Section 611.350  General Requirements and Action Levels

 

a)         Applicability, effective date, compliance deadlines, and scope.  The requirements for Subparts G, AG, and AH constitute NPDWRs for lead and copper.

 

1)         This Subpart G, Subpart AG, and Subpart AH apply to community water systems (CWSs) and non-transient, non-community water systems (NTNCWSs) as defined in Section 611.101.

 

2)         The requirements of this subpart are effective within 30 days of the effective date of this Subpart G.

 

3)         Community water system suppliers and non-transient non-community water system suppliers must comply with the requirements of this subpart G no later than November 1, 2027, except where otherwise specified in Sections 611.351, 611.354, 611.355, 611.356, and 611.360 or where an exemption in compliance with 40 CFR part 142, subpart C or F, has been issued by the Agency.

 

4)         Compliance Dates

 

A)        Between October 30, 2024, and November 1, 2027, community water systems and non-transient non-community water systems must comply with Subpart AH Sections 611.2350(b), 611.840(d), and 611.2350 through 611.2361, except systems must also comply with this subpart G Sections 611.354(a)(1) through (10) (excluding paragraphs (a)(6) and (7)), 611.355(a)(1)(B) and (e), Section 611.360(e)(1) and (13), (f)(4), and (h)(3); Subpart V Sections 611.901(a)(3)(F), and (c)(3), and 611.902(a)(10); Section 611.Appendix G, entry I.C.1 (excluding Section 611.360, except paragraphs (e)(1) and (13) and (f)(4)) and entry I.C.2; Section 611.Appendix H, entry D.23; and Section 611.840(d)(2) within 30 days of the effective date of this subpart G.

 

B)        If an exemption from Subpart AG was issued in compliance with 40 CFR 142, subpart C or F, prior to December 15, 2021 then the supplier must comply with Sections 611.1350 to 611.1361 as codified in Subpart AG until the expiration of the exemption.

 

BOARD NOTE:  This subsection (a) derives from 40 CFR 141.80(a).  USEPA's Lead and Copper Rule Improvements (LCRI) apply to all suppliers on November 1, 2027.  However, USEPA delays complying with LCRI until November 1, 2027, 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, 622.354, 611.355, 611.356, or 611.360).  Until a supplier must comply with the LCRI, USEPA requires the supplier to comply with subpart I of 40 CFR 141 (2024).  This requires the Board to codify three versions of the Lead and Copper Rule:  one in Subpart AG, representing the Lead and Copper Rules prior to the LCRR (40 CFR 141 (2020)), one in Subpart AH representing the Lead and Copper Rules prior to the LCRI (40 CFR 141 (2024) and the other in this Subpart G, representing 40 CFR 141 incorporating the LCRI.

 

5)         Scope.  The regulations in this Subpart G constitute a treatment technique rule that includes treatment techniques to control corrosion, treat source water, replace service lines, and provide public education. The regulations in this subpart include requirements to support the treatment technique including a service line inventory, tap sampling, and monitoring for lead in schools and childcare facilities.  Some of the requirements in this subpart only apply if there is an exceedance of the lead or copper action levels, specified in subsection (c), as measured in samples collected at consumers' taps.

 

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

 

"Action level" means the concentrations of lead or copper in water under subsection (c) determining applicability of some treatment requirements under this Subpart G.  The action level for lead is 0.010 mg/L, and the action level for copper is 1.3 mg/L.

 

"Aerator" means the device embedded in a water faucet to enhance air flow in the water stream and prevent splashing.

 

"Childcare facility" means a location that houses a provider of childcare, day care, or early learning services to children as licensed by the State, local, or Tribal licensing agency.

BOARD NOTE:  See, e.g., the Childcare Act of 1969 [225 ILCS 10].

 

"Connector, also referred to as a gooseneck or pigtail" means a short segment of piping, not exceeding three feet that can be bent and is used for connections between service piping, typically connecting the service line to the main.  For purposes of this subpart G, lead connectors are not considered to be part of the service line.

 

"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.

 

"Distribution system and site assessment" means the requirements under this Subpart G under Section 611.352(j) that water systems must perform at every tap sampling site yielding a lead result above 0.010 mg/ L.

 

"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.

 

"Elementary school" means a school classified as elementary by State and local practice and composed of any span of grades (including pre-school) not above grade 8.

 

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

 

"Fifth-liter sample" means a one-liter sample of tap water collected in compliance with Section 611.356(b).

 

"First-liter sample" means a sample collected of the first one-liter volume of tap water drawn in compliance with Section 611.356(b).

 

"Galvanized requiring replacement service line" means a galvanized service line that currently is or ever was downstream of a lead service line; or is currently downstream of a lead status unknown service line.  For this definition, downstream means in the direction of flow through the service line.  If the supplier is unable to demonstrate that the galvanized service line was never downstream of a lead service line, it is a galvanized requiring replacement service line for purposes of the service line inventory and replacement requirements in Section 611.354.

 

BOARD NOTE:  This definition derives from 40 CFR 141.84.

 

"Galvanized service line" means a service line that is made of iron or steel that has been dipped in zinc to prevent corrosion and rusting.

 

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

 

"Lead service line" means a service line that is made of lead or where a portion of the service line is made of lead.  A lead-lined galvanized service line is defined as a lead service line.

 

"Lead status unknown service line" means a service line whose pipe material has not been demonstrated to be a lead service line, galvanized requiring replacement service line, or a non-lead service line in compliance with Section 611.354(a)(3).

 

"Lead trigger level" means a particular concentration of lead in water that prompts certain activities under this Subpart G.  The trigger level for lead is a concentration of 10 µg/L.

 

"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). (See Section 611.353(b)(4)(B).)

 

"Meet" or "comply with", relating to either the lead or the copper action level, means that the 90^th percentile concentration of the supplier's samples collected during a six-month tap monitoring period is less than or equal to the lead or copper action level.

 

"Medium supplier" means a supplier that serves water to greater than 10,000 persons and less than or equal to 50,000 persons.

 

"Multiple-family residence" means a building in which multiple families currently reside, but not one that is also a "single-family structure".

 

"Newly regulated public water system" refers to either: 

 

1)         An existing public water system that was not subject to National Primary Drinking Water Regulations on October 16, 2024, because the system met the requirements of section 1411 of the Safe Drinking Water Act and Section 611.100(d); or

 

2)         An existing water system that did not meet the definition of a public water supplier in Section 611.101 on October 16, 2024. This term does not include existing water systems under new or restructured ownership or management.

 

BOARD NOTE:  This definition derives from 40 CFR 141.2

 

"90^th percentile concentration" means the concentration of lead or copper the supplier computes under subsection (c)(4) using the results of tap water sampling under Section 611.356.

 

BOARD NOTE:  This definition derives from 40 CFR 141.80(c)(4).

 

"Optimal corrosion control treatment" or "OCCT" 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 in this subpart.

 

"Partial service line replacement" means replacement of any portion of a lead service line or galvanized requiring replacement service line as defined in this section, that leaves in service any length of the lead or galvanized requiring replacement service line upon completion of the work.

 

"Pitcher filter" means a non-plumbed water filtration device consisting of a gravity-fed water filtration cartridge and a filtered drinking water reservoir certified by an American National Standards Institute accredited certifier to reduce lead in drinking water.

 

BOARD NOTE:  NSF/ANSI 53 is the health-based standard for lead and several other contaminants for water filter devices, including pitcher filter-type devices.  Identifying a device as certified under NSF/ANSI 53 at the time of purchase is possible.  NSF maintains an on-line list of certified devices at info.nsf.org/Certified/dwtu/listings_leadreduction.asp.  See the definition of "accredited third-party certification body" in 35 Ill. Adm. Code 611.126(b) relating to NSF/ANSI 372.

 

"Practical quantitation limit" or "PQL" means the lowest concentration of an analyte (substance) that a well-operated laboratory can measure with a high degree of confidence that the analyte is present at or above that concentration.

 

BOARD NOTE:  This definition derives from 40 CFR 141.89(a)(1)(ii) and (a)(1)(iv).

 

"Pre-stagnation flushing" means opening taps to flush standing water from plumbing before a minimum six-hour stagnation period before lead and copper tap sampling under Subpart G.

 

"School" means any building or building complex associated with public, private, or charter institutions that primarily provides teaching and learning for elementary or secondary students.

 

"Secondary school" means a school comprising any span of grades beginning with the next grade following an elementary school (usually 7, 8, or 9) and ending with grade 12.  Secondary schools include both junior high schools and senior high schools and typically span grades 7 through 12.

 

"Service line" means a portion of pipe that connects the water main (or other conduit for distributing water to individual consumers or groups of consumers) to the building inlet.  Where a building is not present, the service line connects the water main (or other conduit for distributing water to individual consumers or groups of consumers) to the outlet.

 

"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 supplier" or "small CWS supplier" means a CWS serving 10,000 or fewer persons.

 

BOARD NOTE:  A small CWS is a small supplier that is a CWS.  This definition derives from the preamble of 40 CFR 141.93.  Corresponding Section 611.363 distinguishes a small CWS supplier from an NTNCWS supplier.

 

"Small supplier" means a supplier regularly serving water to 10,000 or fewer persons.

BOARD NOTE:  USEPA did not revise its corresponding definition of "small water system" in 40 CFR 141.2 from 3,300 or fewer to 10,000 or fewer persons.  This creates an inconsistency the Board corrected.

 

"Source water monitoring period" means any of the six-month periods during which a supplier must complete source water monitoring under Section 611.358.

 

BOARD NOTE:  The Board added this definition to avoid confusion with "tap sampling period," "tap monitoring period", and "water quality monitoring period", as used under this Subpart G, and "compliance period" and "compliance cycle", as used elsewhere in this Part and Section 611.101 defines.

 

"Supplier without corrosion control treatment" means a water system supplier that does not have or purchases all of its water from a supplier that does not have:

 

An optimal corrosion control treatment approved by the Agency; or

 

Any pH adjustment , alkalinity adjustment, and/or corrosion inhibitor addition resulting from other water quality adjustments as part of its treatment train infrastructure.

 

"Tap monitoring period" means the period of time during which each supplier must conduct tap sampling for lead and copper analyses.  The applicable tap monitoring period is determined by lead and copper concentrations in tap samples.  The length of the tap monitoring period can range from six months to nine years.

 

"Tap sampling period" means the time period within a tap monitoring period, within a tap monitoring period, during which the supplier is required to collect samples for lead and copper analysis.

 

BOARD NOTE:  "Tap sampling period" describes when the supplier collects samples.

 

"Tap sampling protocol" means the method for collecting tap samples under Section 611.356(b).

 

"Water quality monitoring period" means any of the six-month periods during which a supplier must complete a cycle of tap and entry point water quality monitoring under Section 611.357.

 

BOARD NOTE:  The Board added this definition.  USEPA refers to these as "monitoring periods".  The Board uses "water quality monitoring period" to avoid confusion with "tap sampling period," "tap monitoring period", and "source water monitoring period", as used under this Subpart G, and "compliance period" and "compliance cycle", as used elsewhere in this Part and Section 611.101 defines.

 

"Wide-mouthed bottles" means bottles one liter in volume having a mouth that is at least 40 mm wide.

 

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

 

c)         Lead and copper action levels and method for determining whether there is an exceedance of the action level.  A supplier must determine action levels based on tap water samples that must be considered for inclusion under Section 611.356(e) for the purpose of calculating the 90^th percentile and tested using the analytical methods specified in Section 611.359.  The action levels described in this subsection (c) are applicable to all sections of Subpart G.  Action levels for lead and copper are as follows:

 

1)         The supplier exceeds the lead action level if the 90^th percentile concentration of lead derived as specified in subsection (c)(3) is greater than 0.010 mg/L.

 

2)         The supplier exceeds the copper action level if the 90^th percentile concentration of copper as specified in subsection (c)(3) is greater than 1.3 mg/L.

 

3)         For purposes of this subpart, the 90^th percentile concentration must be derived as follows:

 

A)        For suppliers that do not have Tier 1 and/or Tier 2 sites and only have sites identified as Tier 3, 4, or 5 under Section 611.356(a):

 

i)          The results of all lead or copper samples taken during a tap sampling period and eligible for inclusion in the 90^th percentile calculation under Section 611.356(e) must be placed in ascending order from the sample with the lowest concentration of lead or copper to the sample with the highest concentration of lead or copper. Each sampling result must be assigned a number, in ascending order beginning with the number 1 for the sample with the lowest concentration of lead or copper. The number assigned to the sample with the highest concentration must be equal to the total number of samples taken and considered for inclusion in the 90^th percentile calculation, in compliance with Section 611.356(e).

 

ii)         The number of samples taken during the tap sampling period must be multiplied by 0.9.

 

iii)        The 90^th percentile concentration is the concentration of lead or copper in the numbered sample yielded after multiplying the number of samples by 0.9 in subsection (c)(3)(A)(ii).

 

iv)        For suppliers that collect five samples per tap sampling period, the 90^th percentile concentration is the average of the highest and second highest concentration from the results in subsection (c)(3)(A)(i).

 

v)         For a supplier that is allowed by the Agency to collect fewer than five samples in compliance with Section 611.356(a)(2) or fails to meet their required minimum number of samples and collected fewer than five samples, the samples result with the highest concentration from the results in subsection (c)(3)(A)(i) is considered the 90^th percentile value.

 

B)        For suppliers with sites identified as Tier 1 or 2 under Section 611.356(a) with sufficient Tier 1 and 2 sites to meet the minimum number of sites required in Section 611.356(c) or (d) as applicable:

 

i)          For lead, suppliers must include the higher of the first-liter and fifth-liter lead sample results at each Tier 1 and 2 site (or first-liter lead sample if tiering is based on premise plumbing) taken during the tap sampling period in subsections (c)(3)(B)(ii) through (iv).  For copper, suppliers must include all first-liter copper samples collected at each Tier 1 and 2 site taken during the tap sampling period.  Lead or copper sample results from Tier 3, 4, or 5 sites cannot be included in this calculation.

 

ii)         The results of the lead or copper samples taken during a tap sampling period and eligible for inclusion in the 90^th percentile calculation under Section 611.356(e) identified in subsection (c)(3)(B)(i) must be placed in ascending order from the sample with the lowest concentration to the sample with the highest concentration. Each sampling result must be assigned a number, in ascending order beginning with the number 1 for the sample with the lowest concentration. The number assigned to the sample with the highest concentration must be equal to the total number of samples.

 

iii)        The number of samples identified in subsection (c)(3)(B)(ii) must be multiplied by 0.9.

 

iv)        The 90^th percentile concentration is the concentration of lead or copper in the numbered sample yielded after multiplying the number of samples by 0.9 in subsection (c)(3)(B)(iii).

 

v)         For suppliers that collect samples from five sites per tap sampling period, the 90^th percentile concentration is the average of the highest and second highest concentration from the results in subsection (c)(3)(B)(ii).

 

vi)        For a supplier allowed by the Agency to collect fewer than five copper samples or five first-liter and fifth-liter-paired lead samples in compliance with Section 611.356(a)(2), or has failed to collect at least five copper samples or five first-liter and fifth-liter-paired lead samples, the sample result with the highest concentration from the results in paragraph (c)(3)(B)(ii) is considered the 90^th percentile value.

 

C)        For suppliers with sites identified as Tier 1 or 2 under Section 611.356(a) with an insufficient number of Tier 1 or 2 sites to meet the minimum number of sites required in Section 611.356(c) or (d) as applicable:

 

i)          For lead, the supplier must use the higher value of the first-liter and fifth-liter lead sample for each Tier 1 or 2 site (or first-liter lead sample if tiering is based on premise plumbing) and the first-liter lead samples from sites in the next highest available tier (i.e., Tier 3, 4, and 5) to meet the minimum number of sites required in Section 611.356(c) or (d) sampled during a tap sampling period for the steps in subsections (c)(3)(C)(ii) through (iv).  For copper, the supplier must use all first-liter copper samples collected.

 

ii)         The results of all of the lead or copper samples identified in subsection (c)(3)(C)(i) must be placed in ascending order from the sample with the lowest concentration to the sample with the highest concentration.  The supplier must reduce this list to only include samples with the highest concentrations such that the number of sample results equals the minimum number of sites required to be sampled by Section 611.356(c) or (d), as applicable.  From this reduced list, each sampling result must be assigned a number, in ascending order beginning with the number 1 for the sample with the lowest concentration. The number assigned to the sample with the highest concentration must be equal to the minimum number of sites required by Section 611.356(c) or (d), as applicable.

 

iii)        The number of samples identified in subsection (c)(3)(C)(ii) must be multiplied by 0.9.

 

iv)        The 90^th percentile concentration is the concentration of lead or copper in the numbered sample yielded after multiplying the number of samples by 0.9 in subsection (c)(3)(C)(iii).

 

v)         For suppliers that collect samples from five sites per tap sampling period, the 90^th percentile concentration is the average of the highest and second highest concentration from the results in subsection (c)(3)(C)(ii).

 

vi)        For a supplier that is allowed by the Agency to collect fewer than five copper samples or five first-liter and fifth-liter-paired lead samples in compliance with Section 611.356(a)(2), or has failed to collect at least five copper samples or five first-and-fifth-liter-paired lead samples, the sample result with the highest concentration from the results in subsection (c)(3)(C)(ii) is considered the 90^th percentile value.

 

vii)       If a supplier does not collect enough samples sufficient to meet the minimum number of sites required in Section 611.356(c) or (d), the suppler must calculate the 90^th percentile lead and copper levels following the steps in Section 611.350(c)(3)(A)(i) through (iii).

 

BOARD NOTE:  This Section derives from 40 CFR 141.80.

 

(Source:  Amended at 50 Ill. Reg. 2531, effective February 17, 2026)