Lead Service Line Inventory

Sweetwater Authority has completed the initial lead service line inventory required by U.S. EPA’s Lead and Copper Rule Revisions. The deadline for the initial inventories was October 16, 2024. 

Through completing a historical records review and field investigations, Sweetwater Authority has determined it has no lead or galvanized requiring replacement service lines in its distribution system. This includes any privately-owned or customer-owned service lines.

Sweetwater Authority reviewed all applicable sources of information, including 

  • All construction and plumbing codes, permits, and existing records or other documentation which indicates the service line materials;
  • All water system records, including distribution system maps and drawings, historical records on each service connection, meter installation records, historical capital improvement or master plans, and standard operating procedures; 
  • All inspections and records of the distribution system that indicate service line material, including inspections conducted during the course of normal operations 
  • Historical lead and copper tap sampling results.

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

Sweetwater Authority used the interpolation method. The interpolation method is used when the water utility can divide their service area into uniform groups, such as neighborhoods or tracts. Each uniform group shares multiple common characteristics, such as time period built, location, or contractor. The service line materials for each group are assumed to be similar. Water utilities physically verified a percentage of the homes in that group to interpolate or determine the service line material for the remaining homes.

Sweetwater Authority created five interpolation groups (era bins) based on service installation date and verified 3-4 % (randomized) per group to achieve a statistical confidence level of 95% with a 5% margin of error. The five bins consisted of the following eras: 1888-1929, 1930-1939, 1940-1949, 1950-1959, and 1960-1986. All service lines inspected were verified non-lead (e.g. copper, plastic, and galvanized). No lead or galvanized requiring replacement service lines were identified. Service lines installed on or after January 1, 1987 were not included as the use of lead pipe material in new construction was banned by the California Health and Safety Code, Section 300.6 on January 1, 1986. 

Sweetwater Authority's drinking water continues to meet and/or exceed water quality standards.