By Andrew Eaton, PhD, BCES

On May 2, US EPA Administrator, Lisa P. Jackson signed the third Unregulated Contaminant Monitoring Rule (UCMR3), requiring all water utilities serving a population of more than 10,000 to monitor for 28 contaminants beginning in January 2013. The new testing requires use of US EPA-specified analytical methods and only laboratories approved by the agency specifically for UCMR3 monitoring can report testing results, which makes it important for public water utilities to find a good laboratory partner to conduct their monitoring.

Understanding UCMR3
Amendments to the Safe Drinking Water Act (SDWA) in 1996 required US EPA to establish a program for monitoring unregulated contaminants every five years. Overall, the program provides the agency with scientifically valid data on the occurrence of the monitored contaminants in drinking water and assists in developing regulatory decisions for each contaminant. Beginning in January 2013, UCMR3 will require all water utilities serving a retail population of more than 10,000 to conduct one year of monitoring for contaminants (see Table 1). These compounds include metals, hormones, volatile organics, 1,4-dioxane, chlorate and perfluorinated compounds. The rule also requires monitoring for hexavalent chromium—a contaminant that gained notoriety with the release in 2000 of the film Erin Brockovich.

Required UCMR3 contaminants are divided into two lists. List 1: Assessment Monitoring, as shown in Table 2, includes 21 compounds listed in six individual US EPA methods (200.8, 218.7, 300.1, 522, 524.3 and 537). Any system, including 100-percent consecutive systems, serving a retail population of more than 10,000, must monitor according to List 1.

The make-up of the 21 compounds includes:

  • Seven volatile organic compounds
  • One synthetic organic compound (1,4-dioxane)
  • Five metals (chromium, cobalt, molybdenum, strontium, vanadium)
  • One oxyhalide anion (chlorate)
  • Six perfluorinated compounds
  • Hexavalent chromium

List 2: Screening Monitoring (see Table 3) includes seven natural and synthetic hormones (US EPA Method 539) for monitoring. All very large systems serving a retail population of more than 100,000 must monitor for List 2 . A randomly selected set of 320 systems serving a retail population of more than 10,000 must also monitor for List 2.

UCMR3 considerations
To help the water and wastewater community better understand the rules and timeline associated with UCMR3 monitoring rules, below are tactical questions and answers to consider.

Where do you monitor?
All entry points to the distribution system (EPTDS) must be sampled. Additionally, samples must also be collected at the distribution system maximum residence time (DSMRT) for metals (US EPA Method 200.8), hexavalent chromium (US EPA Method 218.7) and chlorate (US EPA Method 300.1). The DSMRT location should be the farthest point relative to the EPTDS and is generally a Stage 2 Disinfection Byproduct Rule-identified sampling point. US EPA’s Safe Drinking Water Accession and Review System (SDWARS) database is pre-populated with UCMR2 sample locations and proposed sampling dates and public water utilities may review and edit this information in SDWARS for UCMR3 until October 12.

What about field blanks?
Because of low reporting limits required in UCMR3, four of the analytical methods (metals: 200.8, volatiles: 524.3, perfluorinated compounds: 537 and hormones: 539) require collection of a field blank with each sample to verify that any detects are not the result of field contamination. The testing laboratory must provide specific instructions and supplies for collection and handling of field blanks, which differs from method to method. If any analytes are detected in a sample, the field blank must also be analyzed, and if there are any detects in that field blank, the sample results will be considered invalid and will require re-collection. Table 4 provides information on where to monitor and which methods require field blanks.

Table 4. Monitoring locations and field blank requirements by contaminant

What if you buy water from a wholesaler and have multiple turnouts?
Public water utilities that use a wholesaler’s water and have multiple turnouts, or locations where a retail water company has a connection to the wholesaler source, can sample at a representative turnout (for any number of connections to the same source) rather than sampling at all turnouts. However, the utility must choose the turnout with the highest volume at the entry point. If that turnout is not operating at the time of scheduled sampling, then an alternate turnout must be sampled.

Can you use representative samples if you are a groundwater system with multiple entry points?
If a public water utility already had a ‘representative sampling plan’ in place for UCMR2 monitoring, those sites are pre-loaded into SDWARS by the agency and are, by default, approved for use in UCMR3. To edit the existing representative sampling plan, a public water utility must submit a proposed new plan to US EPA by August 1. When identifying a representative well, it must be representative of the highest producing, based on annual volume, and most consistently active wells. In addition, the representative well must be in use at the scheduled sampling time. An alternative location must be sampled if the representative EPTDS is not available at the time of scheduled sampling.

When and how often do you monitor?
Monitoring must commence on or after January 1, 2013 and conclude by December 31, 2015. US EPA has pre-populated SDWARS with each utility’s designated start date; however, a utility may modify its schedule to meet particular operational or budgetary constraints any time before October 1. Groundwater systems must sample twice in one year, five to seven months apart. Surface water systems must monitor quarterly for one year. For the second and subsequent sampling events, if the designated sample location is not operational for one month before or after the scheduled sampling, the public water system must contact US EPA to establish a revised sample schedule.

When do you report your results to US EPA?
Laboratories have 120 days after sampling to post their results for utility approval. Once posted, the public water utility will receive notification electronically to review and approve the data submitted by the laboratory, which needs to occur within 60 days. If no action is taken within the 60-day time frame, the data is automatically uploaded to the National Contaminant Occurrence Database.

What else do you need to report?
There are a number of pieces of information in addition to lab results that must be reported. Many of these are reported by the laboratory, such as sample event code, sample date and analysis date; however, there are some that the public water utility must report, including all disinfectant type(s) being used for each sampling point, the sample location type, facility ID, sample point ID and water source type. Many of these, with the exception of the disinfectant information, can be pre-populated in the database to streamline the data entry. There are also some one-time reporting requirements, such as zip codes for all customers and contact information.

Approved laboratories
In order to prepare for UCMR3 monitoring, public water utilities should partner with a credible laboratory for testing. Only laboratories approved specifically for UCMR3 testing by US EPA can report results. The agency will publish a list of all approved laboratories in the coming weeks. Each approved laboratory will undergo ongoing audits by US EPA in order to retain approval. Due to the complexity of the methods, however, utilities need to be sure to select a lab with a demonstrated track record of extensive experience with the methods.

About the author
Andrew Eaton, PhD, BCES, is Technical Director at MWH Laboratories (, a division of MWH, a global wet infrastructure sector leader and provider of environmental engineering, construction and strategic consulting services.

About the company
In April 2012, MWH Laboratories (MWH Labs) became one of the first commercial laboratories in the US to meet all proficiency testing requirements for UCMR3 chemistry testing and received approval effective May 2 for all UCMR3 community water supply required monitoring. MWH Labs provided US EPA and the American Water Works Association with expert review on all of the prior UCMR regulations, beginning with UCMR1 in 2001. The MWH Labs team also co-authored the official US EPA Method (314.0) for perchlorate analysis that was used in UCMR1 and served as an official agency method validator for many of the UCMR3 test methods, including 524.3, 200.8, 218.7, and 539. During UCMR1 and UCMR2, MWH Labs served as a primary US EPA contractor for monitoring UCMR compounds for small systems across the country. In these contracts, MWH Labs analyzed over 3,000 samples using a variety of methods, including 524.2, 525.2, 515.4, 314, 521, 526, 527, 528, 529, 532 and 535, with quality control requirements exceeding Federal regulations, and received excellent contract performance reviews from the agency. Additionally MWH Labs conducted more than 30 percent of the required UCMR2 testing for large utilities, far more than any other lab in the country. All of the UCMR3 chemical methods are already in production at MWH Labs, which gives clients the opportunity to do preliminary monitoring to determine potential vulnerability to UCMR3 contaminants.



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