To obtain reproducible results with a soil percolation test, it is very important to:

Soaking the hole with water before conducting a soil percolation test is critical for obtaining reproducible results. This practice ensures that the test pit is saturated, allowing for accurate measurement of the soil's percolation rate. Saturation eliminates variability from atmospheric moisture and helps provide consistent conditions in which to measure how quickly water moves through the soil. Proper saturation also helps to prevent issues such as clogging or soil compaction, which may arise if the soil has not been adequately soaked.

In contrast, adding gravel to the bottom of the test pit might not directly contribute to the reliability of the results; it could potentially alter the percolation characteristics being measured. Cross-referencing with soil maps is useful for understanding soil types and their typical drainage characteristics, but it does not influence the mechanical testing process itself. While repeating the test or using dual pits can help verify results, proper preparation of the test site through soaking the hole is fundamental for ensuring an accurate initial measurement of percolation rates.