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Effective April 28, 2015 Chapter Four Subsurface Sewage Treatment System Regulations vary by more than ten percent. In other soils, the water depth must be adjusted to eight inches over the soil at the bottom of the test hole. From a fixed reference point, the drop in water level must be measured in inches to the nearest 1/16 inch at approximately 30-minute intervals and refilled between measurements to maintain an eight inch starting head. If water seeps away in less than 30 minutes, a shorter time interval between measurements must be used, but water depth must not exceed eight inches. The test must continue until three consecutive percolation rate measurements do not vary by more than ten percent. The percolation rate is also allowed to be determined by observing the time it takes the water level to drop one inch from an eight -inch reference point if a constant water depth of at least eight inches has been maintained for at least four hours prior to the measurement; (G) The time interval must be divided in minutes by the drop in water level in inches to obtain the percolation rate in minutes per inch. The percolation rates that are within the ten percent provision determined for each test hole must be averaged to determine the final percolation rate for that hole. The slowest final percolation rate for all holes within the soil dispersal area must be used for design; and (H) A percolation test must not be run where frost exists within 12 inches of the bottom of the percolation test hole. 9.8 Phase I; Site Evaluation Reporting. A written report on the site evaluation must be prepared and include the following: (1) Preliminary and field evaluation results from Sections 9.2 through 9.7 (2) Dates of preliminary and field evaluations. (3) Design calculations using the most current version of the design forms furnished by the University of Minnesota. (4) A map drawn to scale or dimension, with a north arrow, and including: (A) horizontal and vertical reference points of the proposed soil treatment and dispersal areas, soil observations, percolation tests, and pertinent distance from the proposed SSTS to all required setbacks, lot improvements, easements, ordinary high water mark of public waters, property lines, and direction and percent slope. (B) the location of any unsuitable, disturbed, or compacted areas. (C) the access route for system maintenance. (5) The estimated depth of periodically saturated soil layer, bedrock, or flood elevation, if appropriate. (6) The proposed elevation of the bottom of the soil treatment and dispersal system. (7) Anticipated construction related issues. (8) The name, address, telephone number, and certified statement of the individual conducting the site evaluation. (9) An assessment of how known or reasonably foreseeable land use changes are expected to affect system performance, including, but not limited to, changes in drainage patterns, increased impervious surfaces, and proximity of new water supply wells. (10) A narrative explaining any difficulties encountered during the site evaluation, including, but not limited to, identifying and interpreting soil and landform features and how the difficulties were resolved. (11) A notation of any differences between observed soil characteristics and those identified in the soil survey report. 9.9 Soil testing required. Applicants for subsurface sewage treatment system permits, site approvals or subdivision approvals will be required to submit soil test data from soil borings and percolation tests, or soil pits, for each proposed site or installation. The minimum testing shall be that necessary to verify suitable conditions for two complete soil dispersal and treatment areas. 37 Washington County Development Code