35 Ill. Adm. Code 604.1340
Elevated Storage
Section 604.1340Â Elevated Storage
a)Â Â Â Â Â Â Â Â The
minimum storage capacity must:
1)Â Â Â Â Â Â Â Â be
equal to the average daily usage or be based on an engineering study of the
distribution system hydraulic conditions, anticipated domestic water demands of
the system, and, where fire protection is provided, fire flow demands; and
2)Â Â Â Â Â Â Â Â be
capable of maintaining adequate pressures as described in Section 604.1415(a).
b)Â Â Â Â Â Â Â Â Elevated
tanks with riser pipes over eight inches in diameter must have protective bars
over the riser openings inside the tank.