Monitoring Unregulated Drinking Water Contaminants

Laboratory Approval Program for the Fourth Unregulated Contaminant Monitoring Rule (UCMR 4)

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Basic information about the UCMR 4 laboratory approval program

All laboratories conducting analyses for the Unregulated Contaminant Monitoring Rule (UCMR) must be approved by EPA.

The UCMR laboratory approval program only applies to laboratories that wish to analyze samples for the fourth Unregulated Contaminant Monitoring Rule (UCMR 4). Laboratories wishing to conduct UCMR 4 analyses are required to successfully complete a registration and application process according to a specified schedule before receiving approval from EPA.

Laboratories are encouraged to apply for method-specific UCMR 4 approval as early as possible, as EPA anticipates that large Public Water Systems (PWSs) scheduled for monitoring in the first year (2018) will be making arrangements for sample analyses soon after the final rule is published. See discussion of step-by-step process for important deadlines.

  • The UCMR 4 list of approved laboratories will initially be made available by mid-2017 and updated as needed.

The laboratory approval program is designed to assess whether laboratories meet the required criteria described under UCMR 4 for:

  • Equipment
  • Laboratory performance
  • Data reporting

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Step-by-step laboratory approval process

Applicants already certified for UCMR 4 methods by their state or EPA Region to conduct drinking water analyses still need to complete the UCMR 4 approval steps, including analyzing the UCMR 4 proficiency test (PT) sample. The steps for the laboratory approval process are:

1. Request to participate
Laboratories interested in the UCMR 4 laboratory approval program must first email EPA at: to request registration materials.

2. Registration
Laboratory applicants provide registration information that includes: laboratory name, mailing address, shipping address, contact name, phone number, email address and a list of the UCMR 4 methods for which the laboratory is seeking approval. This registration step provides EPA with the necessary contact information, and ensures that each laboratory receives a customized application package. Laboratories must complete and submit the necessary registration information by February 21, 2017.

3. Application package
Laboratories complete and return a customized application package that includes the following: IDC data, including precision, accuracy and results of MRL studies; information regarding analytical equipment and other materials; proof of current drinking water laboratory certification (for select compliance monitoring methods); and, example chromatograms for each method under review. Laboratories must complete and submit the necessary application materials by April 19, 2017.

As a condition of receiving and maintaining approval, the laboratory is expected to confirm that it will post UCMR 4 monitoring results and quality control data that meet method criteria (on behalf of its PWS clients) to EPA's UCMR electronic data reporting system, the Safe Drinking Water Accession and Review System (SDWARS).

4. EPA’s review of application package
EPA will review the application packages and, if necessary, request follow-up information. Laboratories that successfully complete the application process become eligible to participate in the UCMR 4 PT program.

5. Proficiency testing
A PT sample is a synthetic sample containing a concentration of an analyte or mixture of analytes that is known to EPA, but unknown to the laboratory. To be approved, a laboratory is expected to meet specific acceptance criteria for the analysis of a UCMR 4 PT sample(s) for each UCMR analyte in each method, for which the laboratory is seeking approval. EPA intends to offer up to four opportunities for a laboratory to successfully analyze UCMR 4 PT samples.

A laboratory is expected to pass one of the PT studies for each analytical method for which it is requesting approval, and will not be required to pass a PT study for a method it already passed in a previous UCMR 4 PT study. EPA does not expect to conduct additional PT studies after the start of system monitoring; however, laboratory audits will likely be ongoing throughout UCMR 4 implementation. Initial laboratory approval is contingent on successful completion of a PT study. Continued laboratory approval is contingent on successful completion of the audit process and satisfactorily meeting all the other stated conditions.

6. Written EPA approval
After successfully completing the preceding steps 1 through 5, EPA will send each laboratory a letter listing the methods for which approval is granted.

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Maintaining laboratory approval

Approved laboratories must adhere to the quality assurance and quality control procedures and criteria outlined in the method(s) and rule language to maintain their approval status.

Laboratories are also required to post occurrence data and required quality control data electronically via the Safe Drinking Water Accession and Review System (SDWARS) within 120 days of sample collection date. Failure to post data using SDWARS will generally result in EPA revoking the laboratory's approval status.

Once a laboratory is disapproved, EPA does not anticipate any opportunity for reinstatement during the UCMR 4 monitoring period. Approved laboratories are subject to on-site laboratory and/or off-site (paper) audits.

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