Ill. Admin. Code tit. 35, § 611.350 - General Requirements
"Action level" means that concentration of lead or copper in water computed under subsection (c) that determines, in some cases, the treatment requirements of this Subpart G that a supplier must complete. The action level for lead is 0.015 mg/l. The action level for copper is 1.3 mg/l.
"Corrosion inhibitor" means a substance capable of reducing the corrosivity of water toward metal plumbing materials, especially lead and copper, by forming a protective film on the interior surface of those materials.
"Effective corrosion inhibitor residual" means a concentration of inhibitor in the drinking water sufficient to form a passivating film on the interior walls of a pipe.
"Exceed", as this term is applied to either the lead or the copper action level, means that the 90th percentile level of the supplier's samples collected during a six-month monitoring period is greater than the action level for that contaminant.
"First draw sample" means a one-liter sample of tap water, collected in accordance with Section 611.356(b)(2), that has been standing in plumbing pipes for at least six hours and which is collected without flushing the tap.
"Large system" means a water system that regularly serves water to more than 50,000 persons.
"Lead service line" means a service line made of lead that connects the water main to the building inlet, including any lead pigtail, gooseneck, or other fitting that is connected to such lead line.
"Maximum permissible concentration" or "MPC" means that concentration of lead or copper for finished water entering the supplier's distribution system, designated by the Agency by a SEP that reflects the contaminant removal capability of the treatment properly operated and maintained.
BOARD NOTE: Derived from 40 CFR 141.83(b)(4). (See Section 611.353(b)(4)(B).)
"Medium-sized system" means a water system that regularly serves water to more than 3,300 up to 50,000 or fewer persons.
"Meet", as this term is applied to either the lead or the copper action level, means that the 90th percentile level of the supplier's samples collected during a six-month monitoring period is less than or equal to the action level for that contaminant.
"Method detection limit" or "MDL" is as defined at Section 611.646(a). The MDL for lead is 0.001 mg/l. The MDL for copper is 0.001 mg/l, or 0.020 mg/l by atomic absorption direct aspiration method.
BOARD NOTE: Derived from 40 CFR 141.89(a)(1)(iii).
"Monitoring period" means any of the six-month periods of time during which a supplier must complete a cycle of monitoring under this Subpart G.
BOARD NOTE: USEPA refers to these as "monitoring periods". The Board uses "six-month monitoring period" to avoid confusion with "compliance period", as used elsewhere in this Part and defined at Section 611.101.
"Multiple-family residence" means a building that is currently used as a multiple-family residence, but not one that is also a "single-family structure".
"90th percentile level" means that concentration of lead or copper contaminant exceeded by ten percent or fewer of all samples collected during a six-month monitoring period under Section 611.356 (i.e., that concentration of contaminant greater than or equal to the results obtained from 90 percent of the samples). The 90th percentile levels for copper and lead must be determined under subsection (c)(3).
BOARD NOTE: Derived from 40 CFR 141.80(c).
"Optimal corrosion control treatment" means the corrosion control treatment that minimizes the lead and copper concentrations at users' taps while ensuring that the treatment does not cause the water system to violate any national primary drinking water regulations.
"Practical quantitation limit" or "PQL" means the lowest concentration of a contaminant that a well-operated laboratory can reliably achieve within specified limits of precision and accuracy during routine laboratory operating conditions. The PQL for lead is 0.005 mg/l. The PQL for copper is 0.050 mg/l.
BOARD NOTE: Derived from 40 CFR 141.89(a)(1)(ii) and (a)(1)(iv).
"Service line sample" means a one-liter sample of water, collected in accordance with Section 611.356(b)(3), that has been standing for at least six hours in a service line.
"Single-family structure" means a building that was constructed as a single-family residence and which is currently used as either a residence or a place of business.
"Small system" means a water system that regularly serves water to 3,300 or fewer persons.
BOARD NOTE: Derived from 40 CFR 141.2.
Amended at 33 Ill. Reg. 633, effective December 30, 2008
BOARD NOTE: Derived from 40 CFR 141.80.
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