The Ontario Building Code | General Requirements
18.104.22.168. General Requirements
(1) A leaching bed shall not be located,
(a) in an area that has an average slope that exceeds one unit vertically to four units horizontally,
(b) in soil orleaching bed fill having a percolation time of,
(i) less than one minute, or greater than 125 minutes if constructedas a shallow buried trench, or
(ii) less than one minute, or greater than 50 minutes for all other leaching beds, or
(c) in or on an area that is subject to flooding that may be expected to cause damage to the leaching bed or impair the operation of the leaching bed.
(2) A leaching bed shall not be covered with any material having a hydraulic conductivity less than 0.01 m/day.
(3) The surface of the leaching bed shall be shaped to shed water and together with the side slopes of any raised portion, shall be protected against erosion in such a manner as to not inhibit the evaporation and transpiration of waters from the soilor leaching bed fill, and to not cause plugging of the distribution pipe.
(4) No part of a leaching bed shall be sloped steeper than 1 unit vertically to 4 units horizontally.
(a) the impairment or destruction of any pipe in the leaching bed, or
(b) the smearing of the soil or leaching bed fill.