SR0080907 - Laserfiche WebLink

Home Browse Search

Percolation Test Results The completed percolation test form is included in Appendix 3 of this report. The form was signed by Ms. Afonskaia and indicates a percolation rate for the hole based on the final water drop observed. Per San Joaquin County Environmental Health Department's definition, a shallow percolation test hole has a depth between 36 and 42 inches; a satisfactory percolation rate for a shallow test is greater than or equal to 1 minute per inch (min/in) but less than or equal to 60 min/in drop. For the Site to utilize a standard septic system, one percolation test must demonstrate a satisfactory percolation rate within the proposed septic system disposal field. Details and results of the percolation test are summarized in the following table. Table 2. Percolation Test Summary Test No., Percolation Test Percolation Rate Test Duration Comments Date Tested Depth (ft.) (minutes/inch) (see notes) P1, 6/21/2019 3.03 9.26 4 hr. Satisfactor�r perc. rate Shallow Test Note: A satisfactory percolation rate for a "shallow" test is greater than 1 but less than or equal to 60 minutes per inch. 1 Per San Joaquin County Environmental Health Department, a rate between 5.0 and 30.0 min/in requires an eight-foot separation between the bottom of dispersal system and ground water, or mitigation by system design or enhancement. Discussion of Percolation Test Results The soils within the proposed sewage disposal area of the Site have demonstrated a satisfactory percolation rate for the use of a standard septic system in accordance with the requirements of the San Joaquin County Environmental Health Department. Because of the percolation rate between 5.0 and 30.0 min/in encountered in the test hole, the San Joaquin County Environmental Health Department will require an eight- foot separation from the bottom of the dispersal system to ground water (see Table 2). Ground water is anticipated to be encountered approximately 93 to 108 feet below ground surface at the Site; consequently, no modifications to standard septic systems should be required. Discussion of Septic System Sizing Septic system construction should follow the San Joaquin County On-Site Wastewater Treatment Systems Standards (2017) where applicable; additional recommendations related to nitrate mitigation will be discussed in the following pages. LOGE 1930 Page 7