A hard, dry yard can send storm water running instead of soaking it in
In Merkel, dry and compacted ground can shed a heavy rain before it has time to absorb much of it. Short, hard storms leave water looking for the lowest route. It can gather in low spots, run toward the edge of a slab, or follow the disturbed ground beside utility trenches and earlier excavations.
That makes the visible puddle only part of the drainage question. We look at the existing slope, where roof water discharges, and the route water takes after rain. A drain placed only at the wettest spot does little if its line has nowhere dependable to send the water. The work needs a route that collects surface water and carries it away from the building without sending the problem across the yard.
Keeping water from repeatedly soaking the soil beside the foundation also matters after a dry spell. Soil that has dried out can swell once it is wet again, and repeated wetting contributes to uneven movement in the ground. A workable grade and a reliable drainage route help keep that water from staying where it does the most harm.