top of page
  • CSEA

Change to perchlorate testing in drinking water

ATTENTION: Laboratories Who Perform Perchlorate Testing in Drinking Water

The detection limit for purposes of reporting (DLR) will change from 0.004 mg/L to 0.002 mg/L on 1 July 2021, and further decrease to 0.001 mg/L on 1 January 2024. Pursuant to 22 CCR § 64814.00 (a), laboratories who perform perchlorate analysis in drinking water are expected to know the notification, reporting, and record retention requirements for drinking water analysis.

Additionally, in accordance with 22 CCR § 64814.00 (c)(2)(a), laboratories are required to notify a water supplier's designated contact person immediately within 48 hours, when a perchlorate sample result exceeds the maximum contaminant level.

Laboratories should advise their clients and water systems who have questions regarding the revised DLR to contact their local Division of Drinking Water District Office or Local Primacy Agency.

Additional Information

On June 17, 2021, the Office of Administrative Law approved the perchlorate detection limit for purposes of reporting (DLR) regulations adopted by the State Water Board on October 6, 2020. The regulations will take effect on July 1, 2021.

Additional information on the regulation of perchlorate in drinking water can be found by visiting A summary of the rulemaking status and the complete rulemaking file are available at

22 views0 comments


bottom of page