Utilities staff explain lead sampling, consumer‑confidence updates after monitoring/reporting error

Steve Perez, deputy director for regulatory compliance at Las Cruces Utilities, explained how the Lead and Copper Rule sampling and compliance calculation works and why the 90th‑percentile is used. "If the 90th percentile of sample results are greater than 0.015 mg/L, you have an exceedance," Perez said, walking the council through a sample calculation that showed a 90th‑percentile of 0.009 mg/L in his example.

Perez also addressed a non‑emergency monitoring and reporting violation from November that led to an August public notice. He said staff resampled the locations and found no confirmed contamination: additional samples and supply‑well testing came back negative. Perez told council the error was on lab paperwork that made it appear required samples were not completed, and that Utilities will send notices sooner in the future rather than waiting for annual Consumer Confidence Reports. The department also said it will issue revised CCR tables for University Estates after New Mexico regulators required separate tables for that supply source.