Section 611.1350  General Requirements

 

a)         Applicability and Scope

 

1)         Applicability and Complying with this Subpart AG.  Subpart G and this Subpart AG constitute NPDWRs for lead and copper.  Subpart G and this Subpart AG apply to all community water systems (CWSs) and non-transient, non-community water systems (NTNCWSs).

 

A)        A supplier must comply with this Subpart AG until the earlier of when the supplier complies with Subpart AG or October 16, 2024.

 

B)        If the Agency issued a SEP prior to December 16, 2021, exempting a supplier under any rule in former Subpart G (now this Subpart AG), the supplier must comply with this Subpart AG until that SEP expires.

 

C)        The Agency may issue a SEP requiring a supplier to comply with specified rules in Subpart G before Section 611.350(a)(1)(A) or (a)(1)(B) otherwise requires or as necessary to address issues in a notice the Agency received from USEPA under 40 CFR 142.23 or 142.30.  The SEP must specify the rules in Subpart G with which the supplier must comply and their counterparts in this Subpart AG with which the supplier needs no longer comply.  The supplier must comply with the SEP-specified Subpart G rules in lieu of their counterparts in this Subpart AG.

 

D)        Relationship Between Subpart G and Subpart AG Rules

 

i)          The rules in this Subpart AG are based on Subpart G as it existed on December 16, 2021, the effective date of USEPA's Lead and Copper Rule Revisions.

 

ii)         Each rule in this Subpart AG corresponds with a rule in Subpart G by adding the digit "1" immediately after "611." in the Section number.  Removing that "1" from the Section number of a rule in this Subpart AG gives the corresponding rule in Subpart G.

 

iii)        Any action under a rule that was in Subpart G before December 16, 2021, satisfies the corresponding rule in this Subpart AG.

 

BOARD NOTE:  USEPA's LCRR apply to all suppliers on December 16, 2021.  However, USEPA delays requiring compliance with LCRR until October 16, 2024, when any previously granted exemption expires, or as provided otherwise by any of several specified rules for corrosion control treatment; lead service line replacement; public education, supplemental monitoring, and mitigation; monitoring; and reporting (corresponding with 35 Ill. Adm. Code 611.351, 611.354, 611.355, 611.356, or 611.360).  Until a supplier must comply with the LCRR, USEPA requires the supplier to comply with subpart I of 40 CFR 141 (2020).  This requires the Board to codify two versions of the Lead and Copper Rule:  one in this Subpart AG, representing the Lead and Copper Rules prior to the LCRR (40 CFR 141 (2020)), and the other in Subpart G, representing 40 CFR 141 incorporating the LCRR.

 

2)         Scope.  This Subpart G establishes a treatment technique including corrosion control treatment, source water treatment, lead service line replacement, and public education.  Lead and copper action levels the supplier measures in samples collected at consumers' taps trigger some of these requirements.

 

b)         Definitions.  For this Subpart AG only, this subsection (b) defines certain terms:

 

"Action level" means the computed concentration of lead or copper in water under subsection (c) determining applicability of some treatment requirements under this Subpart AG.  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 that can reduce 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 corrosion inhibitor in the drinking water sufficient to form a passivating film on the interior walls of pipe.

 

"Exceed" or "exceedance", relative to either the lead or the copper action level, means that the 90th percentile level of the samples the supplier collected during a six-month monitoring period is greater than the lead or copper action level.

 

"First-draw tap sample" means a one-liter sample of tap water, a supplier collects under Section 611.1356(b)(2), that stood in plumbing pipes for at least six hours and the supplier collects without flushing the tap.

 

"Large system" means a water system regularly serving water to more than 50,000 persons.

 

"Lead service line" means a service line made of lead connecting 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 the concentration of lead or copper in finished water entering the supplier's distribution system, which the Agency designates in a SEP based on the contaminant removal ability of the treatment properly operated and maintained.

 

BOARD NOTE:  This definition derives from 40 CFR 141.83(b)(4) (2020).  (See Section 611.1353(b)(4)(B).)

 

"Medium-sized water system" means a water system regularly serving water to 3,301 to 50,000 persons.

 

"Meet" or "comply with", relating 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 lead or copper action level.

 

"Monitoring period" means any of the six-month periods during which a supplier must complete a cycle of monitoring under this Subpart AG.

 

"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 the concentration of lead or copper that ten percent or fewer of all samples tap water samples under Section 611.1356 exceed during a six-month monitoring period (i.e., that contaminant concentration greater than or equal to the results obtained from 90 percent of the samples).  The supplier must determine the 90th percentile levels for copper and lead under subsection (c)(3).

 

BOARD NOTE: This definition derives from 40 CFR 141.80(c) (2020).

 

"Optimal corrosion control treatment" means the corrosion control treatment minimizing the lead and copper concentrations at users' taps while ensuring that the treatment will not 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 analyze 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:  This definition derives from 40 CFR 141.89(a)(1)(ii) and (a)(1)(iv) (2020).

 

"Service line sample" means a one-liter sample of water under Section 611.1356(b)(3) that stood for at least six hours in a service line.

 

"Single-family structure" means a building constructed as a residence for a single-family that the occupant currently uses as a residence or place of business.

 

"Small system" means a water system regularly serving water to 3,300 or fewer persons.

BOARD NOTE:  A small system for purposes of a small system variance under Section 611.131 is distinct from small-sized water system under this Subpart AG.

 

BOARD NOTE:  This subsection (b) derives from 40 CFR 141.2 (2020).

 

c)         Lead and Copper Action Levels

 

1)         The supplier exceeds the lead action level if the 90th percentile lead level is greater than 0.015 mg/L.

 

2)         The supplier exceeds the copper action level if the 90th percentile copper level is greater than 1.3 mg/L.

 

3)         Suppliers must compute the 90th percentile lead and copper levels using the specified procedure:

 

A)        The supplier must list the results of all lead or copper samples it took during the six-month monitoring period in ascending order, ranging from the sample with the lowest concentration to the sample with the highest concentration.  The supplier must assign each sampling result an ordinal number, ascending by single integers, assigning the number 1 for the sample with the lowest contaminant level.  The number the supplier assigns to the sample with the highest contaminant level must equal the total number of samples the supplier took.

 

B)        To determine the 90th percentile sample, the supplier must multiply the total number of samples taken during the six-month monitoring period times 0.9.

 

C)        The contaminant concentration in the sample corresponding with the ordinal number calculating under subsection (c)(3)(B) yields is the 90th percentile contaminant level.

 

D)        For a supplier collecting five samples per six-month monitoring period, the 90th percentile is the average of the highest and second highest concentrations.

 

E)        For a supplier the Agency allows to collect fewer than five samples under Section 611.1356(c), the result for the sample with the highest concentration is the 90th percentile value.

 

d)         Corrosion Control Treatment Requirements

 

1)         Every supplier must install and operate optimal corrosion control treatment.

 

2)         Any supplier complying with the applicable corrosion control treatment requirements the Agency specifies under Sections 611.1351 and 611.1352 is deemed as complying with subsection (d)(1).

 

e)         Source Water Treatment Requirements.  Any supplier whose system exceeds the lead or copper action level must implement all applicable source water treatment requirements the Agency specifies under Section 611.1353.

 

f)         Lead Service Line Replacement Requirements.  Any supplier whose system exceeds the lead action level after implementing applicable corrosion control and source water treatment must complete the lead service line replacement under Section 611.1354.

 

g)         Public Education Requirements.  Under Section 611.1355, the supplier must provide a consumer notice of the lead tap water monitoring results to the persons served at each tested site (tap).  Any supplier exceeding the lead action level must implement the public education requirements.

 

h)         Monitoring and Analytical Requirements.  A supplier must complete all tap water monitoring for lead and copper, monitoring for water quality parameters, and source water monitoring for lead and copper and analyze the monitoring results under this Subpart AG as Sections 611.1356, 611.1357, 611.1358, and 611.1359 require.

 

i)          Reporting Requirements.  A supplier must report any information the treatment provisions of this Subpart AG and Section 611.1360 require to the Agency.

 

j)          Recordkeeping Requirements.  A supplier must maintain records as Section 611.1361 requires.

 

k)         Violation of National Primary Drinking Water Regulations.  Failing to comply with this Subpart AG, including conditions the Agency imposes in a SEP, violates the lead or copper NPDWRs.

 

BOARD NOTE:  This Section corresponds with Section 611.1350 and derives from 40 CFR 141.80 (2020).

 

(Source:  Added at 47 Ill. Reg. 16486, effective November 2, 2023)