The majority of water problems in crawlspaces/basements can be traced to faulty exterior grading or gutttering.

Next time it rains hard, don your raincoat and walk around the house looking for places where the water might be spilling over the gutters:

– Are the gutters working? Or does water overflow over the edges of the gutters?

– Where does the downspout of your gutters point the water? Is there a splash guard and/or piping to move the water away from the foundation?

– Is the grading OUTSIDE your foundation correct? I.e. it should slope away from the house. And it should be clayey, hardpacked soil, not sandy or other porous soil.

– Is the soil touching above where the foundation meets the beginning of the first floor? If so, water may be entering through this juncture.

Before you spend a bunch of money on french drains, also check out the following:

– Does the foundation extend into the water table? If so, there may not be many good options other than a french drain, sump pump, or similar system to move the water away.

– Did the builder happen to forget to put the plastic lining between the foundation’s exterior and the dirt? This is a building code requirement in NC, though perhaps it isn’t where you are located. Also if the dirt outside extends very far above where the plastic ends, you can get moisture problems.