BLOCK-Like Soil Structure - Block-Like Soil Structure with peds 2.5 cm (1 inch) or less in size shall be considered _______________________________ as to structure.

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

Answer: (C)

When assessing soil structure for septic system suitability, the size and arrangement of peds tell you how water will move through the soil. Block-like structure with very small peds (2.5 cm or 1 inch or smaller) is considered provisionally suitable as to structure. The small blocky peds indicate the structure isn’t clearly ideal, but it isn’t clearly unacceptable either, so the soil can be accepted for the design in a provisional sense. This category signals that some caution and further checks are advisable—verify other factors like permeability, depth to groundwater, and any restrictive layers—to confirm it will perform as needed. Larger or more pronounced blocky structure would raise more concerns about infiltration and stability, making the site less likely to be suitable.