Section 370.300  General Considerations

a)         Type of Sewers

The Agency will approve plans for new sewer systems and extensions only when designed as the separate sanitary type in which precipitation runoff and ground water from foundation drains are excluded.  The Agency will not approve the installation of new combined sewers, except as provided in 35 Ill. Adm. Code 306.302.

b)         Design Period

Sewer systems should be designed for the estimated ultimate tributary population, except in considering parts of the systems that can be readily increased in capacity.  Similarly, consideration should be given to the maximum anticipated capacity of institutions, industrial parks, etc.

c)         Design Factors

In determining the required capacities of sanitary sewers, the following factors should be considered:

1)         Design peak flow.

2)         Additional design peak flow from industrial plants.

3)         Ground water infiltration.

4)         Topography of area.

5)         Location of waste treatment plant.

6)         Depth of excavation.

7)         Pumping requirements.

(Source:  Amended at 21 Ill. Reg. 12444, effective August 28, 1997)