Sec. 470.305. - Septic tank system construction standards.

Every septic tank system installed subject to this Chapter shall meet the following construction standards: (a) The septic tank shall be rectangular in shape with an inside length between two and three times the inside width. (b) The septic tank shall be watertight and free of voids or pits, shall have reasonably straight, plumbed wall, and shall be constructed from: (1) Concrete, either precast with adequate steel reinforcing to facilitate handling, or poured in place, designed by mix and water-cement ratio for a unit compressive strength of 3,000 per square inch after 28 days of curing. (2) With the approval of the Director, concrete block with a concrete bottom, plastered inside with cement mortar and with walls at least eight inches thick. (3) With the approval of the Director, other materials having substantially the same construction characteristics, taking into consideration the intended use of the septic tank. (c) The septic tank shall have the following minimum wall and bottom thickness: (1) If made from precast concrete: (i) Two inches, if the septic tank has a capacity of 1200 gallons or less. (ii) Three inches, if the septic tank has a capacity of more than 1200 gallons. (2) If made of concrete poured in place, four inches. (d) The septic tank top shall be reinforced with three-eighths-inch reinforcing steel rods on six-inch centers in each direction. A one-piece top shall have a 22-inch manhole over the inlet and outlet of the septic tank. A precast top in sections shall have the end sections over the inlet and outlet approximately 24 inches in width. The tank shall have a concrete top with a minimum thickness of: (1) If the tank has a capacity of 1200 gallons or less: (i) Three inches, if precast. (ii) Four inches if poured in place. (2) If the tank has a capacity of more than 1200 gallons, four inches. (e) The inlet and outlet shall be at opposite ends of the septic tank and shall be provided with tees extending five inches above and 18 inches below the liquid level line. The Director shall approve baffles in lieu of tees. The invert of the inlet and outlet shall be at the same elevation. (f) The effective depth of the septic tank shall be at least four feet and not more than five feet. (g) Ventilation shall be provided to the septic tank through building plumbing vents. (h) The septic tank shall have a minimum freeboard of eight inches if the tank has an effective capacity of 1200 gallons or less, and 12 inches if larger. (i) The bottom of a concrete septic tank shall be monolithic and an integral part of the walls, without any joint or seam. (Ord. 70-650-526; Ord. 71-397-181; Ord. 83-591-400, § 1) Note— Former § 624.305.