A. Septic Tank Specification. All septic tanks shall conform to the specifications required in Section 905.40 of the Illinois Private Sewage Disposal Code.
B. Septic Tank Capacity. Septic tank capacity for residential property shall be sized in accordance with the provisions of Table III (See Appendix B). The minimum size septic tank for any installation shall be 1000 gallons. Septic tanks for any establishment other than residential property shall be sized in accordance with the estimated flow determined from data provided in Table II (See Appendix B). The size of the septic tank shall be calculated as follows:
1. The volume of the liquid level shall be one and one-half times the daily estimated flow.
2. When the total flow exceeds 1350 gallons per day, two or more tanks in series, or a multi-compartment tank, shall be installed.
C. Septic Tank in Series. Whenever two or more septic tanks are to be used, they must be installed in series. If two tanks are used, the capacity of the first tank shall be at least one-half but not more than two-thirds of the total liquid capacity as calculated from either Table II or Table III.
D. Garbage Grinders/Garbage Disposals. When garbage grinders/garbage disposals are used in residential property, solids shall be retained by one of the following methods:
1. Solids Retention Tank. A solids retention tank constructed in accordance with Section 905.40 of the Illinois Private Sewage Disposal Code shall be placed between the domestic sewage source and the septic tank to intercept solids from the garbage grinder. This tank shall receive waste from the garbage grinder(s) or the kitchen wastes only. No other fixtures shall discharge into this tank. The solids retention tank shall be at least 50% in liquid volume of the septic tank sized for the waste from the rest of the property, however, the minimum size tank to be used shall be 500 gallons.
2. Septic Tank Sized Per Table III. A septic tank receiving all flows from the property sized in accordance with Table III (See Appendix B).
E. Septic Tank Access. Access to the interior of the tank shall be provided to allow inspection and maintenance. A manhole or access port extension collar or riser with a minimum dimension (width or diameter) of 12 inches shall be provided by the private sewage disposal contractor to bring access to the tank to the ground surface. The joint between the septic tank and the riser(s) shall be watertight. When the riser consists of multiple sections, all joints shall be watertight. If a 2 compartment tank is used and the tank has an opening over the wall between the compartments, the center opening shall have access provided within 12 inches of the ground surface.
F. SEPTIC TANK INSTALLATION.
1. Level Tank. The septic tank shall be set level and backfilled to prevent floatation or drifting of the tank. Level shall mean plus or minus one-half (1/2) inch in any direction (length or width or diameter of the tank).
2. Watertight Openings. If the inlet, outlet or access openings are to be set at or below the seasonal high water table, all openings in the tank shall be made watertight using mastic, tar, silicone caulk, etc.
3. Connections in Overdig. There shall be no connections such as joints, splices, or fittings within the area of overdig around the septic tank.
(Ord. O-201711-51-031, passed 11-14-2017)