For how long is percolation testing considered valid?

Percolation testing is considered valid for an indefinite period of time primarily because it assesses the soil's capacity to absorb and transmit water, a characteristic that does not change significantly over short periods. Once a percolation test is conducted and the results are recorded, those results provide a reliable indication of the soil's long-term drainage capability, as soil properties typically remain stable in the absence of significant environmental changes, such as substantial soil disturbance or modifications in land use.

Therefore, unless there are drastic environmental changes, the results of a percolation test can be utilized for future planning and design of septic systems or drainage solutions without needing to be repeated frequently. It's important for practitioners to recognize that this validity is contingent on the soil remaining undisturbed and unaltered in ways that would affect its percolation properties.