Unregulated Chemicals Requiring Monitoring

The requirements for this monitoring (PDF) (Title 22 of the California Code of Regulations §64450) became effective January 3, 2001. Monitoring for chromium-6 was to have been completed by December 31, 2002, and for other chemicals, by December 31, 2003.

The regulations for unregulated chemicals requiring monitoring were repealed (PDF), effective October 18, 2007.

Perchlorate and hexavalent chromium (chromium-6) are now regulated contaminants.

Overview of monitoring results

Unregulated Chemicals Requiring Monitoring
(22 CCR §64450, repealed October 18, 2007)

Boron 200.7 & 200.8 100
Chromium-6 218.6 1
Dichlorodifluromethane 524.2 & 502.2 0.5
Ethyl tertiary butyl ether 524.2 & 502.2 3
Perchlorate 314 4
Tertiary amyl methyl ether 524.2 & 502.2 3
Tertiary butyl alcohol 524.2 2
Vanadium 200.8 & 200.9 3

*DLR = Detection limit for purposes of reporting, in micrograms per liter (μg/L)
**Methods for 1,2,3-TCP are Continuous Liquid-Liquid Extraction (PDF) - Gas Chromatography / Mass Spectrometry (GC/MS) and Purge and Trap (PDF) - GC/MS

  • NOTE 1: The Department [of Public Health, DPH] extended §64450(b)'s "vulnerable time" to enable collection of one of the two required groundwater samples between May 1 and September 30.
  • NOTE 2: These regulations' adoption occurred before the availability of a method capable of achieving 1,2,3-TCP's DLR of 0.005 μg/L. Some utilities proceeded with monitoring, using laboratory analyses with higher DLRs. Unfortunately, findings of non-detect (ND) with a DLR higher than 0.005 μg/L do not provide the Department with adequate information needed for possible standard setting. The Sanitation and Radiation Laboratory developed an adequate method and some commercial laboratories are able to achieve the 0.005-μg/L DLR with either EPA method 504.1 or 551.1. Therefore, any utility with 1,2,3-TCP findings of ND with reporting levels of 0.010 μg/L or higher should perform follow-up sampling of representative sources for analysis using a method with a 0.005-μg/L DLR.
  • NOTE 3:  For additional information, see Guidance for Unregulated Chemicals Requiring Monitoring (PDF).