(A) General. In any district where an individual private sewage system is used in place of public facilities, the minimum size lot area, width and depth shall be subject to the approval of the Building and Zoning Committe of the County Board but shall not be less than 40,000 square feet. When doubt exists with the Building and Zoning Committee as to the adequacy of the soil structure of the lot to properly accommodate an individual sewage system, the Committee may require the property owner to obtain a written opinion as to the size of lot required for an individual sewage system to operate on the lot according to safe health standards and further provide that the lot size shall not endanger or compromise reasonable and similar use of adjacent properties. If the findings of the soils scientist or engineer indicate that larger lots are necessary, the Committee may require lot size in excess of the minimum area defined previously in this division.
(B) Design. The design of an individual sewage disposal system shall take into consideration location with respect to wells or other sources of water supply topography, existing individual sewage disposal systems on adjacent properties, water table, soil characteristics, available area, expected volume of domestic sewage, and shall comply with all applicable county regulations as well as those of the Illinois Department of Public Health. The Committee may prohibit installation of sewage disposal facilities requiring a soil absorption system where such systems will not function due to high ground water, flooding or unsuitable soil characteristics.
(C) Design standards. The following design standards shall also apply:
(1) No part of any drain field shall be within 100 feet of any well, lake, stream or other body of water.
(2) No septic tank shall be smaller in size than 1,000-gallons’ liquid capacity. For mobile homes a 750-gallon septic tank will be permitted.
(3) Drain fields shall not be allowed in areas over 12% slope.
(4) Drain fields shall not be constructed in areas where the ground water table (permanent, fluctuating or seasonal) may be less than four feet below the bottom of the trench or bed.
(5) Septic tanks and subsurface seepage fields or buried sand filters shall not be constructed in an area where there is less than 30 feet of soil between the lowest point in the seepage system and the top of a limestone formation.
(6) Private sewage plats for subdivisions: Sewage plat shall be required for all new subdivisions of five lots or greater that are not on sewers. Such plat shall be prepared and submitted by a licensed engineer under the engineers seal. Each plat shall include: Soil borings will be used and locations noted on private sewage plat to determine subdivision lot suitability for subsurface seepage systems. The number of borings required should be sufficient in number to satisfy the engineer that subsurface seepage type systems shall work on all lots. Each private sewage plat will identify a location on each lot that will support a subsurface private sewage system. The type of private sewage system must also be identified on the private sewage plat. In the event a lot is found incapable of supporting a subsurface private sewage system and an above ground discharge type system is proposed, a determination under the engineers seal must be included that indicates the location of the proposed discharge and that the operation or use of the above ground discharge system will not create pooling or a nuisance on adjoining lot(s). A statement shall be included on the applicability of NPDES permits for the above ground discharge of any private sewage system proposed.
(Ord. 2014-18, passed 4-16-2014; Ord. 2020-02, passed 1-16-2020; Ord. 2024-01, passed 3-5-2024)