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02 March 2020 AdvancedGeo Project No. 20-5001 An Employer-Owned Company Page 7 of 14 5.2. SOIL LITHOLOGY AS RELATED TO FUTURE ONSITE SEPTIC USES The soil was visually described in accordance with the Unified Soil Classification System by a representative of AGE under the supervision of a California Professional Geologist. The soil collected from the percolation test hole boring consisted of dry clay from surface grade to approximately 30 inches bsg and sandy clay from 30 inches to 42 inches bsg. The soil type at the base of the borehole is considered semi-permeable and should be sufficient for liquid waste disposal and treatment. 6.0. PERCOLATION TEST INFORMATION A percolation soil suitability test was performed at the site under EHD permit No. SR0081699 using a four-inch diameter soil boring established to a depth of 42 inches bsg. A site map showing the approximate location of the percolation test hole is illustrated in Figure 2. A precise description of the location and construction of the percolation test hole is included in Appendix C (EHD form 42-03 revised 11/02/2009). The soil suitability study was conducted within the area of the proposed septic system leach field. 6.1. NUMBER OF PERCOLATION TESTS PERFORMED One shallow percolation test was performed at the site. The appropriate percolation test procedure established by the EHD was followed for the test (Procedure #2). The percolation test hole was pre-soaked overnight for 24-hour followed by a one-hour percolation testing period. 6.2. CONSTRUCTION OF PERCOLATION TEST HOLE On 06 February 2020, one boring was advanced for a shallow percolation test. The boring was advanced using a four-inch diameter hand auger to a depth of 42 inches bsg. The boring was located within the area of the proposed septic system disposal field. Following borehole advancement, the sides of the boring were scraped, and loose material was removed from the borehole. Once the borehole was cleared of loose material, two inches of fine gravel was added to the borehole. The borehole was then filled with water to a depth of 12 inches above the sand at the time of 0848. The test hole was then covered for 24 hours to allow for complete saturation of the borehole. 6.3. DESCRIPTION OF THE PERCOLATION TEST HOLE - POST SOAK On 07 February 2020, the boring was found to be completely dry, intact and in good condition.