Do Lead and Copper Rule Sampling Requirements Tell Us What We Need to Know About Lead in Water?
The U.S. Environmental Protection Agency (EPA) recently proposed Lead and Copper Rule Revisions (LCRR), with the public comment period ending on February 12, 2020. In the proposal, EPA requested comments on whether water systems with lead service lines should be required to collect tap samples that are representative of water that was in contact with lead service lines during the 6-hour stagnation period. The EPA LCR and the proposed LCRR requires water systems to collect the first liter of water from the tap after the stagnation period; this first liter typically does not include water from the lead service line, which is the largest source of lead in contact with drinking water. The first liter sample can potentially show the risk of lead release from internal plumbing, but it does not capture the highest risk water in a building with a lead service line.
This analysis demonstrates that lead samples collected according to the LCR and proposed LCRR sampling protocol are not achieving their purpose of identifying high lead in the water and correcting it via corrosion control. Michigan water systems with lead service lines had lead action level exceedances at 3x the number of systems The data indicate that if corrosion control is not working to reduce lead levels, it is more likely to be identified in the 5th liter sample than the 1st liter sample of the LCRR proposal. If the final LCRR requires only first liter compliance samples, only a small fraction of PWSs with high lead levels will be identified and triggered into the more protective provisions of the rule.
In addition to revising compliance sampling protocols, a comprehensive verified service line inventory will also be a game changer for measuring and addressing risk of lead exposure at public water systems. Although a lead service line inventory was proposed in the LCRR, many additional details included in other sections of my comments are necessary to make the inventory requirement reliable, complete, and meaningful.
On a national scale, once PWSs use comprehensive verified service line inventories to select the LCR sampling pool, collecting fifth liter samples is likely to identify an even larger percentage of PWSs where corrosion control is not reducing lead levels as much as current compliance sampling indicates. This in turn means that current exposure to lead in water is likely much higher than estimated under current compliance sampling procedures.
