vvEPA
The Fifth Unregulated Contaminant Monitoring Rule (UCMR 5)
Data Summary: July 2023
Overview
EPA has released the first set of data collected under the Fifth Unregulated Contaminant Monitoring Rule
(UCMR 5) for the 30 chemical contaminants (29 per- and polyfluoroalkyl substances [PFAS] and lithium) listed in
Table 1. This initial data release represents approximately 7% of the total results that EPA expects to receive
over the next three years. The Agency will update the results quarterly in EPA's National Contaminant
Occurrence Database (NCOD) until completion of data reporting in 2026. Data are added and possibly removed
or updated over the course of this reporting cycle following further review by analytical laboratories, public
water systems (PWSs), states, and EPA. Before conducting your own assessment of the data, please review the
Data Considerations section. For answers to common questions regarding accessing and understanding the
UCMR 5 data, as well as information on PFAS and lithium in drinking water, please review the UCMR 5 website.
UCMR 5 will provide new data that will improve EPA's understanding of the frequency these contaminants are
found in the nation's drinking water systems, and at what levels. The monitoring data on PFAS and lithium will
help the Agency make determinations about future regulations and other actions to protect public health under
the Safe Drinking Water Act (SDWA). This monitoring also helps federal, state, and other researchers prioritize
studies for health effects information, identify data gaps, and determine the need for future studies to improve
our understanding of the possible health risks associated with these contaminants in public drinking water.
Through the Bipartisan Infrastructure Law. EPA is helping states, Tribes, and especially small, disadvantaged, and
rural communities to leverage billions of dollars in funding dedicated to investments in infrastructure solutions.
Those investments will allow communities to remove emerging contaminants, like PFAS and lithium, from their
drinking water. For more information, visit EPA's website.
Based on this limited initial set of data, we note the following:
• PFOA and PFOS are two of the most widely studied PFAS. One or each of these two PFAS was measured
at or above EPA's minimum reporting level (MRL), and therefore above EPA's Health Advisory (HA)
levels, in the first sampling event for 7.8-8.5% of PWSs with results to date.
• The other two PFAS with EPA HA levels are HFPO-DA ("GenX chemicals") and PFBS. HFPO-DA was
measured above its HA level by 1 of 2,002 PWSs. PFBS was not found above its HA level.
• HA levels have not been established for the other 25 PFAS that are part of UCMR 5.
o Nine of these 25 PFAS were measured at or above their respective MRL by 1-207 of
approximately 2,000 PWSs.
o For the other 16 PFAS, no PWSs have reported results at or above their respective MRLs.
• EPA has not published a HA level for lithium but has calculated a Health Reference Level (HRL) for
screening purposes. To date, 22% of PWSs have reported lithium results above the screening HRL.
Additional details on contaminant health effects information and a summary of occurrence results to date may
be found in Table 2 and Table 3. respectively.
July 2023
Office of Water (MS-140)
EPA 815-S-23-003
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Background
EPA uses the UCMR program to collect nationally representative data for contaminants that may be present in
drinking water but are not yet subject to regulatory standards set under SDWA. This monitoring is used by EPA
to understand the frequency and level of occurrence of unregulated contaminants in the nation's PWSs. Every
five years, taking into consideration EPA's Contaminant Candidate List (CCL), the Agency develops a new list of
UCMR contaminants for monitoring. SDWA, as amended by Section 2021 of America's Water Infrastructure Act
of 2018, calls for EPA to:
• Issue a list of unregulated contaminants to be monitored by certain PWS types1 every five years
• Require large PWSs (i.e., those that serve more than 10,000 people) to monitor the contaminants
• Require small PWSs serving between 3,300 and 10,000 people to monitor, subject to the availability of
EPA appropriations and sufficient laboratory capacity
• Require a nationally representative sample of small PWSs serving less than 3,300 people to monitor
• Make analytical results available in NCOD
State and local officials may also use UCMR data to assess the need for actions to protect public health. When
evaluating UCMR data, one should consider the following:
• UCMR monitoring generates a robust dataset that is representative of national occurrence.
• UCMR results are available after PWSs and the laboratories that support their monitoring have
reported results to EPA (up to four months after the samples are collected). Small PWS results may be
available sooner relative to large PWS results since the laboratories contracted by EPA to analyze small
PWS samples are contractually obligated to report results within a shorter timeframe.
• There is information about health effects and treatment techniques to address some of these
unregulated contaminants.
1 UCMR 5 requirements apply to community water systems (CWSs) and non-transient non-community water systems (NTNCWSs). They
do not apply to transient non-community water systems (TNCWSs). The use of "PWS" throughout this document refers to participating
CWSs and NTNCWSs. For more information on PWS types, visit EPA's website.
July 2023
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Table 1. Contaminants and Methods
Contaminant
CASRN1
EPA
Method
Contaminant
Classification
lithium
7439-93-2
200.7
Metal/Pharmaceutical
hexafluoropropylene oxide dimer acid (HFPO-DA) (GenX
chemicals)
13252-13-6
533
PFAS
perfluorobutanesulfonic acid (PFBS)
375-73-5
533
PFAS
perfluorooctanesulfonic acid (PFOS)
1763-23-1
533
PFAS
perfluorooctanoic acid (PFOA)
335-67-1
533
PFAS
perfluorohexanesulfonic acid (PFHxS)
355-46-4
533
PFAS
perfluorononanoic acid (PFNA)
375-95-1
533
PFAS
perfluorobutanoic acid (PFBA)
375-22-4
533
PFAS
perfluorohexanoic acid (PFHxA)
307-24-4
533
PFAS
perfluorodecanoic acid (PFDA)
335-76-2
533
PFAS
ll-chloroeicosafluoro-3-oxaundecane-l-sulfonic acid
(HCI-PF30UdS)
763051-92-9
533
PFAS
1H, 1H, 2H, 2H-perfluorodecane sulfonic acid (8:2 FTS)
39108-34-4
533
PFAS
1H, 1H, 2H, 2H-perfluorohexane sulfonic acid (4:2 FTS)
757124-72-4
533
PFAS
1H, 1H, 2H, 2H-perfluorooctane sulfonic acid (6:2 FTS)
27619-97-2
533
PFAS
4,8-dioxa-3H-perfluorononanoic acid (ADONA)
919005-14-4
533
PFAS
9-chlorohexadecafluoro-3-oxanone-l-sulfonic acid (9CI-
PF30NS)
756426-58-1
533
PFAS
nonafluoro-3,6-dioxaheptanoic acid (NFDHA)
151772-58-6
533
PFAS
perfluoro (2-ethoxyethane) sulfonic acid (PFEESA)
113507-82-7
533
PFAS
perfluoro-3-methoxypropanoic acid (PFMPA)
377-73-1
533
PFAS
perfluoro-4-methoxybutanoic acid (PFMBA)
863090-89-5
533
PFAS
perfluorododecanoic acid (PFDoA)
307-55-1
533
PFAS
perfluoroheptanesulfonic acid (PFHpS)
375-92-8
533
PFAS
perfluoroheptanoic acid (PFHpA)
375-85-9
533
PFAS
perfluoropentanesulfonic acid (PFPeS)
2706-91-4
533
PFAS
perfluoropentanoic acid (PFPeA)
2706-90-3
533
PFAS
perfluoroundecanoic acid (PFUnA)
2058-94-8
533
PFAS
n-ethyl perfluorooctanesulfonamidoacetic acid
(NEtFOSAA)
2991-50-6
537.1
PFAS
n-methyl perfluorooctanesulfonamidoacetic acid
(NMeFOSAA)
2355-31-9
537.1
PFAS
perfluorotetradecanoic acid (PFTA)
376-06-7
537.1
PFAS
perfluorotridecanoic acid (PFTrDA)
72629-94-8
537.1
PFAS
1 CASRN - Chemical Abstracts Service Registry Number
July 2023
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Information About UCMR 5 Results
The purpose of this document is to (1) summarize UCMR 5 results reported to date and (2) provide context
around UCMR 5 results in relation to EPA established minimum reporting levels (MRLs) and, if available, health-
based reference values (i.e., reference concentrations and reference doses [RfDs]). The UCMR 5 MRLs are the
lowest concentrations that laboratories may report to EPA during UCMR 5 monitoring. UCMR MRLs are
determined using data from multiple laboratories that participate in EPA's MRL-setting studies and are not
associated with contaminant health effects information. EPA establishes MRLs to ensure consistency in the
quality of the information reported to the Agency.
Depending on the available health and toxicological information for a UCMR 5 contaminant, a reference
concentration (e.g., a lifetime Health Advisory [HA] level, Health Reference Level [HRL]) in drinking water may be
available. Reference concentrations can be derived from an RfD (i.e., a non-cancer endpoint) or an oral cancer
slope factor (CSF) (i.e., a cancer endpoint), if available, and consider additional assumptions about body weight
and drinking water intake. The health-based reference values identified in this document do not represent
regulatory limits or action levels and should not be interpreted as an indication of future Agency actions. UCMR
occurrence data are used to inform the Agency's Regulatory Determination process (i.e., the process that
addresses potential regulatory actions for unregulated contaminants).
Community water systems (CWSs) required to monitor under UCMR must inform their customers of UCMR
results (including the average and range of results) in their annual Consumer Confidence Report (CCR). See 40
CFR 141.153(d)(7) for the CCR regulatory requirements and Section IV of EPA's guidance Preparing Your Drinking
Water Consumer Confidence Report for details on the content of the report. Additional resources are available
on EPA's CCR Compliance Help web page.
Non-transient non-community water systems (NTNCWSs), such as an office park or school that operates its own
water system, and CWSs required to monitor under UCMR must inform their customers of the availability of all
UCMR results through Tier 3 Public Notification (PN). See 40 CFR 141.207 for the PN regulatory requirements
and EPA's PN Compliance Help web page for guidance.
EPA recognizes the high interest in timely access to UCMR results and is committed to publicly posting results on
the Agency's web page approximately quarterly (following large PWS review of their UCMR results and EPA
review of small PWS results). EPA manages the laboratory analyses for small PWSs and will work to
communicate their results in a timely manner. Large PWSs wishing to have earlier access to their data should
consider making arrangements with their UCMR 5 laboratory for early notification of particular UCMR results
(i.e., before their contracted laboratory posts the results to the UCMR web-based reporting system).
States may establish requirements (regulatory or non-regulatory) for drinking water contaminants not yet
regulated by EPA, and those requirements may be based on state-established levels that differ from EPA's
reference concentrations. PWSs are responsible for being aware of and complying with their state's
requirements, if any.
On March 14, 2023, EPA announced a proposed National Primary Drinking Water Regulation (NPDWR) for six
PFAS included in UCMR 5 monitoring. The proposed PFAS NPDWR does not require any actions until it is
finalized. EPA's PFAS website provides additional information on Agency actions to address PFAS contamination,
describes current PFAS research, and identifies related tools and resources.
Available drinking water treatment information for UCMR 5 contaminants can be found in EPA's Drinking Water
Treatability Database.
July 2023
Office of Water (MS-140)
EPA 815-S-23-003
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Health-Based Reference Values
Table 2 provides health-based reference values (i.e., reference concentrations and RfDs) for each contaminant
monitored under UCMR 5, if available. To identify reference values, EPA applied the following principles:
(1) Reference concentrations and RfDs were compiled from the following publicly available resources:
a. Drinking Water Health Advisories (HAs).
b. Integrated Risk Information System (IRIS) Assessments.
c. Technical Support Document for the Final CCL 5 - Contaminant Information Sheets, and
d. Agency for Toxic Substances and Disease Registry (ATSDR) Toxicological Profiles
The above resources are the products (or compilation) of peer-reviewed health assessments. The
reference values are subject to change as new health assessments are completed; they are not legally
enforceable federal standards.
(2) If health information was available from more than one of the resources listed above, the most recent
health information was used.
(3) If both cancer and non-cancer reference concentrations were available from the most recent resource,
the lower (more conservative) of the two concentrations was used. Please review references and
footnotes in Table 2 for additional health effects information.
(4) If an RfD (i.e., a non-cancer endpoint) was the basis for the reference concentration, and both chronic
and subchronic/short-term exposure values were available from the most recent resource, the lower
concentration (associated with the chronic exposure) was used. Please review references and footnotes
in Table 2 for additional health effects information (e.g., additional short-term, subchronic, or chronic
values).
(5) For the contaminants that do not have a reference concentration available from a resource listed above,
only the RfDs from finalized health assessments are provided in Table 2. if available. If a health
assessment is in process, a link to additional information about its status is provided.
EPA considers this a "living document" and will update Table 2 as new health-based information becomes
available. For example, the Agency is currently using the 2022 EPA lifetime HA levels for GenX chemicals, PFBS,
PFOS, and PFOA as reference concentrations for UCMR 5 and will update the values, as appropriate, when the
final PFAS NPDWR is promulgated.
July 2023
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EPA 815-S-23-003
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Table 2. Minimum Reporting Levels (MRLs) and Health-Based Reference Values
Contaminant
[note: to convert to ng/L or parts per trillion
(ppt), multiply by 1,000]
MRL
(Hg/L)
Health-Based Reference Values
Reference
Concentration „ , .
tw/lj (mg/kg-day)
Reference(s)
lithium1
9
HRL = 10
Subchronic and Chronic
Provisional RfD = 2 x 10"3
Technical Support Document for the Final CCL 5
- Contaminant Information Sheets (2022)
hexafluoropropylene oxide dimer acid (HFPO-
DA) (GenX chemicals)2,3
0.005
Lifetime HA =
0.01
Chronic RfD = 3 x 10"6
Drinking Water Health Advisorv:
Hexafluoropropvlene Oxide (HFPO) Dimer Acid
and HFPO Dimer Acid Ammonium Salt, Also
Known as "GenX Chemicals" (2022)
perfluorobutanesulfonic acid (PFBS)2,3
0.003
Lifetime HA = 2
Chronic RfD = 3 x 10"4
Drinking Water Health Advisorv: Perfluorobutane
Sulfonic Acid and Related Compound Potassium
Perfluorobutane Sulfonate (2022)
perfluorooctanesulfonic acid (PFOS)3,4
0.004
Lifetime Interim
HA = 0.00002
Chronic RfD = 7.9 x 10"9
INTERIM Drinking Water Health Advisorv:
Perfluorooctane Sulfonic Acid (PFOS) (2022)
perfluorooctanoic acid (PFOA)3,4
0.004
Lifetime Interim
HA = 0.000004
Chronic RfD = 1.5 x 10"9
INTERIM Drinking Water Health Advisorv:
Perfluorooctanoic Acid (PFOA) (2022)
perfluorohexanesulfonic acid (PFHxS)3,5
0.003
ATSDR: Minimal Risk
Level = 2 x 10"5
(intermediate duration)
ATSDR Toxicological Profile for Perfluoroalkvls
(2021)
perfluorononanoic acid (PFNA)3,5
0.004
ATSDR: Minimal Risk
Level = 3 x 10"6
(intermediate duration)
ATSDR Toxicological Profile for Perfluoroalkvls
(2021)
perfluorobutanoic acid (PFBA)
0.005
-
Chronic RfD = 1 x 10"3
Subchronic RfD = 6 x 10"3
Integrated Risk Information Svstem (IRIS)
Assessment (2022)
perfluorohexanoic acid (PFHxA)
0.003
-
Subchronic and Chronic
RfD = 5 x 10"4
Integrated Risk Information Svstem (IRIS)
Assessment (2023)
1 The reference concentration is the Health Reference Level (HRL) calculated as part of the CCL 5 process and is based on the RfD from the following health assessment:
Provisional Peer-Reviewed Toxicity Values (PPRTV). 2008.
2 More information is available on the final lifetime HAs for GenX chemicals and PFBS.
3 On March 14, 2023, EPA announced a proposed NPDWR for six PFAS (GenX chemicals, PFBS, PFOS, PFOA, PFHxS, and PFNA). After EPA has considered public comments and
publishes a final PFAS NPDWR, EPA will update the reference concentrations for these six PFAS as appropriate.
4 More information is available on the interim lifetime HAs for PFOA and PFOS.
5 In process/draft EPA Integrated Risk Information System (IRIS) assessments for PFHxS and PFNA.
July 2023
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EPA 815-S-23-003
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Contaminant
[note: to convert to ng/L or parts per trillion
(ppt), multiply by 1,000]
MRL
(Hg/L)
Health-Based Reference Values
Reference __
RfD
Concentration „ , .
tw/lj (mg/kg-day)
Reference(s)
perfluorodecanoic acid (PFDA)
0.003
"
"
IN PROCESS/DRAFT Integrated Risk Information
Svstem (IRIS) Assessment
ll-chloroeicosafluoro-3-oxaundecane-l-
sulfonicacid (HCI-PF30udS)
0.005
"
"
-
1H, 1H, 2H, 2H-perfluorodecane sulfonic acid
(8:2 FTS)
0.005
"
"
-
1H, 1H, 2H, 2H-perfluorohexane sulfonic acid
(4:2 FTS)
0.003
"
"
-
1H, 1H, 2H, 2H-perfluorooctane sulfonic acid
(6:2 FTS)
0.005
"
"
-
4,8-dioxa-3H-perfluorononanoic acid (ADONA)
0.003
-
-
-
9-chlorohexadecafluoro-3-oxanone-l-sulfonic
acid (9CI-PF30NS)
0.002
"
"
-
nonafluoro-3,6-dioxaheptanoic acid (NFDHA)
0.02
-
-
-
perfluoro (2-ethoxyethane) sulfonic acid
(PFEESA)
0.003
"
"
-
perfluoro-3-methoxypropanoic acid (PFMPA)
0.004
-
-
-
perfluoro-4-methoxybutanoic acid (PFMBA)
0.003
-
-
-
perfluorododecanoic acid (PFDoA)
0.003
-
-
-
perfluoroheptanesulfonic acid (PFHpS)
0.003
-
-
-
perfluoroheptanoic acid (PFHpA)
0.003
-
-
-
perfluoropentanesulfonic acid (PFPeS)
0.004
-
-
-
perfluoropentanoic acid (PFPeA)
0.003
-
-
-
perfluoroundecanoic acid (PFUnA)
0.002
-
-
-
n-ethyl perfluorooctanesulfonamidoacetic acid
(NEtFOSAA)
0.005
"
"
-
n-methyl perfluorooctanesulfonamidoacetic
acid (NMeFOSAA)
0.006
"
"
-
perfluorotetradecanoic acid (PFTA)
0.008
-
-
-
perfluorotridecanoic acid (PFTrDA)
0.007
-
-
-
July 2023
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EPA 815-S-23-003
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Terms and Definitions
a) MRL- UCMR Minimum Reporting Level. The lowest concentration that laboratories may report to EPA during UCMR 5
monitoring. MRLs are not associated with health effects information. More specifically, an MRL is the quantitation limit
for a contaminant that is considered achievable, with 95% confidence, by at least 75% of laboratories nationwide using
a specified analytical method (recognizing that individual laboratories may be able to measure at lower levels). [Note
that the Agency for Toxic Substances and Disease Registry (ATSDR) uses the term "MRL" for a different purpose [i.e.,
to describe "Minimal Risk Level"). The UCMR term and the ATSDR term have no relationship to each other.]
b) Ref Cone - Reference Concentration. Published EPA Drinking Water Health Advisories (HAs) and the Health Reference
Levels (HRLs) from EPA's Fifth Contaminant Candidate List (CCL 5). These reference concentrations are derived from
peer-reviewed health assessments published by EPA or other governmental agencies. They are not legally enforceable
federal standards and are subject to change as new health assessments are completed. Depending on available health
effects information, a reference concentration in drinking water can be derived from a reference dose (RfD) (i.e., a non-
cancer endpoint) or a cancer slope factor (CSF) (i.e., a cancer endpoint), and considers additional assumptions about
body weight and drinking water intake.
c) HA - Health Advisory. Provides information on a contaminant that can cause negative human health effects and is
known or anticipated to occur in drinking water. SDWA authorizes EPA to issue HAs for contaminants that are not
subject to a National Primary Drinking Water Regulation (NPDWR). EPA's HAs are non-enforceable and non-regulatory
and provide technical information to state agencies and other public health officials on health effects, analytical
methods, and treatment technologies associated with drinking water contaminants. The HA documents include the
derivation of the HA levels, which are the concentrations of contaminants at or below which adverse health effects are
not anticipated to occur over specific exposure durations, such as one day, 10 days, or a lifetime. The lifetime HA for
the drinking water contaminant is calculated from its associated Drinking Water Equivalent Level (DWEL), obtained
from its RfD, and incorporates a drinking water Relative Source Contribution (RSC) factor of contaminant-specific data
or a default of 20% of total exposure from all sources. For more information, visit EPA's Drinking Water HAs web page.
Answers to frequently asked questions on EPA's lifetime HAs for PFAS are also available.
d) HRL- Health Reference Level. Derived during the CCL 5 process for screening purposes. HRLs are used in EPA's
Regulatory Determination process as risk-derived concentrations against which to evaluate the occurrence data to
determine if contaminants occur at levels of public health concern. To determine the HRL for a chemical, EPA
considered adverse health effects that may pose a greater risk to specific life stages and other sensitive groups which
represent a meaningful portion of the population. HRLs are not final determinations about the level of a contaminant
in drinking water that is necessary to protect any particular population and, in some cases, are derived prior to
development of a complete exposure assessment using the best available data. HRLs are not legally enforceable federal
standards. For more information on HRL derivation, please see the Technical Support Document for the Final CCL 5
(tint.)min.)nt Information Sheets.
e) RfD - Oral Reference Dose. A non-cancer estimate (with uncertainty spanning perhaps an order of magnitude) of a
daily oral exposure to the human population (including sensitive subgroups) that is likely to be without an appreciable
risk of deleterious effects during a lifetime. It is typically derived by dividing a point-of-departure (POD) from a selected
dose-response study (e.g., no-observed-adverse-effect level [NOAEL], lowest-observed-adverse-effect level [LOAEL],
benchmark dose [BMD]) by the uncertainty factors (UFs) applied to reflect database limitations. Chronic RfDs are
typically derived from animal toxicological studies with an exposure duration of months to years, representing a
lifetime exposure in humans. Subchronic RfDs are typically derived from animal toxicological studies with an exposure
duration of 31 to 90 days, representing a less than lifetime exposure in humans (up to 10% of average lifespan). Visit
EPA's IRIS website for more information about RfD derivation.
f) Minimal Risk Levels - Developed by ATSDR as screening tools to help identify chemicals that may be of concern. A
minimal risk level is an estimate of the daily human exposure to a hazardous substance that is likely to be without
appreciable risk of adverse non-cancer health effects over a specified route and duration of exposure. Minimal risk
levels are derived when reliable and sufficient data exist to identify the target organ(s) of effect or the most sensitive
health effect(s) for a specific duration for a given route of exposure. These substance specific estimates, which are
intended to serve as screening levels, are used by ATSDR health assessors to determine areas and populations
potentially at risk for health effects from exposure to a particular substance. Exposure above the minimal risk level
does not mean that health problems will occur. Instead, it may act as a signal to health assessors to look more closely
at a particular site where exposures may be identified. Minimal risk levels do not define regulatory or action levels for
ATSDR.
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Table 3. July 2023 Data Summary1
Contaminant
MRL2
(Hg/L)
Ref Cone3
(Hg/L)
Total
number
of
results
Number
of
results
>MRL
Number of
results
>Ref Cone4
% of total
results
>Ref Cone4
Total
number of
PWSs with
results
Number of
PWSs with
results
>MRL
Number of
PWSs with
results
>Ref Cone4
% of PWSs
with
results
>Ref Cone4
lithium
9
10
5,365
1,579 1,132
21.1%
2,236
681
494
22.1%
hexafluoropropylene oxide dimer acid
(HFPO-DA) (GenX chemicals)
0.005
0.01
4,668
6
1
0.02%
2,002
6
1
0.05%
perfluorobutanesulfonic acid (PFBS)
0.003
2
4,667
316
0
0.0%
2,003
192
0
0.0%
perfluorooctanesulfonic acid (PFOS)5
0.004
0.00002
4,665
279
279
6.0%
2,001
170
170
8.5%
perfluorooctanoic acid (PFOA)5
0.004
0.000004
4,667
267
267
5.7%
2,002
156
156
7.8%
perfluorohexanesulfonic acid (PFHxS)
0.003
-
4,666
219
-
-
2,001
123
-
"
perfluorononanoic acid (PFNA)
0.004
-
4,668
14
-
-
2,002
9
-
-
perfluorobutanoic acid (PFBA)
0.005
-
4,667
313
-
-
2,002
198
-
-
perfluorohexanoic acid (PFHxA)
0.003
-
4,668
322
-
-
2,002
198
-
-
perfluorodecanoic acid (PFDA)
0.003
-
4,669
2
-
-
2,002
1
-
-
ll-chloroeicosafluoro-3-oxaundecane-
1-sulfonic acid (HCI-PF30UdS)
0.005
-
4,669
0
-
-
2,002
0
-
-
1H, 1H, 2H, 2H-perfluorodecane
sulfonic acid (8:2 FTS)
0.005
-
4,669
0
-
-
2,002
0
-
"
1H, 1H, 2H, 2H-perfluorohexane
sulfonic acid (4:2 FTS)
0.003
-
4,669
0
-
-
2,002
0
-
"
1H, 1H, 2H, 2H-perfluorooctane
sulfonic acid (6:2 FTS)
0.005
-
4,669
23
2,002
14
"
1 This data summary represents approximately 7% of total results that EPA expects to receive over the next three years. Analytical results from the UCMR program are reported
by laboratories and provided by EPA in micrograms/liter (|ag/L, parts per billion). To convert results in pg/L to nanograms/liter (ng/L, parts per trillion), multiply the value by
1,000. UCMR results do not represent locational running annual averages.
2 MRL- EPA established Minimum Reporting Level. Based on laboratory capability; not related to contaminant health effects information.
3 Ref Cone - Reference Concentration. EPA Health Advisories (HAs) for four PFAS and EPA's CCL 5 Health Reference Level (HRL) for lithium.
4 EPA HAs and HRLs are expressed with one significant digit; comparison of UCMR results to HAs and HRLs is therefore based on one significant digit. Results >0.015 |ag/L for
GenX chemicals and >2.5 ng/L for PFBS round to >0.02 ng/L and >3 ng/L, respectively, and are identified as above reference concentrations. Results for lithium are likewise
identified as above the reference concentration if they are >15 ng/L.
5 The HA levels for PFOA and PFOS are below the levels that can be reliably measured; thus, the UCMR 5 MRLs for PFOA and PFOS are greater than the HA levels. Any result at or
above the MRL for PFOA or PFOS is understood to be above its HA level. The number and % of PWSs with results above the reference concentration for PFOA and/or PFOS is
greater than or equal to the number and % of PWSs with results at or above the UCMR 5 MRL.
July 2023
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EPA 815-S-23-003
Page 9 of 13
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Contaminant
MRL2
(Hg/L)
Ref Cone3
(Hg/L)
Total
number
of
results
Number
of
results
>MRL
Number of
results
>Ref Cone4
% of total
results
>Ref Cone4
Total
number of
PWSs with
results
Number of
PWSs with
results
>MRL
Number of
PWSs with
results
>Ref Cone4
% of PWSs
with
results
>Ref Cone4
4,8-dioxa-3H-perfluorononanoic acid
(ADONA)
0.003
-
4,669
0
-
-
2,002
0
-
-
9-chlorohexadecafluoro-3-oxanone-l-
sulfonic acid (9CI-PF30NS)
0.002
-
4,669
0
-
-
2,002
0
-
-
nonafluoro-3,6-dioxaheptanoic acid
(NFDHA)
0.02
-
4,641
0
-
-
1,989
0
-
-
perfluoro (2-ethoxyethane) sulfonic
acid (PFEESA)
0.003
-
4,669
0
-
-
2,002
0
-
-
perfluoro-3-methoxypropanoic acid
(PFMPA)
0.004
-
4,669
0
-
-
2,002
0
-
-
perfluoro-4-methoxybutanoic acid
(PFMBA)
0.003
-
4,669
0
-
-
2,002
0
-
-
perfluorododecanoic acid (PFDoA)
0.003
-
4,669
0
-
-
2,002
0
-
-
perfluoroheptanesulfonic acid (PFHpS)
0.003
-
4,668
0
-
-
2,002
0
-
-
perfluoroheptanoic acid (PFHpA)
0.003
-
4,669
118
-
-
2,002
72
-
-
perfluoropentanesulfonic acid (PFPeS)
0.004
-
4,670
5
-
-
2,002
5
-
-
perfluoropentanoic acid (PFPeA)
0.003
-
4,668
356
-
-
2,002
207
-
-
perfluoroundecanoic acid (PFUnA)
0.002
-
4,643
0
-
-
1,989
0
-
-
n-ethyl
perfluorooctanesulfonamidoacetic acid
(NEtFOSAA)
0.005
4,596
0
1,854
0
n-methyl
perfluorooctanesulfonamidoacetic acid
(NMeFOSAA)
0.006
4,596
0
1,854
0
perfluorotetradecanoic acid (PFTA)
0.008
-
4,596
0
-
-
1,854
0
-
-
perfluorotridecanoic acid (PFTrDA)
0.007
-
4,596
0
-
-
1,854
0
-
-
July 2023
Office of Water (MS-140)
EPA 815-S-23-003
Page 10 of 13
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Data Considerations
Data are presented as tab delimited text files within zip files (see below for descriptions), with field names included in the
first row of each file and no text qualifier. EPA suggests importing each field into your choice of software as text. Some of
the IDs can otherwise be misinterpreted as long integer field types when they contain alpha characters. For further
assistance, please refer to the document "Instructions for Accessing Results from UCMR 5" on the UCMR Occurrence Data
web page. Additional reference material, including common questions and answers on accessing and understanding the
UCMR 5 data, is available on EPA's UCMR 5 website.
To view results or perform additional analyses, select one of the following zip files from UCMR 5 (2023-2025) Occurrence
Data:
• UCMR 5 Occurrence Data to view ALL the analytical results (i.e., results for all analytes reported by all public water
systems to date). Note that we expect the UCMR5_all.txt file to become too large to be imported into Excel once
the majority of the UCMR 5 results are reported, in which case you can try other applications (e.g., Microsoft
Access) or import a subset of the data as described below.
• UCMR 5 Occurrence Data by State to view ALL the analytical results to date, organized by Tribes and states. Within
that zip file, one text file (UCMR5_AII_Tribes_AK_LA.txt) will have all results for Tribal systems and for the states
starting alphabetically with A through L; another (UCMR5_AII_MA_WY.txt) will have all results for the states
starting alphabetically with M through W. The results are organized this way to address file size limitations and
make data management easier.
• UCMR 5 Occurrence Data by Method Classification to view ALL analytical results to date for all systems by
analytical method. Within that zip file, you will find individual text files with results organized by method (e.g., a
Method 200.7 text file with results for lithium).
The following text files for the additional data elements (i.e., parameters beyond analytical results for the 30 UCMR 5
contaminants) are also contained in the above zip files:
• UCMR5_ZipCodes.txt - U.S. Postal Service Zip Code(s) for all areas served by a PWS
• UCMR5_AddtlDataElem.txt - Additional data elements: DisinfectantType, Treatmentlnformation,
LithiumOccurrence, LithiumTreatment, PFASOccurrence, PFASTreatment, PotentialPFASSources,
Potential PFASSources Detail
o EPA is not asking PWSs for a formal, in-depth, source water evaluation for potential PFAS sources and
recognizes that some PWSs will have more complete information than others. EPA's PFAS Analytic Tools
can serve as a starting point to answer this question and are accessible here.
Table 4. Data Definitions for Text Files: UCMR5_AII, UCMR5_AII_Tribes_AK_LA,
UCMR5_AIl_MA_WY, and \JCMR5_MethodNumber
Field Name
Definition
PWS ID
Public Water System (PWS) Identification Code. The code used to identify each PWS. The code begins
with the standard 2-character postal state abbreviation or Region code; the remaining 7 numbers are
unique to each PWS in the state
PWSName
Name of the PWS
Size
Size category of the PWS for UCMR 5, based on retail population as indicated by the Safe Drinking
Water Information System (Federal) (SDWIS/FED) as of February 1, 2021: S (< 10,000), L (> 10,000)
FacilitylD
Identification code for each applicable facility associated with water treatment or delivery at the PWS
FacilityName
Name of the facility at the PWS
FacilityWaterType
Source of water at the facility: SW (surface water), GW (groundwater), GU (groundwater under the
direct influence of surface water), MX (Any combination of: SW, GW, and GU)
SamplePointID
Identification code for each sample point location at a PWS
SamplePointName
Name of the sample point at the PWS
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EPA 815-S-23-003
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Field Name
Definition
SamplePointType
Sampling Point Type Code: EP (entry point to the distribution system)
AssociatedFacilitylD
Null for UCMR 5
AssociatedSamplePointID
Null for UCMR 5
CollectionDate
Date of sample collection (month, day, year)
SamplelD
Identification code for each sample
Contaminant
The UCMR 5 contaminant analyzed
MRL
Minimum Reporting Level (MRL) defined by UCMR 5 in |ag/L for the contaminants
Units
Units of the MRL and analytical results: ng/L
MethodID
Identification code of the analytical method
AnalyticalResultsSign
Sign indicating whether the analytical result is less than (<) the MRL or equal to (=) a numeric value at or
above the MRL
AnalyticalResultValue
Numeric value of the analytical result in pg/L for the contaminants. Null values represent less than MRL
SampleEventCode
Identification code for each sample event: SE1, SE2, SE3, SE4
MonitoringRequirement
AM (Assessment Monitoring)
Region
EPA Region (states): 1 (CT, ME, MA, NH, Rl, VT), 2 (NJ, NY, PR [Puerto Rico], VI [Virgin Islands]), 3 (DE,
DC, MD, PA, VA, WV), 4 (AL, FL, GA, KY, MS, NC, SC, TN), 5 (IL, IN, Ml, MN, OH, Wl), 6 (AR, LA, NM, OK,
TX), 7 (IA, KS, MO, NE), 8 (CO, MT, ND, SD, UT, WY), 9 (AZ, CA, HI, NV, AS [American Samoa], GU [Guam],
MP [Northern Marianas Islands], NN [Navajo Nation]), 10 (AK, ID, OR, WA)
State
State abbreviation; Tribal PWSs without primacy are attributed to an EPA Region (01, 02, 03, 04, 05, 06,
07, 08, 09, 10)
UCMRlSampleType
Null for UCMR 5
Table 5. Additional Data Definitions for Text File: UCMR5_ZipCodes
Field Name Definition
ZipCode U.S. Postal Service Zip Code(s) for all areas served by a PWS. This data is entered by the PWS.
Table 6. Additional Data Definitions for Text File: UCMR5 AddtlDataElem
Additional Data Element
Definition and Response Options
DisinfectantType
All of the disinfectants/oxidants that have been added prior to and at the entry point to the
distribution system. Please select ALL that apply.
PEMB = Permanganate, HPXB = Hydrogen peroxide, CLGA = Gaseous chlorine, CLOF = Offsite
generated hypochlorite (stored as a liquid form), CLON = Onsite generated hypochlorite, CAGC =
Chloramine (formed with gaseous chlorine), CAOF = Chloramine (formed with offsite hypochlorite),
CAON = Chloramine (formed with onsite hypochlorite), CLDB = Chlorine dioxide, OZON = Ozone,
ULVL = Ultraviolet light, OTHD = Other types of disinfectant/oxidant, NODU = No disinfectant/oxidant
used
Treatmentlnformation
Treatment information associated with the sample point. Please select ALL that apply.
CON = Conventional (non-softening, consisting of at least coagulation/sedimentation basins and
filtration), SFN = Softening, RBF = River bank filtration, PSD = Pre-sedimentation, INF = In-line
filtration, DFL = Direct filtration, SSF = Slow sand filtration, BIO = Biological filtration (operated with
an intention of maintaining biological activity within filter), UTR = Unfiltered treatment for surface
water source, GWD = Groundwater system with disinfection only, PAC = Application of powder
activated carbon, GAC = Granular activated carbon adsorption (not part of filters in CON, SFN, INF,
DFL, or SSF), AIR = Air stripping (packed towers, diffused gas contactors), POB = Pre-oxidation with
July 2023
Office of Water (MS-140)
EPA 815-S-23-003
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Additional Data Element
Definition and Response Options
chlorine (applied before coagulation for CON or SFN plants or before filtration for other filtration
plants), MFL = Membrane filtration, IEX = Ionic exchange, DAF = Dissolved air floatation, CWL = Clear
well/finished water storage without aeration, CWA = Clear well/finished water storage with aeration,
ADS = Aeration in distribution system (localized treatment), OTH = Other types of treatment, NTU =
No treatment used, DKN = Do not know
LithiumOccurrence
A yes or no answer provided by the PWS for each entry point to the distribution system.
Question: Have you tested for the contaminant in your drinking water in the past?
YES = If yes, did you modify your treatment and if so, what types of treatment did you implement?
(see LithiumTreatment); NO = Have never tested for the contaminant; DK = Do not know.
LithiumTreatment
If yes, select ALL that apply:
PAC = Application of powder activated carbon, GAC = Granular activated carbon adsorption (not part
of filters in CON, SFN, INF, DFL, or SSF), IEX = Ionic exchange, NRO = Nanofiltration and reverse
osmosis, OZN = Ozone, BAC = Biologically active carbon, MFL = Membrane filtration, UVL =
Ultraviolet light, OTH = Other, NMT = Not modified after testing
PFASOccurrence
A yes or no answer provided by the PWS for each entry point to the distribution system.
Question: Have you tested for the contaminant in your drinking water in the past?
YES = If yes, did you modify your treatment and if so, what types of treatment did you implement?
(see PFASTreatment); NO = Have never tested for the contaminant; DK = Do not know.
PFASTreatment
If yes, select ALL that apply:
PAC = Application of powder activated carbon, GAC = Granular activated carbon adsorption (not part
of filters in CON, SFN, INF, DFL, or SSF), IEX = Ionic exchange, NRO = Nanofiltration and reverse
osmosis, OZN = Ozone, BAC = Biologically active carbon, MFL = Membrane filtration, UVL =
Ultraviolet light, OTH = Other, NMT = Not modified after testing
PotentialPFASSources
A yes or no answer provided by the PWS for each entry point to the distribution system.
Question: Are you aware of any potential current and/or historical sources of PFAS that may have
impacted the drinking water sources at your water system?
YES = If yes, select ALL that apply (see PotentialPFASSourcesDetail); NO = Not aware of any potential
current and/or historical sources; DK = Do not know
PotentialPFASSourcesDetail
If yes, select ALL that apply:
MB = Military base, FT = Firefighting training school, AO = Airport operations, CW = Car wash or
industrial launderers, PS = Public safety activities (e.g., fire and rescue services), WM = Waste
management, HW = Hazardous waste collection, treatment, and disposal, UW = Underground
injection well, SC = Solid waste collection, combustors, incinerators, MF = Manufacturing, FP = Food
packaging, TA = Textile and apparel (e.g., stain- and water-resistant, fiber/thread, carpet, house
furnishings, leather), PP = Paper, CC = Chemical, PR = Plastics and rubber products, MM = Machinery,
CE = Computer and electronic products, FM = Fabricated metal products (e.g., nonstick cookware),
PC = Petroleum and coal products, FF = Furniture, OG = Oil and gas production, UT = Utilities (e.g.,
sewage treatment facilities), CT = Construction (e.g., wood floor finishing, electrostatic painting), OT
= Other
July 2023
Office of Water (MS-140)
EPA 815-S-23-003
Page 13 of 13
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