Often, people call and inquire why the block under their garage wall is leaking even though the block is 100% above grade.  Inevitably, the problem is that the block is not, and has never been sealed.  Block is very porous and acts like a sponge.  This is evident if you place a dry block in about 1” of water and wait twenty-four hours.  Depending on the air humidity, it may be 100% saturated.  Similarly, if water is allowed to sit against the block or during an extended rain event with water coming off the roof and splashing, the block will saturate and leach to the dry side which is in the building.  Block should be sealed with house paint or a good sealer on the weather side only allowing it to dry to the inside.