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12958/12970 E lahant Road Project No. 2022-00037 P a g e 111 <br />A visual inspection of the soil from on-site auguring indicates a low potential for percolation in clay <br />observed down to 100 inches, and a high potential for percolation in the sandy loam observed from <br />140 to 147 inches. A percolation test is the best method to determine the suitability of the soils for a <br />septic disposal area. Please see the next section for percolation test results. Generally speaking, <br />coarser -grained soils have much greater potential for percolation than fine-grained or cemented <br />soils. <br />8.2 Percolation Test Procedure <br />Two percolation tests were conducted for the soil borings on June 15, 2022 in accordance with the <br />requirements of the EHD. A 4 -hour percolation test was performed for the shallow percolation test <br />due to the slow percolation rate observed, and a 1 -hour percolation test was performed for the deep <br />percolation test due to the first 6 inches of water seeping away in less than 30 minutes after the <br />overnight saturation period. The last half hour of the test 4 -hour test and the last 10 -minutes of the <br />1 -hour test was observed by Francisco Ruiz, Registered Environmental Health Specialist, EHD. <br />Measurement of the water level during the percolation test was from a fixed reference point on the <br />PVC casing using an electric well sounder with a depth accuracy of 1/100th foot. All tabulated values <br />on the field data sheet are in decimal feet. After water drop was observed, the hole was checked for <br />refill. The refill level was approximately 0.5 ft (6 inches) of water above the bottom level of the <br />percolation test holes. The readings were taken every 30 minutes for a period of four (4) hours for <br />the shallow percolation test and every 10 minutes for a period of one (1) hour for the deep <br />percolation test. <br />8.3 Percolation Test Form and Results <br />The completed percolation test permit and test form are included in the Appendix E of this report. <br />A shallow percolation test is defined by the EHD as being between 36 and 42 inches in depth and a <br />deep percolation test is defined as 42 inches to 25 feet, with a minimum of 10 feet above the water <br />table; a satisfactory percolation rate for a test is less than or equal to 60 minutes per inch drop and <br />greater or equal than 1 -minute per inch drop. The percolation test must demonstrate a satisfactory <br />percolation rate within the proposed septic system disposal field of each parcel to utilize a standard <br />septic system. Details of the percolation test is summarized in the table below. <br />Table 6. <br />Summary of Percolation Test - November 1, 2019 <br />Test No., <br />Percolation <br />percolation Rate <br />Test <br />Comments <br />Date Tested <br />Test <br />(minutes/inch) <br />Duration <br />(see notes) <br />Depth (feet) <br />21300 Mann Road <br />P-1 (shallow) <br />3.25 <br />250 <br />4 hours <br />Unsatisfactory <br />P-2 (deep) <br />12.25 <br />1.81 <br />1 -hour <br />Satisfactory <br />Note: A satisfactory percolation rate for a "shallow" test is less than or equal to 60 minutes per inch and greater than or equal to 1 <br />minute per inch. <br />Petralogix Engineering, Inc <br />26675 Bruella Road, Galt Ca 95632 <br />(209)-400-5729 <br />www.petralogix.com <br />