35 Ill. Adm. Code 375.201
Policy
Section 375
Section 375.201 Policy
It is the intent of this policy
that water quality investigations be no more extensive than is necessary:
a) to identify the degree of CSO control appropriate for a
specific community as mutually agreed to by discharger and Agency, and
b) to substantiate the appropriateness of the proposed control
program under the scrutiny of the Board in a proceeding pursuant to 35 Ill.
Adm. Code 306: Subpart D.