Concrete flat work poured against foundation walls may cause leaking
If you have groundwater entry below grade, into your crawlspace or basement, and you have concrete flat work that is poured against the foundation, with a flat or negative slope that runs rainwater turned into groundwater to the foundation, you may need to demolish the slab for at least 3 feet from the foundation after making a clean concrete saw cut.
Replace the area with a compacted splash block of dirt or clay for about 2 feet from the foundation, and install a 12″ wide hand excavated french drain with a slope of at least 2″ per 10 lineal feet, to solve your groundwater problem.
This may be your only option, unless the source of the groundwater is an overflowing rain drain discharge, or an overflowing gutter.
If the groundwater problem is actually caused by rainwater that slopes towards the foundation, the air space that is created between the foundation and the slab because they were poured at different times, will cause the rainwater to run right down the foundation wall to the basement, or under the foundation footing.
The solution is to compact a splash block preventing groundwater that hits the side of the home from standing on the foundation.
To prevent this, install a hand excavated french drain approximately 12″ wide at the base of the compacted splash block. Cover the splash block with river rock, as is contained in the hand excavated french drain, to prevent splash block erosion. Leave the river rock in the hand excavated french drain exposed on the surface. If you can, raise the grade at the foundation for the hand compacted splash block about 8-10 inches.