Look at all those roof lines. Even though they have gutters there may be to much water for them to handle. Combined that with the foundation drains not working and the water could be wicking up through the connection where the footing meets the wall. Just a guess though.
Common issue, the key point is that the house was never occupied.
Had it been sold, the builder would have been doing warranty work on that issue assuming he was still around and capable.
We have a huge amount of newer construction around here, its common to have major issues that show up the first few years. Most of it is quietly fixed by the builder as soon as the owner realizes they have a problem.
I have seen this before many times on new construction.
I agree with Peter, the lot is flat, with the steep roof heavy rain would probably overshoot the gutters. Too much for the drain tiles to handle and back up. Were there ruts in the soil or ground sinking along the base?
Architects and simple building science are sometimes strangers to each other.
I was about to say…
Peter beat me to it.
Way too much roof for the gutter system.
I have even had gutters dump into the foundation drain system. That worked out real well!
There is no one definitive cause for this problem. I listed all the possible causes and deferred for further evaluation with a structural engineer.
If sand was used for back fill and no sock placed on drain tile you will most likely find that drain tile wont drain. Send in a inspection camera and I’ll bet you find some kind of defect with it. Also some concrete contractors ether remove or punch many holes into the plastic when pouring the floor because they believe it finishes easier
There are two types of basements … those that are wet, and those that will be wet … 
Is that your professional opinion as an Engineer?
Dumb it down for us will you.
Seriously ,how about explaining the procedure to determine the cause for us as it would be helpful.
Yes it is … :mrgreen:
Below grade residential foundation construction is just not intended to be water tight … never has, and probably never will be. I have worked on many industrial projects that had building levels below groundwater and needed to be relatively dry. It requires very special designs, materials, and construction procedures that are very expensive. Even for residential foundations with high groundwater those special measures are not typically utilized.
There are many causes for wet basements, and to accurately determine the cause you really need to be on site and have a good amount of field experience evaluating and dealing with similar circumstances.
Fortunately home inspectors are only responsible for identifying an issue or problem, and are not responsible for determining the cause or how to perform the repair. However when you see a wet or moist basement you do need to think about possible causes, because there might be other defects that can lead to wet basements.
The book “Principles of Home Inspection” by Carson Dunlop has some good discussions on wet basements and water penetration issues, but I will say this. Since residential basements are not intended to be water tight, it is very important to keep water away from foundations. Studies have shown that a vast majority of basement moisture problems are related to poor roof drainage and site grading.
The concept is to collect water and discharge it where it will run off away from the foundations fairly quickly. Even a simple thing like clogged gutters from overhanging trees can lead to basement water penetration … particularly with poor grading (less than 6" drop in 10 feet, or a slope of about 1/2" per foot), porous surface materials (e.g. gravel or planting beds), or poorly constructed window wells (i.e. there should be 6" of gravel with the surface about 4"-6" below the sill, and covers). So look carefully at site grading and drainage issues first, and then start looking elsewhere.
Here is a link to a pretty good article on site grading and drainage related to basement water penetration issues. I don’t necessarily agree with everything, but it’s one of the better articles on the topic that isn’t written by a basement waterproofing company trying to sell you stuff … http://www.nrc-cnrc.gc.ca/eng/ibp/irc/ctus/ctus-n69.html … and here is another pretty good link … Stormwater Management - GreenBuildingAdvisor
Also check out the NACHI “Moisture Intrusion Inspection Course” … How to Inspect for Moisture Intrusion Course - InterNACHI® … which is free for members.
JMO & 2-Nickels … 
Thanks Robert.