This map draws on data collected from the California State Water Resources Control Board (from Jan. 1, 2017 to Sept. 24, 2020) and several districts that conducted their own water testing after 2020, including San Bruno Park Elementary in San Mateo (from Oct. 28, 2022 to July 21, 2023), La Mesa-Spring Valley in San Diego (from Sept. 12, 2023 to Oct. 17, 2023)，Castro Valley Unified in Alameda (from Nov. 13-17, 2023), Encinitas Union Elementary in San Diego (from April 12-26, 2023)，Oakland Unified in Alameda (from March 2022 to September 2024), San Francisco Unified (from May 7, 2022 to Nov. 11, 2023).
Compared to the map EdSource published in 2018, this map has added active lead levels at school sites as well as the number of fixtures that have been tested. California law requires schools to take action if lead levels in their drinking water exceed 15 parts per billion (ppb). Data is updated as of June 27, 2024.
Note: Some of the data records may not be updated regularly on school district websites. To confirm results of lead testing, please contact your local school directly.