Lead Service Line Inventory

Mission Hills Community Services District has completed the initial lead service line inventory required by the U.S. EPA's lead and copper Rule Revisions. The deadline for the initial inventories is October 16, 2024. 

Through completing a historical records review and field investigations, Mission Hills Community Services District reviewed all applicable sources of information, including: 

• All construction and plumbing codes, permits, existing records, and other documentation that indicates the service line materials; 
• All water system records, including distribution system maps and drawings, historical documents, historical capital improvement or master plans, and standard operating procedures; and 
• All inspections and records of the distribution and records of the distribution conducted during normal operations (e.g., checking service line materials when reading water or performing maintenance activities).  

In addition to reviewing the above sources of Information, Mission Hills Community Services District used an alternative method to develop the inventory that the State Water Resources Control Board Division approved on a case-by-case basis. 

Mission Hills CSD used the interpolation method. The Interpolation method. The Interpolation method is used when the water utility can divide its service area into uniform groups, such as neighborhoods or tracts. Each uniform group shares common characteristics, such as the 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.  

Mission Hills CSD created interpolation groups based on tract records and verified a majority of the homes built after January 1, 1986, through construction records or service line replacement reports. All replaced service lines were verified as copper or plastic. No lead or galvanized requiring replacement service lines were identified. 

Mission Hills CSD continues to document service line material information obtained from normal operations, such as service line maintenance or water meter readings, after October 2024 and will update the initial inventory accordingly. 

October 1, 2024