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1. Agricultural drain tile shall be in 12-inch lengths and laid with 1/4-inch <br />open joints on grade boards. All open joints shall be protected on top by <br />strips of asphalt-treated building paper at least ten inches long and three <br />to six inches wide or by other acceptable approved means. <br />2. Perforated plastic pipe shall be laid with one row of perforations on the <br />bottom. Perforations shall be at least 1/2-inch in diameter and spaced no <br />farther than 12 inches apart. <br />3. Other devices may be used to distribute sews -ank effluent over the soil <br />treatment area upon approval of the local ai­,istrator of the sanitary <br />ordinance. <br />4. The distribution pipes shall be laid level or on a uniform slope away from <br />the sewage tank of no more than four inches per 100 feet. <br />F. The filter materials shall be covered with untreated building paper or a <br />two-inch layer of hay or straw or similar, approved permeable me-:erials. <br />G. The trenches or beds shall be backfilled with the excavated ma.. :aa and <br />slightly crowned above finished grade to allow for settling. oackfill <br />shall not be compacted to a density greater than that of the original scil. <br />H. The minimum depth of cover over the distribution pipes shall be at least <br />eight inches. <br />I. The maximum length of any drainfield trench shall be no more than 100 feet. <br />J. The maximum depth of cover over the distribution pipes shall be no more <br />than 36 inches and preferably 24 inches. <br />K. A grass cover shall be established over the soil treatment area. <br />L. Bottom of trenches shall be no more than "4 inches below existing ground. <br />Season,;l high water table was noted at a depth of 5.1 feet. <br />M. See Details for further details. <br />