Lead Service Line Inventory

Western Water completed the Lead Service Line Inventory (LSLI) in October 2024, and lead has not been identified in Western Water’s service area. Through historical records review and field investigations, Western Water has determined that there are no lead or galvanized service lines requiring replacement in its Riverside, Murrieta, and Rainbow systems, excluding March Air Reserve Base (see Western Water's retail service area map). This includes privately owned and customer-owned service lines.

Western Water has reviewed all applicable sources of information, including:

• Available construction and plumbing codes to assess historical regulation of lead service line disallowance (e.g. National Lead Ban, State Codes, County Codes, the standards and codes of the cities incorporated before 1986, including the city of Riverside);
• Water system records which indicate the service line materials, customer data, county parcels, historical capital improvement or master plans; and
• Water distribution system records, which indicate the service line materials, geographic information system (GIS) data, distribution system maps and drawings, as-builts, historical lead and copper tap sampling results from 1992-2022, meter installation records, work orders, and inspections conducted during normal operations, including "2018 Lead Service Line Investigation Report Results" and “2020 Pipe Data Analysis developed by Black and Veach.”

In addition to reviewing the above sources of information, Western Water used an alternative method to develop the LSLI that was approved by the State Water Resources Control Board on a case-by-case basis.

Western Water used indirect interpolation and stratified random sampling approaches to develop the LSLI. Both approaches involve physically inspecting a representative subset of service lines to confirm non-lead materials, with the indirect interpolation approach being more suitable for homogeneous communities. The 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.

Western Water inspected 37 sites on the utility side only, 1,071 sites on the customer side only, and 46 sites on both sides. All the service lines were inspected to be non-lead. No lead or galvanized service lines requiring replacement were identified. After investigating a statistically significant subset of service lines, the remaining service lines were classified as non-lead service lines.

After October 2024, Western Water will continue to document service line material information obtained through normal operations, such as service line maintenance and repair or meter replacement, and will update the LSLI accordingly.

If you have questions about the LSLI process, contact Western Water’s Environmental and Regulatory Compliance team at 951.571.7104 or via email.