Illinois Administrative Code
Title 35 - ENVIRONMENTAL PROTECTION
Part 654 - RAW AND FINISHED WATER QUALITY AND QUANTITY
Subpart A - RAW WATER QUALITY
Section 654.101 - Surface Water Quality
Current through Register Vol. 48, No. 38, September 20, 2024
Surface water shall be approved as a community water supply source only if treatment to produce a finished water which meets the standards of 35 Ill. Adm. Code 604 is provided.
a) Sampling shall be performed to determine treatment requirements. Representative samples shall be collected at least once a month over 12 consecutive periods to determine raw water quality.
b) More frequent sampling shall be required to obtain a true representation of raw surface water quality. Raw water characterisitics shall be determined after heavy rainfall and runoff, low stream flow and at other times when unusual factors pertaining to physical and chemical quality, treatability, tastes, and odors exist.
c) A 12 month running geometeric mean shall be used to calculate raw water bacteriological quality.
d) Complete treatment including coagulation, clarification, rapid sand filtration or its equivalent, and continuous post-chlorination shall be provided for all surface waters.
e) Auxiliary treatment shall be provided for waters containing coliform bacteria exceeding 5,000 per 100 milliters in more than 20% of the samples examined during any one month. Examples of auxiliary treatment are presedimentation, prechlorination and storage of raw water for 30 days or more.
