Block-Like Soil Structure with peds greater than 2.5 cm (1 inch) in size within 36 inches of the naturally occurring soil surface shall be considered __________________ as to structure.

• A. Unsuitable
• B. Provisionally suitable
• C. Suitable
• D. Unclassified

Answer: (A)

Soil structure near the surface controls how well water can move through the profile, which is crucial for septic drainfield performance. When you have a block-like structure with peds larger than 2.5 cm (about 1 inch) within 36 inches of the natural surface, the pore spaces are large and discontinuous, and the soil tends to drain unevenly. This creates poor and inconsistent infiltration, increases the risk of perched water or surface pooling, and can lead to instability in trench bottoms. These limitations are significant enough that the soil would be considered unsuitable for supporting adequate septic drainage from a structural standpoint. The other classifications would imply that the limitation is manageable or not as critical, but the presence of large near-surface peds represents a fundamental, unresolved constraint, so it is deemed unsuitable.