484 

§ 141.76 40 CFR Ch. I (7–1–12 Edition) 

with the primacy agency as soon as 

practical, but no later than 24 hours 

after the exceedance is known, in accordance with the public notification 

requirements under §141.203(b)(3). 

(iii) If at any time the residual falls 

below 0.2 mg/l in the water entering the 

distribution system, the system must 

notify the State as soon as possible, 

but no later than by the end of the next 

business day. The system also must notify the State by the end of the next 

business day whether or not the residual was restored to at least 0.2 mg/l 

within 4 hours. 

[54 FR 27527, June 29, 1989, as amended at 65 

FR 26022, May 4, 2000; 69 FR 38856, June 29, 

2004] 

§ 141.76 Recycle provisions. 

(a) Applicability. All subpart H systems that employ conventional filtration or direct filtration treatment and 

that recycle spent filter backwash 

water, thickener supernatant, or liquids from dewatering processes must 

meet the requirements in paragraphs 

(b) through (d) of this section. 

(b) Reporting. A system must notify 

the State in writing by Decemeber 8, 

2003, if the system recycles spent filter 

backwash water, thickener supernatant, or liquids from dewatering 

processes. This notification must include, at a minimum, the information 

specified in paragraphs (b)(1) and (2) of 

this section. 

(1) A plant schematic showing the origin of all flows which are recycled (including, but not limited to, spent filter 

backwash water, thickener supernatant, and liquids from dewatering 

processes), the hydraulic conveyance 

used to transport them, and the location where they are re-introduced back 

into the treatment plant. 

(2) Typical recycle flow in gallons per 

minute (gpm), the highest observed 

plant flow experienced in the previous 

year (gpm), design flow for the treatment plant (gpm), and State-approved 

operating capacity for the plant where 

the State has made such determinations. 

(c) Treatment technique requirement. 

Any system that recycles spent filter 

backwash water, thickener supernatant, or liquids from dewatering 

processes must return these flows 

through the processes of a system’s existing conventional or direct filtration 

system as defined in §141.2 or at an alternate location approved by the State 

by June 8, 2004. If capital improvements are required to modify the recycle location to meet this requirement, 

all capital improvements must be completed no later than June 8, 2006. 

(d) Recordkeeping. The system must 

collect and retain on file recycle flow 

information specified in paragraphs 

(d)(1) through (6) of this section for review and evaluation by the State beginning June 8, 2004. 

(1) Copy of the recycle notification 

and information submitted to the 

State under paragraph (b) of this section. 

(2) List of all recycle flows and the 

frequency with which they are returned. 

(3) Average and maximum backwash 

flow rate through the filters and the 

average and maximum duration of the 

filter backwash process in minutes. 

(4) Typical filter run length and a 

written summary of how filter run 

length is determined. 

(5) The type of treatment provided 

for the recycle flow. 

(6) Data on the physical dimensions 

of the equalization and/or treatment 

units, typical and maximum hydraulic 

loading rates, type of treatment chemicals used and average dose and frequency of use, and frequency at which 

solids are removed, if applicable. 

[66 FR 31103, June 8, 2001] 

Subpart I—Control of Lead and 

Copper 

SOURCE: 56 FR 26548, June 7, 1991, unless 

otherwise noted. 

§ 141.80 General requirements. 

(a) Applicability and effective dates. (1) 

The requirements of this subpart I constitute the national primary drinking 

water regulations for lead and copper. 

Unless otherwise indicated, each of the 

provisions of this subpart applies to 

community water systems and nontransient, non-community water systems (hereinafter referred to as ‘‘water 

systems’’ or ‘‘systems’’). 

(2) [Reserved] 


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Environmental Protection Agency § 141.80 

(b) Scope. These regulations establish 

a treatment technique that includes requirements for corrosion control treatment, source water treatment, lead 

service line replacement, and public 

education. These requirements are 

triggered, in some cases, by lead and 

copper action levels measured in samples collected at consumers’ taps. 

(c) Lead and copper action levels. (1) 

The lead action level is exceeded if the 

concentration of lead in more than 10 

percent of tap water samples collected 

during any monitoring period conducted in accordance with §141.86 is 

greater than 0.015 mg/L (i.e., if the 

‘‘90th percentile’’ lead level is greater 

than 0.015 mg/L). 

(2) The copper action level is exceeded if the concentration of copper in 

more than 10 percent of tap water samples collected during any monitoring 

period conducted in accordance with 

§141.86 is greater than 1.3 mg/L (i.e., if 

the ‘‘90th percentile’’ copper level is 

greater than 1.3 mg/L). 

(3) The 90th percentile lead and copper levels shall be computed as follows: 

(i) The results of all lead or copper 

samples taken during a monitoring period shall be placed in ascending order 

from the sample with the lowest concentration to the sample with the highest concentration. Each sampling result shall be assigned a number, ascending by single integers beginning 

with the number 1 for the sample with 

the lowest contaminant level. The 

number assigned to the sample with 

the highest contaminant level shall be 

equal to the total number of samples 

taken. 

(ii) The number of samples taken 

during the monitoring period shall be 

multiplied by 0.9. 

(iii) The contaminant concentration 

in the numbered sample yielded by the 

calculation in paragraph (c)(3)(ii) is the 

90th percentile contaminant level. 

(iv) For water systems serving fewer 

than 100 people that collect 5 samples 

per monitoring period, the 90th percentile is computed by taking the average of the highest and second highest 

concentrations. 

(v) For a public water system that 

has been allowed by the State to collect fewer than five samples in accordance with §141.86(c), the sample result 

with the highest concentration is considered the 90th percentile value. 

(d) Corrosion control treatment requirements. (1) All water systems shall install and operate optimal corrosion 

control treatment as defined in §141.2. 

(2) Any water system that complies 

with the applicable corrosion control 

treatment requirements specified by 

the State under §§141.81 and 141.82 shall 

be deemed in compliance with the 

treatment requirement contained in 

paragraph (d)(1) of this section. 

(e) Source water treatment requirements. Any system exceeding the lead 

or copper action level shall implement 

all applicable source water treatment 

requirements specified by the State 

under §141.83. 

(f) Lead service line replacement requirements. Any system exceeding the 

lead action level after implementation 

of applicable corrosion control and 

source water treatment requirements 

shall complete the lead service line replacement requirements contained in 

§141.84. 

(g) Public education requirements. Pursuant to §141.85, all water systems 

must provide a consumer notice of lead 

tap water monitoring results to persons served at the sites (taps) that are 

tested. Any system exceeding the lead 

action level shall implement the public 

education requirements. 

(h) Monitoring and analytical requirements. Tap water monitoring for lead 

and copper, monitoring for water quality parameters, source water monitoring for lead and copper, and analyses of the monitoring results under 

this subpart shall be completed in compliance with §§141.86, 141.87, 141.88, and 

141.89. 

(i) Reporting requirements. Systems 

shall report to the State any information required by the treatment provisions of this subpart and §141.90. 

(j) Recordkeeping requirements. Systems shall maintain records in accordance with §141.91. 

(k) Violation of national primary drinking water regulations. Failure to comply 

with the applicable requirements of 

§§141.80–141.91, including requirements 

established by the State pursuant to 

these provisions, shall constitute a violation of the national primary drinking 


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486 

§ 141.81 40 CFR Ch. I (7–1–12 Edition) 

water regulations for lead and/or copper. 

[56 FR 26548, June 7, 1991; 57 FR 28788, June 

29, 1992, as amended at 72 FR 57814, Oct. 10, 

2007] 

§ 141.81 Applicability of corrosion control treatment steps to small, medium-size and large water systems. 

(a) Systems shall complete the applicable corrosion control treatment requirements described in §141.82 by the 

deadlines established in this section. 

(1) A large system (serving >50,000 

persons) shall complete the corrosion 

control treatment steps specified in 

paragraph (d) of this section, unless it 

is deemed to have optimized corrosion 

control under paragraph (b)(2) or (b)(3) 

of this section. 

(2) A small system (serving ≤3300 persons) and a medium-size system (serving >3,300 and ≤50,000 persons) shall 

complete the corrosion control treatment steps specified in paragraph (e) of 

this section, unless it is deemed to 

have optimized corrosion control under 

paragraph (b)(1), (b)(2), or (b)(3) of this 

section. 

(b) A system is deemed to have optimized corrosion control and is not required to complete the applicable corrosion control treatment steps identified in this section if the system satisfies one of the criteria specified in 

paragraphs (b)(1) through (b)(3) of this 

section. Any such system deemed to 

have optimized corrosion control under 

this paragraph, and which has treatment in place, shall continue to operate and maintain optimal corrosion 

control treatment and meet any requirements that the State determines 

appropriate to ensure optimal corrosion control treatment is maintained. 

(1) A small or medium-size water system is deemed to have optimized corrosion control if the system meets the 

lead and copper action levels during 

each of two consecutive six-month 

monitoring periods conducted in accordance with §141.86. 

(2) Any water system may be deemed 

by the State to have optimized corrosion control treatment if the system 

demonstrates to the satisfaction of the 

State that it has conducted activities 

equivalent to the corrosion control 

steps applicable to such system under 

this section. If the State makes this 

determination, it shall provide the system with written notice explaining the 

basis for its decision and shall specify 

the water quality control parameters 

representing optimal corrosion control 

in accordance with §141.82(f). Water 

systems deemed to have optimized corrosion control under this paragraph 

shall operate in compliance with the 

State-designated optimal water quality 

control parameters in accordance with 

§141.82(g) and continue to conduct lead 

and copper tap and water quality parameter sampling in accordance with 

§141.86(d)(3) and §141.87(d), respectively. 

A system shall provide the State with 

the following information in order to 

support a determination under this 

paragraph: 

(i) The results of all test samples collected for each of the water quality parameters in §141.82(c)(3). 

(ii) A report explaining the test 

methods used by the water system to 

evaluate the corrosion control treatments listed in §141.82(c)(1), the results 

of all tests conducted, and the basis for 

the system’s selection of optimal corrosion control treatment; 

(iii) A report explaining how corrosion control has been installed and how 

it is being maintained to insure minimal lead and copper concentrations at 

consumers’ taps; and 

(iv) The results of tap water samples 

collected in accordance with §141.86 at 

least once every six months for one 

year after corrosion control has been 

installed. 

(3) Any water system is deemed to 

have optimized corrosion control if it 

submits results of tap water monitoring conducted in accordance with 

§141.86 and source water monitoring 

conducted in accordance with §141.88 

that demonstrates for two consecutive 

6-month monitoring periods that the 

difference between the 90th percentile 

tap water lead level computed under 

§141.80(c)(3), and the highest source 

water lead concentration is less than 

the Practical Quantitation Level for 

lead specified in §141.89(a)(1)(ii). 

(i) Those systems whose highest 

source water lead level is below the 

Method Detection Limit may also be 

deemed to have optimized corrosion 

control under this paragraph if the 90th 


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