Percolation Test (Perc Test) The Perc Test is a relatively complex procedure designed to determine how rapidly effluent will enter the soil on your lot during the wettest, worst-case condi-tions. All characteristics used while deter-mining loading rates are collected by a soil scientist. This information can help you correlate perc rates that may be more familiar to you with soils information. Soil horizons of stronger consistence than very firm consistence are not acceptable. The cost factor ranges from 2.5x to 3.5x. percolation. The cost factor ranges from 2.0x to 2.5x. All characteristics used while deter-mining loading rates are collected by a soil scientist. The soil’s percolation condition at a specific parcel of land is determined by testing at the site. A rate of 60 minutes per inch (MPI), meaning the water dropped one inch in 60 minutes, is often the cutoff point for a standard gravity-flow septic system, although the maximum number varies from 30 to 120 MPI depending on local regulations. The percolation rate is usually expressed in minutes per inch of drop. Also, the table should not be used for soil horizons with smectitic mineralogy. This could result in groundwater contamination, especially if the water table is shallow. If the underlain soil layers are different from upper soil layers, the steady state infiltration rate may vary significantly from the percolation rate. Determine site suitability – If the percolation rate for the site is faster than 5 mpi, the soil is unsuitable for a drain field system. infiltration. This could result in groundwater contamination, especially if the water table is shallow. Sandy soil is quite loose, so the percolation rate of water is highest in sandy soil but lowest in the clay soil because it is very compact. The table is used only for soil horizons of very firm or weaker consistence. Waste water would travel too quickly through the soil to be treated properly. Percolation. percolation. D. Soil restrictions. is the movement of water INTO the soil surface. Approximate percolation rates of each horizon can be correlated to loading rates. In Ohio, soil absorption systems can be used in areas where the percolation rate of the soil is between 3 and 60 minutes per inch (soil permeability between 1 and 20 inches per hour). controls the infiltration rate. In general, the lowest loading rate observed in the upper 30 to 42 inches of the soils examined is used for septic system design and sizing. Dig a test hole 6’ in depth or to rock or water, whichever occurs first. in soils. Percolation rate. A soil restriction is a feature in the soil that impedes the percolation of water. Determine site suitability – If the percolation rate for the site is faster than 5 mpi, the soil is unsuitable for a drain field system. is primarily due to gravity pulling the water vertically downward . Silty soils, including loam, have moderate percolation speeds, ranging from 0.1 to 1 inch per hour. is the movement of water WITHIN the soil matrix. Low Potential – These soils have one or more limitations, such as low percolation rate and depth to seasonal high water table, that require extensive design and site preparation to overcome. THE PERCOLATION RATES VARY MORE THAN 20 MPI, THEN THE PERCOLATION RATE IS NOT AVERAGED AND THE HIGHEST PERCOLATION RATE IS NOT AVERAGED AND THE HIGHEST PERCOLATION RATE IS USED TO DESIGN THE SYSTEM. The table is used only for soil horizons of very firm or weaker consistence. absorption areas are shown in Table 1. upper layers of soil where the infiltration rate is measured and lower layers where percolation occurs. Paddy (rice crops)is planted in standing water in the fields. difficult to calculate representative values of permeability from actual measurements Perc Rate . This is the "Goldilocks" situation, in which a soil holds water and nutrients long enough for plant roots to absorb them, but the soil does not easily become waterlogged. Rainwater percolates through the soil and collects above the bedrock. percolation rate, that are generally overcome using commonly applied designs. Percolation. infiltration. A soil percolation report uses water absorption rates for specific parcels of land to determine the appropriate onsite wastewater treatment systems (OWTS) that can be used for proposed development. NSSH Exhibit 618-9 Infiltration Rates: P bilit Ksat for general soil texture groups Soil Properties Permeability Texture Classes Rate In/Hr Rate um s-1 Low Rv High Low Rv High S, Gr Very rapid 20.00 60.0000 100.00 >141.00141 >141.00 LS FSLS, FS Rapid 6.0000 13.0000 20.0000 42.0000 91.5000 141.0000 LFS, FSL, SL Moderately rapid This level of groundwater is called water table. Also, the table should not be used for soil horizons with smectitic mineralogy. When the percolation rate for an individual hole is in excess of 240 minutes/inch, the area represented may be retested one time and the most favorable rate used to calculate the percolation rate. BORE HOLE . Soil horizons of stronger consistence than very firm consistence are not acceptable. At least 4 feet of suitable soil is required under the soil absorption system to provide … Waste water would travel too quickly through the soil to be treated properly. 1.