WOH Lead Copper Sample Siting Plan Guide

Every community water system and non-transient non-community water system must collect first-draw tap samples from customer locations most likely to contain lead or copper contamination and document these sites in an approved siting plan filed with the state primacy agency. The Lead and Copper Rule Revisions (LCRR), effective October 16, 2024, require a tiered site selection framework based on service line material, plumbing type, and construction year. Lead action level is 0.015 mg/L (15 ppb); copper is 1.3 mg/L (1,300 ppb). There is no safe level of lead exposure (MCLG = zero).

The foundation of the siting plan is a complete Service Line Inventory that identifies the material of every service connection in the distribution system. For each address, document the utility-owned and customer-owned service line material (lead, galvanized, copper, plastic, or unknown), the basis for the determination (historical records, visual inspection, customer survey, excavation, or predictive modeling), and a plan to resolve any unknowns. Unknown service lines must be treated as lead for sampling purposes until material is confirmed through records, inspection, testing, or excavation. Systems must update their siting plans whenever the inventory changes.

Sample sites are classified into three tiers based on contamination risk. Tier 1 (highest priority) includes single-family homes served by lead or galvanized-requiring-replacement service lines, and single-family homes with copper pipe and lead solder installed after 1982. Tier 2 includes multi-family buildings with lead or galvanized lines, and buildings with copper and lead solder installed before 1983. Tier 3 includes structures with non-lead, non-galvanized service lines and no known lead solder. Fill all required sampling slots with Tier 1 sites first, then Tier 2, then Tier 3—do not skip tiers. Update the siting plan whenever a site is added, removed, or replaced, and review it whenever the service line inventory is updated.