BasementSoil

“Well drained” soil: The classification most American houses sit on

Water is removed readily but not rapidly. The profile is wet for only short periods after rain.

What it means for a basement

Well drained soil does not mean a dry basement. It means the ground is not the primary cause. In these counties the cause is nearly always the house: a failed footing drain, downspouts discharging at the wall, negative grade, or a window well with no drain.

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 “well drained” is the dominant class

2492 counties in our coverage, highest-risk 60 shown.

Page data updated