I was having a real problem in my crawl space with water intrusion. I had installed two sump pumps, and a french drain to try and solve this issue with some success.  I was able to control the water but i really wanted to stop the water from coming in altogether.

I waited for a real heavy rain and went down to the crawl space to map out where the water was coming in from. What i found was several hole and cracks in the foundation where water was pouring through.

What i did next seems to have fixed the issue at least for now. I mixed up a batch of hydraulic cement to a thin state and painted it on the inside of my crawl space foundation. By the time i got to the end of the wall the other end was dry so i re-coated it three times.  This gave me almost a 1/2 inch of hydraulic cement over the entire wall.

This seems to have resolved the problem. I will have to at some time in the future dig up in front of the foundation and apply a water barrier there but for now hydraulic cement has been a life saver. It has given me the time to fix the bigger issue.