Marin Water has completed the lead service line inventory required by U.S. EPA’s Lead and Copper Rule Revisions and has determined that there are no service laterals requiring replacement in the distribution system. Consistent with the EPA Lead and Copper Rule, Marin Water reviewed all available information and completed field sampling to ensure no lead service laterals are present in the District’s distribution system.

Information sources included:

• Construction and plumbing codes, permits, and other documentation that indicates the service line materials;
• Water system historical records, including distribution system maps and drawings, meter installation records, and capital improvements;
• Operational records of the distribution system that indicate service line material, including inspections occurring during the course of normal operations (e.g., checking service line materials when reading water meters or performing maintenance activities); and
• Service line or meter replacement records.

In addition to the above sources of information, Marin Water used stratified random sampling to assess the materials of the service laterals throughout the distribution system. Stratified random sampling involves physically verifying a subset of randomly selected service lines in the distribution system. That subset is stratified or divided into groups based on certain characteristics (e.g., years the service lines were installed). Stratification allows for a sample or subset of service lines to be more representative of the service lines in the distribution system.

After investigating the subset of service lines, if no lead or galvanized requiring replacement service lines are discovered, the remaining service lines may be assumed non-lead with a certain level of confidence. Marin Water received approval of the above protocols and for the submission of its inventory of customer service laterals from the Division of Drinking Water in July 2024.

Marin Water continues to document service line material information and will update the inventory as needed. View Marin Water’s approved Work Plan for its Lead and Copper Service Line Inventory.