35 Ill. Adm. Code 305.103
Effluent Measurement
Section 305
Section 305.103 Effluent
Measurement
To enable the Agency to inspect
and investigate under Section 4(d) of the Act, all effluent discharge sewers,
pipes or outfalls must be designed or modified so that a sample of the effluent
can be obtained at a point after the final treatment process and before
discharge to or mixing with any waters of the State. All treatment works must
include devices for taking samples and for measuring and recording effluent
flow as the Agency may reasonably require.