Drilling into cinder block foundation
Drilling weep holes in your foundation can create additional problems. 

Water problems around the foundation can be caused by: 1) High watertable, or 2) surface water runoff. 

1) If you have a high watertable, a perimeter drain is a must. (Depending on the size of the house, we may run a few drainlines under the house too.) If water is in the crawl space and the drainpipes are not deep enough to collect the water, then weep holes through the foundation wall MIGHT be appropriate. 

2) If water is collecting around the perimeter of the foundation, weep holes are NOT recommended, because water will run into the crawl space. 

Btw, cinder blocks have voids and can fill with water. Weep holes will allow the water to drain out, but should be installed through the outer shell (face) only. Installing a hole through the inner shell will allow the water in the cells to drain into the crawl space.