A. Minimum Improvements Required: No subdivision shall be laid out within the city or within one and one-half (11/2) miles of the corporate limits thereof without providing the following minimum improvements:
1. Street Grading And Specifications: Grading to their full width, including side slopes, and to the appropriate street grade, of all streets within the area being subdivided. Streets shall be constructed according to specifications of the Illinois department of transportation with a wearing surface of not less than two inches (2") of class I bituminous concrete surface course. The base shall be of aggregate, gradation CA-6, the depth of which shall be determined by soil tests in accordance with Illinois department of transportation standards but not less than eight inches (8") thick, compacted to not less than ninety eight percent (98%) of the standard laboratory density. In lieu of flexible pavement, a structurally equal concrete pavement constructed according to the specifications of the Illinois department of transportation may be used.
2. Street Paving; Curbs And Gutters: Permanent concrete or asphalt paving, at least twenty seven feet (27') in width, including combination concrete curb and gutter on each side, on all streets within the subdivided area where property is platted in lots which, on average, are less than twenty thousand (20,000) square feet in area and one hundred feet (100') in frontage width; and in all other cases, permanent concrete or asphalt paving, as specified in subsection A1 of this section, at least twenty feet (20') in width without curbs or gutters. Along such pavements of twenty feet (20'), usable shoulders with a slope of one-half inch (1/2") per foot and drainage ditches where appropriate with slopes of three feet (3') horizontal for each foot vertical and at least one foot (1') in depth shall be provided. Any combination concrete curb and gutter shall have a mountable curb, four inches (4") high and six inches (6") wide, with nine inch (9") wide gutter, one and one-half inches (11/2") high and twelve inches (12") wide.
3. Sidewalks: Concrete sidewalk on at least one side of each street at least four feet (4') in width and four inches (4") thick where property is platted in lots which, on average, are less than twenty thousand (20,000) square feet in area and one hundred feet (100') in width.
4. Sewer System:
a. Sanitary sewers and service to each lot where an existing public sewer is reasonably accessible.
b. Where an existing sewer is not reasonably accessible, individual sewage disposal devices may be used, provided all lots are twenty thousand (20,000) square feet or more in area, and the disposal devices are constructed in accordance with regulations and requirements of, and are specifically approved by, the Illinois department of public health, and Knox County, where applicable.
5. Water Supply:
a. Connections to a public water supply and service to each lot.
b. Where a public water supply is not reasonably accessible, wells or some other private water supply may be used, provided such source will supply adequate quantities of potable water and is approved as to construction and its relation to lot areas and the method of sewage disposal by the Illinois department of public health.
6. Surface Water Drainage: Adequate drainage of the property to prevent the accumulation of stormwater. The subdivider shall install catch basins, culverts, and laterals leading to an outfall into the main channel or trunk line drain for the basin of which the subdivision is a part. If no outfall exists, an estimate of the cost of the outfall shall be prepared by the engineer ordinarily retained by the city for the design or construction of public improvements therein or, if no engineer is ordinarily retained for such purpose, by an engineer registered in the state of Illinois mutually agreed upon by the city and the subdivider, and the subdivider shall make a onetime payment of the fair share of the costs of the outfall to be charged against the subdivision on the basis of percentage of acreage of the total basin. Cash, bond, or securities shall be deposited with the city treasurer into a special outfall improvement account for that drainage prior to approval of the final plat.
B. Review Of Improvements: Before final approval of any subdivision plat is granted by the city council, the proposed plans for and the methods of providing the improvements required in this section shall be reviewed and approved by the engineer described in subsection A6 of this section.
C. Installation And Costs: All improvements required in this section shall either be installed prior to submission of the final plat or, in lieu thereof, an estimate of the cost of all improvements shall be prepared by the engineer described in subsection A6 of this section, and a surety bond, cash, or escrow agreement shall be submitted along with the plat to guarantee construction of all such improvements. (2006 Code § 11-1-4)