Lessons from the first year of compliance sampling under Michigan's revised Lead and Copper Rule and national Lead and Copper Rule implications

Michigan revised its Lead and Copper Rule (LCR) in 2018 to include a new sampling protocol intended to better measure the amount of lead in water from lead service lines.  Water utilities completed their first round of sampling using this new protocol in 2019.  To help determine the impact of new sampling protocols, my team and I conducted an analysis of the first year of sampling results which was recently published in an open access article in the journal Water Science.

This analysis is particularly timely given today’s announcement from EPA that the January 2021 Lead and Copper Rule Revisions will go forward while a new effort to revise the rule (the Lead and Copper Rule Improvements) is reopened.  The now effective Lead and Copper Rule Revisions will require water utilities with lead service lines to collect all their compliance samples at sites with lead service lines, and collect only fifth liter samples at those locations. Data from Michigan demonstrate the impact of switching to an all-lead-service-line sampling pool, as well as the impact of collecting fifth liter samples.  Michigan's LCR results reveal the percentage of public water systems with lead service lines exceeding the lead action level (15 ppb) increasing to 13% compared to 2% under the previous sampling protocol.

Dropping first-liter samples will prevent us from learning this important context, and will dilute the number of lead action level exceedances found under the new sampling protocol. I see this as one of many important requirements to revisit in the Lead and Copper Rule Improvements. First-liter samples provide a historical trend, a bridge connecting data from the old sampling protocol to the fifth liter sample protocol. First-liter samples represent the lead contribution from household plumbing. And, first-liter samples can contain particulate lead that has been temporarily captured in an aerator. 

While this analysis is limited to the state of Michigan, the results represent a wide range of water utility sizes and water qualities across the state, indicating the potential range of outcomes that might be experienced under the federal Lead and Copper Rule Revisions.

This analysis provides important perspectives on what lead levels we are likely to find under the Lead and Copper Rule Revisions as well as important context to consider for improving the rule in the next round of revisions.

Happy reading!

Click here to download a copy of the analysis.