BasementSoil

“Somewhat excessively drained” soil: Free-draining ground with a little more water-holding capacity

Sandy loams and gravelly loams. Still fast, still low in clay.

What it means for a basement

Seepage is possible after extreme rain or snowmelt, but sustained hydrostatic pressure is unusual. Surface water management is normally enough.

Where the USDA definition comes from

Drainage class is assigned per soil component in the national soil survey and describes frequency and duration of wet periods under conditions similar to those under which the soil formed. It is not a measurement taken at your house; it is a classification of a mapped soil body. That distinction is why we phrase every county page as a statement about soil, never as a statement about your basement.

USDA NRCS, National Soil Survey Handbook, part 618. Delivered per map unit in SSURGO.

Counties where “somewhat excessively drained” is the dominant class

39 counties in our coverage.

Page data updated