§141.2. Definitions. — Inbound Citations

(1) You receive the water from a public water system, as defined under the Safe Drinking Water Act (SDWA) regulations, 40 CFR part 141, that furnishes water that meets the microbial requirements under those regulations or under the regulations of a State (as defined in 40 CFR 141.2) approved to administer the SDWA public water supply program, and you have public water system results or certificates of compliance that demonstrate that the water meets those microbial requirements;

(ii) The name of water from a subsurface saturated zone that is under a pressure equal to or greater than atmospheric pressure is “ground water.” Ground water must not be under the direct influence of surface water as defined in 40 CFR 141.2.

(4) Use only water from a U.S. public water system (PWS), as defined in 40 CFR 141.2 and that meets the requirements of 40 CFR parts 141 and 143, as ballast water. Vessels using water from a PWS as ballast must maintain a record of which PWS they received the water and a receipt, invoice, or other documentation from the PWS indicating that water came from that system. Furthermore, they must certify that they have met the conditions in paragraphs (a)(4)(i) or (ii) of this section, as applicable. Vessels using water from a PWS must use such water exclusively for all ballast water unless the usage is in accordance with § 151.1515 of this subpart. Vessels using PWS water as ballast must have either—

(i) Previously cleaned the ballast tanks (including removing all residual sediments) and not subsequently introduced ambient water; or

(2) Use only water from a U.S. public water system (PWS), as defined in 40 CFR 141.2, that meets the requirements of 40 CFR parts 141 and 143 as ballast water. Vessels using water from a PWS as ballast must maintain a record of which PWS they received the water from as well as a receipt, invoice, or other documentation from the PWS indicating that water came from that system. Furthermore, they must certify that they have met the conditions in paragraphs (a)(2)(i) or (ii) of this section, as applicable, and describe in the BWM plan the procedures to be used to ensure compliance with those conditions, and thereafter document such compliance in the BW record book. Vessels using water from a PWS must use such water exclusively unless the usage is in accordance with § 151.2040 of this subpart. Vessels using PWS water as ballast must have either—

(i) Previously cleaned the ballast tanks (including removing all residual sediments) and not subsequently introduced ambient water; or

The following definitions apply to terms used in this subpart:

(4) Any other specific arrangement approved by the Regional Administrator upon request of the owner or operator.

CWA Hazardous Substance means any hazardous substance designated in 40 CFR part 116.

Discharge includes, but is not limited to, any spilling, leaking, pumping, pouring, emitting, emptying, or dumping of a CWA hazardous substance, but excludes: discharges in compliance with a permit under section 402 of the CWA; discharges resulting from circumstances identified, reviewed, and made a part of the public record with respect to a permit issued or modified under section 402 of the CWA, and subject to a condition in such permit; and continuous or anticipated intermittent discharges from a point source, identified in a permit or permit application under section 402 of the CWA, that are caused by events occurring within the scope of relevant operating or treatment systems.

Distance to the endpoint means the greatest distance a CWA hazardous substance in a worst case discharge into or on the navigable waters or a conveyance to navigable waters can travel while still having the ability to cause injury to public receptors or fish, wildlife, and sensitive environments, as determined under § 118.3(c)(1) and (c)(3) using endpoint concentrations enumerated in Appendix B or adversely impact a public water system as in § 118.3(c)(2).

Endpoint means the concentration at which a worst case discharge of a CWA hazardous substance has the ability to cause injury to public receptors or fish, wildlife, and sensitive environments as in Appendix B or adversely impact a public water system as in § 118.3(c)(2).

Exclusive economic zone means the zone contiguous to the territorial sea of the United States extending to a distance up to 200 nautical miles from the baseline from which the breadth of the territorial sea is measured.

Facility means any mobile or fixed building, property, parcel, lease, structure, installation, equipment, pipe, or in-plant pipeline (other than a vessel or a public vessel), used in CWA hazardous substance handling, production, manufacturing, storage, processing, refining, transfer, distribution, treatment, or in which any CWA hazardous substance is used. The boundaries of a facility depend on several site-specific factors, including but not limited to, the ownership or operation of buildings, structures, and equipment on the same site and types of activity at the site. Therefore, contiguous or non-contiguous buildings, properties, parcels, leases, structures, installations, pipes, or pipelines under the ownership or operation of the same person may, for legitimate operational and response planning reasons, be considered separate facilities.

Fish, wildlife, and sensitive environments mean areas that may be identified by their legal designation or by evaluations of Area Committees (for planning) or members of the Federal On-Scene Coordinator's spill response structure (during responses). These areas may include wetlands, national and State parks, critical habitats for endangered or threatened species, wilderness and natural resource areas, marine sanctuaries and estuarine reserves, conservation areas, preserves, wildlife areas, wildlife refuges, wild and scenic rivers, recreational areas, national forests, Federal and State lands that are research national areas, heritage program areas, land trust areas, and historical and archaeological sites and parks. These areas may also include unique habitats such as aquaculture sites and agricultural surface water intakes, bird nesting areas, critical biological resource areas, designated migratory routes, and designated seasonal habitats.

Injury means a measurable adverse change, either long- or short-term, in the chemical or physical quality or the viability of a natural resource or public receptor (including to human health) resulting either directly or indirectly from exposure to a discharge, or exposure to a product of reactions (e.g., more hazardous degradation products, ignition, or reaction) resulting from a discharge.

Interconnected containers mean containers that are connected via pipes, hoses, or other conveyance (either permanent or temporary) to allow movement of a CWA hazardous substance between containers.

Maximum extent practicable means within the limitations used to determine CWA hazardous substance release planning resources for recovery, shoreline protection, and cleanup for worst case discharges from onshore non-transportation-related facilities in adverse weather. It includes the planned capability to respond to a worst case discharge, including a discharge resulting from fire or explosion, as contained in a facility response plan that meets the requirements in § 118.11 or in a specific plan approved by the Regional Administrator.

Maximum quantity onsite means the maximum total aggregate quantity for each CWA hazardous substance present at all locations within the entire non-transportation-related onshore facility at any time.

Mitigation or mitigation system(s) means specific activities, technologies, or equipment designed or deployed to capture or control substances upon loss of containment to minimize exposure of the public or the environment. Passive mitigation means equipment, devices, or technologies that function without human, mechanical, or other energy input.

Navigable waters mean waters of the United States as defined in 40 CFR 120.2, adjoining shorelines, and the exclusive economic zone.

Non-transportation-related onshore facility means any facility of any kind located in, on, or under any land within the United States and excludes movement of CWA hazardous substances in interstate or intrastate commerce under active shipping papers by rail, pipeline, highway vehicle, or vessel pursuant to 49 CFR parts 171-180.

Offshore facility means any facility of any kind (other than a vessel or public vessel) located in, on, or under any of the navigable waters of the United States, and any facility of any kind that is subject to the jurisdiction of the United States and is located in, on, or under any other waters.

Offsite means areas beyond the property boundary of a facility, and areas within the property boundary to which the public has routine and unrestricted access during or outside business hours.

Onshore facility means any facility of any kind located in, on, or under any land within the United States other than submerged land. Furthermore, this extends to in, on, or under any submerged land as delegated to the Environmental Protection Agency (EPA) pursuant to 40 CFR part 112 Appendix B.

Owner or operator means any person owning or operating an onshore facility or an offshore facility, and in the case of any abandoned offshore facility, the person who owned or operated or maintained the facility immediately prior to such abandonment.

Person means an individual, firm, corporation, association, or partnership.

Planning distance means the distance to an endpoint such that a worst case discharge of CWA hazardous substances into or on the navigable waters or a conveyance to navigable waters from a non-transportation-related onshore facility could adversely impact a public water system or cause injury to fish, wildlife, and sensitive environments or public receptors, as described in § 118.10.

Publicly Owned Treatment Works is defined in 40 CFR 403.3 and includes Federally Owned Treatment Works.

Public receptors mean parks, recreational areas, docks, or other public spaces inhabited, occupied, or used by the public at any time where members of the public could be injured as a result of a worst case discharge into or on the navigable waters or a conveyance to navigable waters.

Public vessel as defined by section 311(a)(4) of the CWA means a vessel owned or bareboat-chartered and operated by the United States, or a State or political subdivision thereof, or by a foreign nation, except when such vessel is engaged in commerce.

Public water system is a system as defined in 40 CFR 141.2. A public water system is either a “community water system” or a “non-community water system.”

Qualified individual (QI) means the individual having full authority to implement response actions and required to initiate immediate communications with the appropriate Federal official and the persons providing personnel and equipment to respond, to the maximum extent practicable, to a worst case discharge and to mitigate or prevent a substantial threat of such a discharge.

Regional Administrator means the Regional Administrator of the EPA, in and for the Region in which the non-transportation-related onshore facility is located.

Reportable quantities mean quantities that may be harmful as set forth in § 117.3, the discharge into the environment during a 24-hour period, which is a violation of Clean Water Act section 311(b)(3) and requires notice as set forth in § 117.21.

Respond or response means containment, removal, remediation, neutralization, source control, mechanical recovery, bioremediation, or other release countermeasures, in accordance with the applicable Regional Contingency Plan and Area Contingency Plan, of the CWA hazardous substances from the water and adjoining shorelines or the taking of such other actions that may be necessary to prevent, minimize, or mitigate damage to the environment, public health, or welfare, including, but not limited to, persons, fish, shellfish, wildlife, public water systems, and public and private property, shorelines, and beaches.

Response equipment means equipment (including firefighting equipment), or other mitigating substances and devices, available to an owner or operator and Federal, State, and local or Tribal agencies, designed or used to ensure an effective and immediate response to a discharge, and to ensure mitigation or prevention of a substantial threat of a discharge.

Response resources means the personnel, equipment, supplies, and other capability necessary to perform the response activities identified in the facility response plan required under this part.

Source water protection area means the area delineated by the State for a public water system or including numerous public water systems, whether the source is ground water or surface water or both, as part of the State Source Water Assessment Program approved by EPA under section 1453 of the Safe Drinking Water Act (42 U.S.C. 300j-13).

Spill response organization (SRO) means an entity that provides spill response resources to mitigate or remove CWA hazardous substances from the environment and mitigate associated impacts.

Transportation or transport means the movement of property and loading, unloading, or storage incidental to movement pursuant to 49 CFR part 171-199.

Transportation-related onshore facility means any facility of any kind, in, on, or under any land within the United States which provides movement or conveyances of CWA hazardous substances in interstate or intrastate commerce by rail, pipeline, highway vehicle, or vessel pursuant to 49 CFR parts 171-199.

United States means the States, the District of Columbia, the Commonwealth of Puerto Rico, the Commonwealth of the Northern Mariana Islands, Guam, American Samoa, the U.S. Virgin Islands, and the Pacific Island Governments.

Vessel as defined by section 101(28) of the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA), means every description of watercraft or other artificial contrivance used, or capable of being used, as a means of transportation on water; and, as defined by section 311(a)(3) of the CWA, means every description of watercraft or other artificial contrivance used, or capable of being used, as a means of transportation on water other than a public vessel.

Water distribution system means a system to connect water treatment plants or water sources (in the absence of treatment) to customers via a network of pipes, storage facilities, valves, and pumps.

Wellhead protection area means the surface and subsurface area surrounding a water well or wellfield, supplying a public water system, through which contaminants are reasonably likely to move toward and reach such water well or wellfield.

Worst case discharge means the largest foreseeable discharge in adverse weather conditions including a discharge resulting from fire or explosion.

(1) Subpart H systems which use conventional filtration treatment (as defined in § 141.2) must monitor each treatment plant for TOC no later than the point of combined filter effluent turbidity monitoring and representative of the treated water. All systems required to monitor under this paragraph (d)(1) must also monitor for TOC in the source water prior to any treatment at the same time as monitoring for TOC in the treated water. These samples (source water and treated water) are referred to as paired samples. At the same time as the source water sample is taken, all systems must monitor for alkalinity in the source water prior to any treatment. Systems must take one paired sample and one source water alkalinity sample per month per plant at a time representative of normal operating conditions and influent water quality.

(1) Subpart H systems using conventional filtration treatment (as defined in § 141.2) must operate with enhanced coagulation or enhanced softening to achieve the TOC percent removal levels specified in paragraph (b) of this section unless the system meets at least one of the alternative compliance criteria listed in paragraph (a)(2) or (a)(3) of this section.

(2) An existing water system that did not meet the definition of a public water system in § 141.2 on October 16, 2024. This term does not include existing water systems under new or restructured ownership or management.

Non-community water system means a public water system that is not a community water system. A non-community water system is either a “transient non-community water system (TWS)” or a “non-transient non-community water system (NTNCWS).”

Non-transient non-community water system or NTNCWS means a public water system that is not a community water system and that regularly serves at least 25 of the same persons over 6 months per year.

Optimal corrosion control treatment (OCCT), for the purpose of subpart I of this part only, 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 part.

Partial service line replacement, for the purpose of subpart I of this part only, 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 lead or galvanized requiring replacement service line upon completion of the work.

Performance evaluation sample means a reference sample provided to a laboratory for the purpose of demonstrating that the laboratory can successfully analyze the sample within limits of performance specified by the Agency. The true value of the concentration of the reference material is unknown to the laboratory at the time of the analysis.

Person means an individual; corporation; company; association; partnership; municipality; or State, Federal, or tribal agency.

PFBS means Chemical Abstract Service registration number 45187-15-3, chemical formula C4F9SO3-, perfluorobutane sulfonate, along with its conjugate acid and any salts, derivatives, isomers, or combinations thereof.

PFHxS means Chemical Abstract Service registration number 108427-53-8, chemical formula C6F13SO3-, perfluorohexane sulfonate, along with its conjugate acid and any salts, derivatives, isomers, or combinations thereof.

PFNA means Chemical Abstract Service registration number 72007-68-2, chemical formula C9F17O2-, perfluorononanoate, along with its conjugate acid and any salts, derivatives, isomers, or combinations thereof.

PFOA means Chemical Abstract Service registration number 45285-51-6, chemical formula C8F15O2-, perfluorooctanoate, along with its conjugate acid and any salts, derivatives, isomers, or combinations thereof.

PFOS means Chemical Abstract Service registration number 45298-90-6, chemical formula C8F17SO3-, perfluorooctanesulfonate, along with its conjugate acid and any salts, derivatives, isomers, or combinations thereof.

Picocurie (pCi) means the quantity of radioactive material producing 2.22 nuclear transformations per minute.

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

Plant intake refers to the works or structures at the head of a conduit through which water is diverted from a source (e.g., river or lake) into the treatment plant.

Point of disinfectant application is the point where the disinfectant is applied and water downstream of that point is not subject to recontamination by surface water runoff.

Point-of-entry treatment device (POE) is a treatment device applied to the drinking water entering a house or building for the purpose of reducing contaminants in the drinking water distributed throughout the house or building.

Point-of-use treatment device or point of use device (POU) is a water treatment device physically installed or connected to a single fixture, outlet, or tap to reduce or remove contaminants in drinking water. For the purposes of subpart I of this part, it must be certified by an American National Standards Institute accredited certifier to reduce lead in drinking water.

Practical quantitation limit (PQL) means the minimum concentration of an analyte (substance) that can be measured with a high degree of confidence that the analyte is present at or above that concentration.

Presedimentation is a preliminary treatment process used to remove gravel, sand and other particulate material from the source water through settling before the water enters the primary clarification and filtration processes in a treatment plant.

Pre-stagnation flushing is the opening of tap(s) to flush standing water from plumbing prior to the minimum 6-hour stagnation period in anticipation of lead and copper tap sampling under subpart I of this part.

Public water system means a system for the provision to the public of water for human consumption through pipes or, after August 5, 1998, other constructed conveyances, if such system has at least fifteen service connections or regularly serves an average of at least twenty-five individuals daily at least 60 days out of the year. Such term includes: any collection, treatment, storage, and distribution facilities under control of the operator of such system and used primarily in connection with such system; and any collection or pretreatment storage facilities not under such control which are used primarily in connection with such system. Such term does not include any “special irrigation district.” A public water system is either a “community water system” or a “noncommunity water system.”

Rem means the unit of dose equivalent from ionizing radiation to the total body or any internal organ or organ system. A “millirem (mrem)” is 1/1000 of a rem.

Repeat compliance period means any subsequent compliance period after the initial compliance period.

Residual disinfectant concentration (“C” in CT calculations) means the concentration of disinfectant measured in mg/l in a representative sample of water.

Sanitary defect is a defect that could provide a pathway of entry for microbial contamination into the distribution system or that is indicative of a failure or imminent failure in a barrier that is already in place.

Sanitary survey means an onsite review of the water source, facilities, equipment, operation and maintenance of a public water system for the purpose of evaluating the adequacy of such source, facilities, equipment, operation and maintenance for producing and distributing safe drinking water.

School, for the purpose of subpart I of this part only, means any building(s) associated with public, private, or charter institutions that primarily provides teaching and learning for elementary or secondary students.

Seasonal system is a non-community water system that is not operated as a public water system on a year-round basis and starts up and shuts down at the beginning and end of each operating season.

Secondary school, for the purpose of subpart I of this part only, 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.

Sedimentation means a process for removal of solids before filtration by gravity or separation.

Service connection, as used in the definition of public water system, does not include a connection to a system that delivers water by a constructed conveyance other than a pipe if:

(i) A non-community water system using only ground water (except ground water under the direct influence of surface water, as defined in § 141.2) and serving 1,000 persons or fewer must monitor each calendar quarter that the system provides water to the public, except that the State may reduce this monitoring frequency, in writing, if a sanitary survey shows that the system is free of sanitary defects. Beginning June 29, 1994, the State cannot reduce the monitoring frequency for a non-community water system using only ground water (except ground water under the direct influence of surface water, as defined in § 141.2) and serving 1,000 persons or fewer to less than once/year.

(1) Wholesale systems, as defined in § 141.2, must comply with the requirements of this subpart based on the population of the largest system in the combined distribution system.

(1) Systems receive Cryptosporidium treatment credit for membrane filtration that meets the criteria of this paragraph. Membrane cartridge filters that meet the definition of membrane filtration in § 141.2 are eligible for this credit. The level of treatment credit a system receives is equal to the lower of the values determined under paragraph (b)(1)(i) and (ii) of this section.

(i) The removal efficiency demonstrated during challenge testing conducted under the conditions in paragraph (b)(2) of this section.

(ii) The maximum removal efficiency that can be verified through direct integrity testing used with the membrane filtration process under the conditions in paragraph (b)(3) of this section.

(c) 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.

(1) The provisions of this subpart apply to community water systems and non-transient, non-community water systems (in this subpart referred to as “water systems” or “systems”) as defined at § 141.2.

As used in this subpart, the term:

(b) A system without corrosion control treatment is deemed to have OCCT as defined in § 141.2 if the system meets the requirement of either paragraph (b)(1) or (3) of this section. A system with corrosion control treatment is deemed to have OCCT as defined in § 141.2 or re-optimized OCCT if the system meets the requirements of either paragraphs (b)(1) and (4) or (b)(3) and (4) of this section. Systems must submit documentation of meeting the applicable requirements to the State in accordance with § 141.90(c)(1) by the applicable deadline for submitting tap sampling results under § 141.90(a)(2).

(1) A medium water system without corrosion control treatment or a small water system is deemed to have OCCT if the water system does not exceed the lead action level and copper action level during two consecutive six-month tap monitoring periods and then remains at or below the lead action level and copper action level in all tap sampling periods conducted in accordance with § 141.86.

(i) A small water system with corrosion control treatment is not eligible to be deemed to have OCCT pursuant to this paragraph (b)(1) where the State has set optimal water quality parameters (OWQPs) under paragraph (d) or (e) of this section.

(ii) If a medium water system without corrosion control treatment or a small water system deemed to have OCCT under this paragraph (b)(1) exceeds the lead action level or copper action level, the system must follow the requirements in paragraph (a) of this section.

(2) [Reserved]

(3) A water system is deemed to have optimized or re-optimized corrosion control treatment if it submits tap sampling results in accordance with § 141.86 demonstrating that the 90th percentile lead level is less than or equal to the lead practical quantitation limit of 0.005 mg/L for two consecutive six-month tap monitoring periods, it does not exceed the copper action level for two consecutive six-month tap monitoring periods, and it does not have OWQPs designated by the State under paragraph (d) or (e) of this section.

(i) A system with 90th percentile tap sampling results that later exceeds the lead practical quantitation limit of 0.005 mg/L or copper action level during any tap sampling period is not eligible to be deemed to have optimized OCCT in accordance with this paragraph (b)(3) until the system has completed the treatment steps specified in paragraph (d) or (e) of this section.

(ii) A system deemed to have OCCT in accordance with this paragraph (b)(3) must continue monitoring for lead and copper at the tap no less frequently than once every three calendar years using the reduced number of sites specified in § 141.86(d)(1) and collecting samples at times and locations specified in § 141.86(d)(2)(iii).

(4) A system with corrosion control treatment deemed to have OCCT under this paragraph (b) must continue to operate and maintain the corrosion control treatment and also meet any additional requirements that the State determines are appropriate to ensure OCCT is maintained.

(7) Based on the data and analysis for each treatment option evaluated under this paragraph (c), systems must recommend to the State, in writing, the treatment option that the corrosion control studies indicate constitutes OCCT for that system as defined in § 141.2. Systems must provide the State with a rationale for the OCCT recommendation and all supporting documentation specified in paragraph (c)(1) or (2) and paragraphs (c)(3) through (7) of this section.

(2) All water systems must develop an updated initial inventory, known as the “baseline inventory”. Systems must submit the baseline inventory to the State by the compliance date in § 141.80(a)(3). Newly regulated public water systems, as defined in § 141.2, must develop a baseline inventory on a schedule established by the State that does not exceed three years from the date the system becomes subject to National Primary Drinking Water Regulations in this part. The baseline inventory must include each service line and identified connector that is connected to the public water distribution system regardless of ownership status (e.g., where service line ownership is shared, the inventory includes both the portion of the service line owned by the water system and the portion of the service line owned by the customer).

(i) For the baseline inventory, water systems must conduct a review of any information listed in paragraphs (b)(2)(i) through (iii) of this section that describes connector materials and locations. Water systems must also conduct a review of any information on lead and galvanized iron or steel materials that they have identified pursuant to § 141.42(d) to identify connector materials and locations. The water system may use other sources of information not listed in paragraphs (b)(2)(i) through (iii) if approved or required by the State.

(ii) Water systems must include each connector identified in paragraph (a)(2)(i) of this section in their baseline inventory. Connector materials must be categorized in the following manner:

(A) “Lead” where the connector is made of lead.

(B) “Non-Lead” where the connector is determined through an evidence-based record, method, or technique not to be made of lead. Water systems are not required to identify the specific material of a non-lead connector; however, they may use the material (e.g., copper or galvanized) as an alternative to categorizing it as “Non-Lead”.

(C) “Unknown” where the material of the connector is not known.

(D) “No connector present” where there is no connector at the location (e.g., where a service line directly connects a water main to a building inlet).

(iii) All water systems must include any new information on service line materials from all applicable sources described in paragraph (b)(2) of this section in the baseline inventory.

(1) The provisions of this section apply to non-community water systems using only ground water (except ground water under the direct influence of surface water, as defined in § 141.2) and serving 1,000 or fewer people.

(1) The provisions of this section apply to community water systems using only ground water (except ground water under the direct influence of surface water, as defined in § 141.2) and serving 1,000 or fewer people.

(1) Except for samples described in paragraphs (b)(1)(iii) and (iv) of this section, all tap samples collected for analysis of lead and copper must be one liter in volume and have stood motionless in the plumbing system and/or service line of each sampling site for at least six hours. Bottles used to collect samples for analysis must be wide-mouth, one-liter sample bottles, as defined at § 141.2. Samples from residential housing must be collected from an interior kitchen or bathroom sink cold-water tap. Samples from a nonresidential building must be collected at an interior cold-water tap from which water is typically drawn for human consumption. Samples may be collected by the system, or the system may allow members of the public to collect samples after providing instructions for collecting samples in accordance with this paragraph (b)(1). Sample collection instructions cannot direct the sample collector to remove or clean the aerator or flush taps prior to the start of the minimum six-hour stagnation period. To protect members of the public from injury due to handling nitric acid, samples may be acidified up to 14 days after the sample is collected. After acidification to resolubilize the metals, the sample must stand in the original container for a period of time, as specified by the approved EPA method in § 141.23 selected for sample analysis. If a system allows members of the public to sample, the system cannot challenge the accuracy of the sampling results based on alleged sample collection errors.

(i) The first-liter sample must be analyzed for lead and copper at sample sites where both contaminants are required to be monitored. At sample sites where only lead is required to be monitored, the first-liter sample may be analyzed for only lead.

(ii) For sites served by a lead service line, which fall under Tier 1 and Tier 2, an additional fifth-liter sample must be collected at the same time as the first-liter sample and must be analyzed for lead. To collect a first-liter-and-fifth-liter-paired sample, systems must collect tap water in five consecutively numbered, wide-mouth, one-liter sample bottles after the water has stood motionless in the plumbing of each sampling site, including the lead service line, for at least six hours without flushing the tap prior to sample collection. Systems must collect samples starting with the first sample bottle and then fill each subsequently numbered bottle in consecutive order until the final bottle is filled, with the water running constantly while the samples are being collected. In this sequence, the first-liter sample is the first sample collected and the fifth-liter sample is the final sample collected.

(iii) State-approved samples collected pursuant to paragraph (b)(3) of this section may include samples with stagnation periods less than six hours, but must meet all the other sample collection criteria in this paragraph (b)(1), including being one-liter in volume using a wide-mouth bottle and collected at an interior tap from which water is typically drawn for human consumption.

(iv) Systems may use different sample volumes and/or different sample collection procedures when they collect follow-up samples for Distribution System and Site Assessment under § 141.82(j)(2) and consumer-requested samples under § 141.85(c) to assess the source of lead. Consumer-requested samples must be collected in accordance with § 141.85(c). Systems must submit these sample results to the State in accordance with § 141.90(a)(2)(i) and (g).

(i) A water system using only groundwater shall collect samples once during the three-year compliance period (as that term is defined in § 141.2) in effect when the applicable State determination under paragraph (d)(1) of this section is made. Such systems shall collect samples once during each subsequent compliance period. Triennial samples shall be collected every third calendar year.

(iv) If the school or child care facility maintains point-of-use devices as defined in § 141.2 on all outlets used to provide water for human consumption; or

(12) Section 141.92—reviewing lists of schools and child care facilities to ensure entries conform to the definitions of school and child care facility as defined in § 141.2 of this chapter and is complete.

As used in this part, and except as otherwise specifically provided:

(2) Does not have a Universal Product Code (UPC) assigned to the product;

(i) Which supplies any public water system as defined in § 141.2 of this chapter; or