Rock, grade and changing soil shape the drainage plan
In Leander, shallow limestone and sloping ground often leave stormwater little time to soak in. During a heavy rain, water runs over the surface, follows rock layers or compacted fill, and settles in the low spots it reaches first. That can leave water collecting near a patio, along a side yard, or against the foundation.
Clay-bearing pockets add a changing pattern to that runoff. Once saturated, they shed water; after a long dry stretch, they shrink and open up. The route water takes through a yard can therefore change with the weather, so the visible wet area is only part of what needs attention.
A drainage route needs to follow the actual grade and a practical outlet for that property. Rock close to the surface affects where a trench can run and how deep it can be, while fast-moving runoff affects where an inlet belongs and how it is kept clear of sediment. Moving water away from the structure also requires a discharge point that does not send it back across the yard, wear away its route, or concentrate runoff beside buried utilities.