live in Chicago IL. 

Thank you.

Jennifer