Though the issue may have subsided in the public consciousness since Flint, MI, first declared a public health emergency in late 2015, the presence of lead in drinking water is still very much top of mind for drinking water systems all over the country.
While many have taken steps to remove lead at the tap, the fundamental fix for this problem seems to be the replacement of the outdated lead service lines (LSLs) that introduce the contaminant into treated water as it travels to consumers. But without any assistance, the full replacement of LSLs can be an impossible task for many utilities.
In order to advance this much-needed process, the American Water Works Association (AWWA), a utility membership group offering information and other resources, has introduced its “C810-17 Standard for Replacement and Flushing of Lead Service Lines.”
“AWWA’s new standard is intended to describe essential procedures for the replacement of lead service lines, including … [the] appropriate tools and techniques; flushing of service lines after replacement; instructions to inform customers affected by the replacement, including additional risk reduction measures; and verification of lead level management prior to return of service,” said Paul Olson, senior manager of standards programs for AWWA. “Although partial lead service line replacements are discouraged, this standard also describes procedures for partial replacement and repair situations where full service line replacement is not possible or practical.”
AWWA estimates that there are still 6.1 million LSLs utilized by water systems around the country. While that’s a staggering number given the known dangers that these lines present for consumers, it does mark a drop compared to the 10.2 million estimated LSLs when the U.S. EPA’s Lead and Copper Rule was first introduced in 1991.
Those utilities that access the AWWA standard will find details on three approaches to LSL replacement and will be able to pursue the one that best fits their specific site details.
There is information on open cut full replacement, a traditional approach that involves excavating the full length of the service line to be replaced; trenchless replacement on new routes, which involves boring with directional drilling or hydraulic ramming tools to pull in a new service line on a new route while leaving the old line where it is; and trenchless replacement of existing routes, which includes things like pipe-splitting or removing the existing LSL and installing a new one.
“The standard emphasizes full LSL replacement,” said Olson. “When full replacement is not possible, the partial replacements use the same practice elements as full replacement. When partial replacements occur, there is greater emphasis on post-replacement flushing and other measures, like the use of water filters to address any increase in lead levels immediately following the partial replacement.”
As it can be such a critical step, the standard providers readers with details on how to conduct line flushing to ensure that a utility is doing more good than harm when it undergoes LSL replacement.
“Full and partial LSL replacement and other similar disturbances can potentially increase the release of lead-containing particulates,” Olson said. “The use of high-velocity flushing is an important step to preemptively dislodge and remove particulate lead following partial LSL replacements in order to remove those particulates prior to regular water use. Guidance for flushing includes an initial flushing procedure immediately after LSL replacement and guidance for continued flushing after replacement by the homeowner.”
Ultimately, the standard will only be as helpful as water systems can make it. And it does nothing to address possibly the biggest obstacle preventing wide-scale LSL replacement: lack of funding. But as the number of LSLs in the nation continues to dwindle, the availability of this standard will provide those utilities fortunate enough to purge themselves of outdated pipelines with an informed way of doing so.
“The consensus standard development process is intended to provide consistent practices and techniques for water systems and their contractors,” Olson said. “In this instance, that means recommendations for tools and techniques, communications with customers, flushing, and verification of replacement. A successful consensus standard aids in successful utility operations consistent with the best available information to inform practice.”
Image credit: "Rusty Pipes" trudieh, 2007, used under an Attribution 2.0 Generic license: https://creativecommons.org/licenses/by/2.0/