Does the ground/landscape outside the wall where the leak is slope TOWARDS the house? Does the gutter, or gutters CLOSEST to the leak 'dump' their water at the wall? Assuming there isn't a gutter at the roofline above the leak, does water run off it when it rains? Should there be gutters up there? Do the gutters leak? Does any water 'pool/collect' near or at the wall where the leak is?
If the answer to ANY of these ?'s is yes, then you need to 'correct' it so it DOESN'T happen. The next time you get a decent rain storm, put on your boots and raincoat and grab an umbrella (assuming there's no lightening), and do a walk-around the house to see how water runs OFF the roof, into the gutters (if any), and out the downspout. THAT should help you.
I know of many-a-basement with hairline cracks that DON'T get any water in them. (The reasons vary but correcting the 'problems' I've described should alleviate or even eliminate the problem.)