Carrying Out The EPA's Long Term 2 Enhanced Surface Water Treatment Rule

For nearly a decade, public utilities that draw from surface waters have been contending with a developing regulation that is emblematic of the U.S. EPA and the systems under its charge. It simultaneously demonstrates the protracted, methodical nature of setting new quality measures, the reliance on the individual systems that carry out these rules to make sure they are effective, and the minutiae that go into satisfying a government body charged with defending public health.

The EPA’s “Long Term 2 Enhanced Surface Water Treatment Rule” (LT2) was instituted to combat the presence of disease-causing microorganisms, namely Cryptosporidium, in drinking water.

Cryptosporidium is known to cause gastrointestinal illness that may prove severe in the young or elderly and may prove fatal in those with immune systems weakened by prevailing disease. Its presence became a particular concern for the EPA as recent data indicated that high-risk systems still harbored the chlorine-resistant microorganism despite traditional treatment.

A quick perusal of the EPA’s LT2 “basic information” website will answer the most fundamental questions about the rule. It applies to all public water systems that use surface water (about 14,000 nationwide). Systems have been expected to monitor their water sources to determine treatment requirements, taking regularly scheduled samples and submitting them to the EPA to determine the presence of Cryptosporidium. For the largest systems, this monitoring began in 2006 and for smaller systems, in 2008. A second round has been initiated this year.

Per an EPA webinar from July 30, 2015, which has since been taken offline, the second round’s monitoring start dates are staggered based on size. Systems serving at least 100,000 consumers had to begin their second round of monitoring no later than April 2015. Those serving fewer than 50,000 have until October of 2016 to begin monitoring. If your system serves 10,000 or more, you’re expected to submit monthly samples over two years.

If a system serves fewer than 10,000, it can choose to sample once every two weeks for one year instead of once a month over two years. To reduce costs, these small systems will first monitor for Escherichia coli (E. coli) and if it proves prevalent, move on to test for Cryptosporidium. The second round of E. coli monitoring is scheduled to begin in October of 2017.

There are special conditions in place for systems that don’t have their own surface water source or operate seasonally. Compositing or averaging samples is permitted for plants with multiple sources of influent.

Systems have been required to report their sampling schedules and locations before the start of this second round of monitoring. After it starts, they must provide the monitoring results and, six months after its completion, a calculation of what “bin” or treatment category they fall in. The EPA expects most systems to find themselves in the lowest bin, the occupants of which will face no additional treatment requirements. Those in the higher bins, designated as such because their samples indicated high levels of contaminants, will have to provide additional treatment.

Laboratories that test the samples for Cryptosporidium are required to do so using EPA Methods 1622, 1623, or 1623.1, all of which use similar processes. Samples are required to be 10 L or “as much water as can be filtered through two filters before filters clog” in size.

A video overview of the EPA’s Cryptosporidium and Giardia detection methods can be found here. A video review of the EPA’s laboratory reports and quality control for Cryptosporidium analyses can be found here.

If nothing else, the above is an appreciation of the fact that when it’s all said and done, some utilities will still be submitting surface water samples in 2021. The results of those will finally help them comply with a rule that came into effect in March of 2006. Whatever the pressing concerns posed by Cryptosporidium, they were not enough to instigate any shortcutting to rush its treatment. This speaks to the expense of public water treatment and to the delicate, time-consuming science behind it. For those that think this is an industry slow to adapt, look no further for proof, for justification, than the Long Term 2 Enhanced Surface Water Treatment Rule.