United States
Environmental Protection
Agency
The Fourth Unregulated Contaminant Monitoring Rule (UCMR 4)
Metals, Pesticides, Alcohols, SVOCs - Fact Sheet for Assessment Monitoring
Overview
EPA published the "Revisions to the Unregulated Contaminant Monitoring Rule (UCMR 4) for Public Water Systems and
Announcement of Public Meeting" on December 20, 2016 (81 FR 92666). UCMR 4 includes Assessment Monitoring for a total
of 30 chemical contaminants including two metals, eight pesticides plus one pesticide manufacturing byproduct, three
alcohols, and three semivolatile organic chemicals (SVOCs), as shown in the table below. UCMR 4 also requires Assessment
Monitoring for:
•	Three brominated haloacetic acid (HAA) disinfection byproducts groups and the indicators total organic carbon
(TOC) and bromide.
•	Nine cyanotoxins and one cyanotoxin group.
Monitoring under UCMR 4 will occur from 2018-2020. For more information on these contaminants, please refer to the
respective UCMR 4 Fact Sheets.
Assessment Monitoring (Metals, Pesticides, Alcohols, SVOCs)
Metals: EPA Method 200.8, ASTM D5673-10, SM 31253
Contaminant
CASRN1
MRL2
(Hg/L)
Additional Information
germanium
7440-56-4
0.3
Naturally-occurring element; commercially available in combination with
other elements and minerals; a byproduct of zinc ore processing; used in
infrared optics, fiber-optic systems, electronics and solar applications
manganese
7439-96-5
0.4
Naturally-occurring element; commercially available in combination with
other elements and minerals; used in steel production, fertilizer,
batteries and fireworks; drinking water and wastewater treatment
chemical; essential nutrient
Pesticides and a Pesticide Manufacturing Byproduct: EPA Method 525.3
Contaminant
CASRN1
MRL2
(Hg/L)
Additional Information
alpha-hexachlorocyclohexane
319-84-6
0.01
Component of benzene hexachloride (BHC); formerly used as an
insecticide
chlorpyrifos
2921-88-2
0.03
Organophosphate; used as an insecticide, acaricide and miticide
dimethipin
55290-64-7
0.2
Used as an herbicide and plant growth regulator
ethoprop
13194-48-4
0.03
Used as an insecticide
oxyfluorfen
42874-03-3
0.05
Used as an herbicide
profenofos
41198-08-7
0.3
Used as an insecticide and acaricide
tebuconazole
107534-96-3
0.2
Used as a fungicide
total permethrin (cis- & trans-)
52645-53-1
0.04
Used as an insecticide
tribufos
78-48-8
0.07
Used as an insecticide and cotton defoliant
Alcohols: EPA Method 541
Contaminant
CASRN1
MRL2
(Hg/L)
Additional Information
l-butanol
71-36-3
2.0
Used as a solvent, food additive and in production of other chemicals
2-methoxyethanol
109-86-4
0.4
Used in a number of consumer products, such as synthetic cosmetics,
perfumes, fragrances, hair preparations and skin lotions
2-propen-l-ol
107-18-6
0.5
Used in the production flavorings, perfumes and other chemicals
Office of Water (MS-140)
EPA 815-F-16-009
December 2016

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Semivolatile Chemicals: EPA Method 530
Contaminant
CASRN1
MRL2
(Hg/L)
Additional Information
butylated hydroxyanisole
25013-16-5
0.03
Used as a food additive (antioxidant)
o-toluidine
95-53-4
0.007
Used in the production of dyes, rubber, pharmaceuticals and pesticides
quinoline
91-22-5
0.02
Used as a pharmaceutical (anti-malarial) and flavoring agent; produced as
a chemical intermediate; component of coal
1.	CASRN - Chemical Abstracts Service Registry Number
2.	MRL - Minimum Reporting Level
3.	ASTM - ASTM International; SM - Standard Methods
¦	Applicable Water Systems: Community water systems (CWSs) and non-transient non-community water systems
(NTNCWSs) serving more than 10,000 retail customers (i.e., large systems) and a representative sample of 800 CWSs and
NTNCWSs serving 10,000 or fewer retail customers (i.e., small systems).
¦	Timeframe and Frequency: For surface water and ground water under the direct influence of surface water systems,
sampling will take place for four consecutive quarters over the course of 12 months; a total of four sampling events that
occur three months apart. For ground water systems, sampling will take place twice over the course of 12 months; a total of
two sampling events that occur five to seven months apart.
¦	Monitoring Locations: Sample collection will take place at the entry point to the distribution system (EPTDS). With prior
approval, large ground water systems that have multiple EPTDSs can sample at representative sampling locations rather
than at each EPTDS. Systems that purchase water with multiple connections from the same wholesaler may select one
representative connection from that wholesaler. This EPTDS sampling location must be representative of the highest annual
volume connections.
¦	Laboratories: Samples must be analyzed by EPA UCMR approved laboratories.
¦	Occurrence Data: The analytical results from UCMR 4 are stored in the National Contaminant Occurrence Database (NCOD).
For a summary of the NCOD results, tips for querying NCOD, and health effects information (including reference
concentrations, where available), please refer to the UCMR 4 Data Summary document.
Critical Deadlines and Requirements
Following Rule Publication
Due Date
Requirement
Report
through
SDWARS1
Contact
Sampling
Coordinator2
December 31, 2017
Large systems must update contact information, zip code(s),
sampling location(s), inventory information and monitoring
schedule. With the exception of monitoring schedule changes,
any subsequent changes must be submitted within 30 days of
the change occurring. EPA will coordinate with the small
systems to collect the contact information, zip code(s) and
inventory information. After December 31, 2017, systems
must provide an explanation for any requested schedule
change and obtain EPA approval of the change.
X
X
(after
December
31, 2017)
February 21, 2017
Laboratories seeking approval must submit a registration
form to participate in the laboratory approval process.

X
April 19, 2017
Laboratories must complete and submit the necessary
laboratory approval application materials.

X
October 31, 2017
Large ground water systems that wish to monitor from
representative EPTDSs must submit their plan previously
approved by EPA or a state (i.e., under a prior UCMR cycle) or
a proposal for a new representative sampling plan. Note: the
original deadline of April 19, 2017 was extended to provide
greater opportunities for PWSs to reduce their monitoring.

X
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Following Sample Collection
Due Date
Requirement
Report
through
SDWARS1
Contact
Sampling
Coordinator2
Within 120 days of
sample collection
Laboratories post data to SDWARS.
X

Within 60 days of
lab posting data
PWSs review and approve the data. If the PWS has not taken
action after 60 days, the data are considered approved and
ready for state and EPA review.
X

1.	Safe Drinking Water Accession and Review System.
2.	Contact via email at UCMR Sampling Coordinator(5)epa.gov.
Data Elements
EPA will collect the following data elements in SDWARS4, an updated version of the data reporting system used in previous
UCMR actions.
Public Water System
Identification
(PWSID) Code
Sampling Point
Identification Code
Sample Collection Date
Analysis Batch
Identification Code
Laboratory
Identification Code
Public Water System
Name
Sampling Point Name
Sample Identification
Code
Analysis Date
Sample Event Code
Public Water System
Facility Identification
Code
Sampling Point Type
Code
Contaminant
Sample Analysis Type

Public Water System
Facility Name
Disinfectant Type
Analytical Method
Code
Analytical Results-Sign

Public Water System
Facility Type
Treatment Information
Extraction Batch
Identification Code
Analytical Result-
Measured Value

Water Source Type
Disinfectant Residual
Type
Extraction Date
Additional Value

Additional Information
The Public Notification Rule (40 CFR 141.207) requires PWSs to notify the persons served of the availability of the
results no later than 12-months after monitoring results are known. CWSs may include their public notice within
their Consumer Confidence Reports (CCRs).
Under the Consumer Confidence Report (CCR) Rule (40 CFR 141.153(d)) requires CWSs to report the monitoring
results whenever unregulated contaminants are detected. CCRs are to be sent to all billing customers each year by
July 1. (The CCR Rule does not apply to non-community water systems). To obtain a copy of your CCR, you should
contact your water supplier or you may find information for how to obtain a copy of the CCR in your water bill.
Additional information about the CCR including detains on reporting requirements can be found on the CCR
Homepage.
For More Information
¦	Safe Drinking Water Hotline: 1-800-426-4791
¦	CDX/SDWARS Help Desk: 1-888-890-1995
¦	UCMR Homepage
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