What's Included on the Hydric Soils Lists

National List

“Hydric Soils of the United States” includes at least one phase in the listing that meets the hydric soil criteria. The list includes soil map unit components that are classified at categories higher than the series level in Soil Taxonomy (Soil Survey Staff, 1999).  It includes map units that may contain these components. This list includes both major and minor (small) percentages for map units. This means that in some cases most of the map unit may not be hydric. The list is useful in identifying map units that may contain hydric soils.  The National List is generated once per calendar year (usually in January or February) to satisfy legislated mandates.

The Natural Resources Conservation Service (NRCS) Hydric Soils Lists, available here, are by soil map unit component. Detailed and up-to-date hydric soil lists (e.g. by soil survey area map unit component) are maintained by the NRCS State Offices and local field offices.

State Lists

The state lists are subsets of the national hydric soils list. For more detailed state lists by mapunit, contact the appropriate NRCS State Office.

County Lists

NRCS has developed local lists of map units that contain hydric soils for each county or parish in the United States. These local lists are available at the NRCS State Offices (and usually available at local field offices) and are the preferred lists for use in making preliminary wetland determinations.