§ 141.40 Monitoring requirements for unregulated contaminants.
(a) General applicability. This section specifies the monitoring and quality control requirements that must be followed if you own or operate a public water system (PWS) that is subject to the Unregulated Contaminant Monitoring Regulation (UCMR), as specified in paragraphs (a)(1) and (2) of this section. In addition, this section specifies the UCMR requirements for State and Tribal participation. For the purposes of this section, PWS “population served,” “State,” ” PWS Official,” “PWS Technical Contact,” and “finished water” apply as defined in § 141.35(a). The determination of whether a PWS is required to monitor under this rule is based on the type of system (e.g., community water system, non-transient non-community water system, etc.), and its retail population, as indicated by SDWIS/Fed on February 1, 2021 or subsequent corrections from the State.
(1) Applicability to transient non-community systems. If you own or operate a transient non-community water system, you are not subject to monitoring requirements in this section.
(2) Applicability to community water systems and non-transient non-community water systems—(i) Large systems. If you own or operate a retail PWS (other than a transient non-community system) that serves more than 10,000 people, you must monitor according to the specifications in this paragraph (a)(2)(i). If you believe that your applicability status is different than EPA has specified in the notification letter that you received, or if you are subject to UCMR requirements and you have not been notified by either EPA or your State, you must report to EPA, as specified in § 141.35(b)(2) or (c)(4).
(A) Assessment monitoring. You must monitor for the contaminants on List 1, per Table 1, UCMR Contaminant List, in paragraph (a)(3) of this section. If you serve a retail population of more than 10,000 people, you are required to perform this monitoring regardless of whether you have been notified by the State or EPA.
(B) Screening Survey. You must monitor for the unregulated contaminants on List 2 (Screening Survey) of Table 1, as specified in paragraph (a)(3) of this section, if your system serves 10,001 to 100,000 people and you are notified by EPA or your State that you are part of the State Monitoring Plan for Screening Survey testing. If your system serves more than 100,000 people, you are required to conduct this Screening Survey testing regardless of whether you have been notified by the State or EPA.
(C) Pre-Screen Testing. You must monitor for the unregulated contaminants on List 3 of Table 1, in paragraph (a)(3) of this section, if notified by your State or EPA that you are part of the Pre-Screen Testing.
(ii) Small systems. EPA will provide sample containers, provide pre-paid air bills for shipping the sampling materials, conduct the laboratory analysis, and report and review monitoring results for all small systems selected to conduct monitoring under paragraphs (a)(2)(ii)(A) through (C) of this section. If you own or operate a PWS (other than a transient non-community water system) that serves a retail population of 10,000 or fewer people and you are notified of monitoring requirements by the State or EPA, you must monitor as follows:
(A) Assessment Monitoring. You must monitor for the contaminants on List 1 per table 1 to paragraph (a)(3) if you are notified by your State or EPA that you are part of the State Monitoring Plan for Assessment Monitoring.
(B) Screening Survey. You must monitor for the unregulated contaminants on List 2 of Table 1, in paragraph (a)(3) of this section, if notified by your State or EPA that you are part of the State Monitoring Plan for the Screening Survey.
(C) Pre-screen testing. You must monitor for the contaminants on List 3 of Table 1, in paragraph (a)(3) of this section if you are notified by your State or EPA that you are part of the State Monitoring Plan for Pre-Screen Testing.
(3) Analytes to be monitored. Lists 1, 2, and 3 contaminants are provided in table 1 to paragraph (a)(3):
Table 1 to Paragraph (a)(3)—UCMR Contaminant List
| 1—Contaminant | 2—CASRN | 3—Analytical methods a | 4—Minimum reporting level b | 5—Sampling location c | 6—Period during which sample collection to be completed |
|---|---|---|---|---|---|
| List 1: Assessment Monitoring | |||||
| Per- and Polyfluoroalkyl Substances (PFAS) | |||||
| 11-chloroeicosafluoro-3-oxaundecane-1-sulfonic acid (11Cl-PF3OUdS) | 763051–92–9 | EPA 533 | 0.005 µg/L | EPTDS | 1/1/2023–12/31/2025 |
| 1H, 1H, 2H, 2H-perfluorodecane sulfonic acid (8:2 FTS) | 39108–34–4 | EPA 533 | 0.005 µg/L | EPTDS | 1/1/2023–12/31/2025 |
| 1H, 1H, 2H, 2H-perfluorohexane sulfonic acid (4:2 FTS) | 757124–72–4 | EPA 533 | 0.003 µg/L | EPTDS | 1/1/2023–12/31/2025 |
| 1H, 1H, 2H, 2H-perfluorooctane sulfonic acid (6:2 FTS) | 27619–97–2 | EPA 533 | 0.005 µg/L | EPTDS | 1/1/2023–12/31/2025 |
| 4,8-dioxa-3H-perfluorononanoic acid (ADONA) | 919005–14–4 | EPA 533 | 0.003 µg/L | EPTDS | 1/1/2023–12/31/2025 |
| 9-chlorohexadecafluoro-3-oxanone-1-sulfonic acid (9Cl-PF3ONS) | 756426–58–1 | EPA 533 | 0.002 µg/L | EPTDS | 1/1/2023–12/31/2025 |
| hexafluoropropylene oxide dimer acid (HFPO-DA) (GenX) | 13252–13–6 | EPA 533 | 0.005 µg/L | EPTDS | 1/1/2023–12/31/2025 |
| nonafluoro-3,6-dioxaheptanoic acid (NFDHA) | 151772–58–6 | EPA 533 | 0.02 µg/L | EPTDS | 1/1/2023–12/31/2025 |
| perfluoro (2-ethoxyethane) sulfonic acid (PFEESA) | 113507–82–7 | EPA 533 | 0.003 µg/L | EPTDS | 1/1/2023–12/31/2025 |
| perfluoro-3-methoxypropanoic acid (PFMPA) | 377–73–1 | EPA 533 | 0.004 µg/L | EPTDS | 1/1/2023–12/31/2025 |
| perfluoro-4-methoxybutanoic acid (PFMBA) | 863090–89–5 | EPA 533 | 0.003 µg/L | EPTDS | 1/1/2023–12/31/2025 |
| perfluorobutanesulfonic acid (PFBS) | 375–73–5 | EPA 533 | 0.003 µg/L | EPTDS | 1/1/2023–12/31/2025 |
| perfluorobutanoic acid (PFBA) | 375–22–4 | EPA 533 | 0.005 µg/L | EPTDS | 1/1/2023–12/31/2025 |
| perfluorodecanoic acid (PFDA) | 335–76–2 | EPA 533 | 0.003 µg/L | EPTDS | 1/1/2023–12/31/2025 |
| perfluorododecanoic acid (PFDoA) | 307–55–1 | EPA 533 | 0.003 µg/L | EPTDS | 1/1/2023–12/31/2025 |
| perfluoroheptanesulfonic acid (PFHpS) | 375–92–8 | EPA 533 | 0.003 µg/L | EPTDS | 1/1/2023–12/31/2025 |
| perfluoroheptanoic acid (PFHpA) | 375–85–9 | EPA 533 | 0.003 µg/L | EPTDS | 1/1/2023–12/31/2025 |
| perfluorohexanesulfonic acid (PFHxS) | 355–46–4 | EPA 533 | 0.003 µg/L | EPTDS | 1/1/2023–12/31/2025 |
| perfluorohexanoic acid (PFHxA) | 307–24–4 | EPA 533 | 0.003 µg/L | EPTDS | 1/1/2023–12/31/2025 |
| perfluorononanoic acid (PFNA) | 375–95–1 | EPA 533 | 0.004 µg/L | EPTDS | 1/1/2023–12/31/2025 |
| perfluorooctanesulfonic acid (PFOS) | 1763–23–1 | EPA 533 | 0.004 µg/L | EPTDS | 1/1/2023–12/31/2025 |
| perfluorooctanoic acid (PFOA) | 335–67–1 | EPA 533 | 0.004 µg/L | EPTDS | 1/1/2023–12/31/2025 |
| perfluoropentanesulfonic acid (PFPeS) | 2706–91–4 | EPA 533 | 0.004 µg/L | EPTDS | 1/1/2023–12/31/2025 |
| perfluoropentanoic acid (PFPeA) | 2706–90–3 | EPA 533 | 0.003 µg/L | EPTDS | 1/1/2023–12/31/2025 |
| perfluoroundecanoic acid (PFUnA) | 2058–94–8 | EPA 533 | 0.002 µg/L | EPTDS | 1/1/2023–12/31/2025 |
| n-ethyl perfluorooctanesulfonamidoacetic acid (NEtFOSAA) | 2991–50–6 | EPA 537.1 | 0.005 µg/L | EPTDS | 1/1/2023–12/31/2025 |
| n-methyl perfluorooctanesulfonamidoacetic acid (NMeFOSAA) | 2355–31–9 | EPA 537.1 | 0.006 µg/L | EPTDS | 1/1/2023–12/31/2025 |
| perfluorotetradecanoic acid (PFTA) | 376–06–7 | EPA 537.1 | 0.008 µg/L | EPTDS | 1/1/2023–12/31/2025 |
| perfluorotridecanoic acid (PFTrDA) | 72629–94–8 | EPA 537.1 | 0.007 µg/L | EPTDS | 1/1/2023–12/31/2025 |
| Metal/Pharmaceutical | |||||
| Lithium | 7439–93–2 | EPA 200.7, SM 3120 B, ASTM D1976–20 | 9 µg/L | EPTDS | 1/1/2023–12/31/2025 |
| List 2: Screening Survey | |||||
| Reserved | Reserved | Reserved | Reserved | Reserved | Reserved |
| List 3: Pre-Screen Testing | |||||
| Reserved | Reserved | Reserved | Reserved | Reserved | Reserved |