The Revised Total Coliform Rule

Every week, many of the operators reading this article spend their morning driving from sample station to sample station, very carefully filling little 100 mL bottles with water from their distribution system.  Once per quarter or per month, they probably do the same thing for the water from each and every operating well.  And if they work at a surface water treatment plant, they take a great many more of those samples.  They cap the bottles, label them appropriately, and prepare them for transport to the laboratory where they will be tested for Total Coliform (TC) Bacteria.  If the test is positive, then the sample will also be tested for a specific TC bacteria, Escherichia coli, more commonly known as E. coli.  So what is a coliform bacterium and why do we test for it?  Coliform bacteria are defined as rod-shaped Gram-negative non-spore forming bacteria which can ferment lactose with the production of acid and gas when incubated at 35-37°C¹.  That’s a mouthful!  In other words, a coliform bacteria is one that gives a positive test result; not a real meaningful definition.  In theory, the coliform test is used to try and detect bacteria that may be present because of contamination by animal feces, sewage, or sewage contaminated water.  A great many of the bacteria that live in the gut of mammals like humans are coliform bacteria.  However, coliform bacteria can and do live just about anywhere: in the soil; in surface and groundwater; in and on plants, flowers and fruits; everywhere!  So just because there may be a positive coliform sample doesn’t mean that the water is contaminated.  It is just an indicator that there could possibly be a problem, and that you should do some investigating to see if there are any problems you weren’t aware of in your system: maybe a leak, an unprotected backflow situation, low chlorine residuals, etc.   We are required to test for these bacteria in the distribution system by the Total Coliform Rule (TCR), and there are very specific steps that must be taken if a test result is positive, such as taking repeat samples.  The TCR has been revised recently to better reflect the fact that a positive result does not necessarily mean there is contamination.  On February 13, 2013, EPA published in the Federal Register the revisions to the TCR (RTCR), which are now set to take effect in March 2016.  Key provisions of the revised TCR include²:

·         Maintains the routine sampling structure of the original TCR

·         Reduces the required number of follow-up samples (repeat and additional routine) for systems serving ≤1,000

·         Like TCR, reduced monitoring is available for small systems

·         Provides more stringent criteria that systems must meet to qualify for and stay on reduced monitoring

·         Requires small systems with problems to monitor more frequently

·         RTCR requires Public Water Systems to investigate the system and correct any sanitary defects found when monitoring results show the system may be vulnerable to contamination

·         Systems must conduct a basic self assessment (Level 1) or a more detailed assessment by a qualified party (Level 2) depending on the severity and frequency of contamination

·         Failure to assess and correct is a Treatment Technique (TT) violation

·         Notify public within 24 hours if system confirms fecal contamination (E. coli)

·         Total Coliform MCL/ acute violation is eliminated

·         Notify public within 30 days if system does not investigate and fix any identified problems

·         Notify public yearly regarding monitoring, reporting and recordkeeping violations

The Revised Total Coliform Rule is a good thing, no doubt about it.  It removes stringent regulations regarding total coliform bacteria, which turned out to be not as good an indicator of fecal contamination as it was once thought.  Instead, it relies more heavily on the investigation and correction of distribution system issues that could potentially be a source of contamination into the system.  And maintaining the treatment and distribution systems are, of course, what those same operators who go out and collect all these samples do on an every day basis anyway.

For more information on the Revised Total Coliform Rule, go to EPAs website at

http://water.epa.gov/lawsregs/rulesregs/sdwa/tcr/regulation_revisions.cfm

1.       American Public Health Association, Standard Methods for the Examination of Water and Wastewater, 19th ed., APHA, Washington, DC, 1995

2.       http://water.epa.gov/lawsregs/rulesregs/sdwa/tcr/upload/rtcrwebinar41013-1-2.pdf