CEC Drinking Water Resources

Sample data of public water systems for CECs, specifically for PFAS, is available to view and download using the Water Board’s GeoTracker PFAS Mapping Tool. Additional information is provided on the Water Board’s PFAS website for Drinking Water Resources.

California testing data in public water supply systems is available at the State Water Board’s Public Drinking Water Watch website.

As required by the 1996 Safe Drinking Water Act (SDWA) amendments, the USEPA is required once every five years to collect data for contaminants that are suspected to be present in drinking water and do not have health-based standards set under the SDWA.  A list of no more than 30 unregulated contaminants are tested for by public water systems. During the third (UCMR3) round occurring from 2013-2015 and the fourth (UCMR4) round occurring in 2018-2020, over 10,000 samples were collected in California for CECs. View Additional information about the UCMR sampling rounds and the occurrence data. Sample collection under UCMR 5 will be from January 2023 through December 2025. It will include the required sampling for 29 PFAS compounds and lithium at public water systems.

Current USEPA analytical methods for the analysis of CECs in drinking water are:

• EPA Method 508.1 - Chlorinated Pesticides, Herbicides, and Organohalides in Water by GCECD (51 analytes)
• EPA Method 525.3 - Determination of Semivolatile Organic Chemicals in Drinking Water by Solid Phase Extraction and Capillary Column Gas Chromatography/Mass Spectrometry (GC/MS).  This method includes the identification and quantitation of 125 selected semi-volatile organic analytes in drinking water.
• EPA Method 526 - Determination of Selected Semivolatile Organic Compounds in Drinking Water by Solid Phase Extraction and Capillary Column Gas Chromatography/Mass Spectrometry (GC/MS) (11 analytes)
• EPA Method 527 - Determination of Selected Pesticides and Flame Retardants in Drinking Water by Solid Phase Extraction and Capillary Column Gas Chromatography/Mass Spectrometry (GC/MS) (26 analytes)
• EPA Method 530 - Determination of Select Semivolatile Organic Chemicals in Drinking Water by Solid Phase Extraction and Gas Chromatography/Mass Spectrometry (GC/MS). This method includes the measurement of 4 SVOCs (o-toluidine, quinoline, butylated hydroxyanisole, and dimethipin).
• EPA Method 537.1 - Determination of Selected Per- and Polyfluorinated Alkyl Substances in Drinking Water by Solid Phase Extraction and Liquid Chromatography/Tandem Mass Spectrometry (LC/MS/MS) (18 analytes).
• EPA Method 533 - Determination of Per- and Polyfluoroalkyl Substances in Drinking Water by Isotope Dilution Anion Exchange Solid Phase Extraction and LC/MS/MS (25 analytes).
• EPA Method 539 – Determination of Hormones in Drinking Water by Solid Phase Extraction (SPE) and Liquid Chromatography Electrospray Ionization Tandem Mass Spectrometry (LC-ESI-MS/MS).  This method includes the measurement of 7 hormones.
• EPA Method 542 - Determination of Pharmaceuticals and Personal Care Products in Drinking Water by Solid Phase Extraction and Liquid Chromatography Electrospray Ionization Tandem Mass Spectrometry (LC/ESI-MS/MS). This method includes the measurement of 12 PPCPs.
• EPA Method 544- Determination of Microcystins and Nodularin in Drinking Water by Solid Phase Extraction and Liquid Chromatography/Tandem Mass Spectrometry (LC/MS/MS).  This method includes the measurement of six microcystins and one nodularin (combined intracellular and extracellular).
• EPA Method 545 - Determination of Cylindrospermopsin and Anatoxin-a in Drinking Water by Liquid Chromatography Electrospray Ionization Tandem Mass Spectrometry (LC/ESI-MS/MS). This method includes the measurement of 2 analytes: Anatoxin-a and Cylindrospermopsin.
• EPA Method 546 - Determination of Total Microcystins and Nodularins in Drinking Water and Ambient Water by Adda Enzyme-Linked Immunosorbent Assay (ELISA). The term “Total microcystins and nodularins” is defined as the sum of the congener-independent, intracellular and extracellular microcystin and nodularin that is measurable in a sample. Method 546 measures the total concentration based on detection of a characteristic feature common to microcystin and nodularin congeners.
• EPA Method 556.1, Rev. 1.0 - Determination of Carbonyl Compounds in Drinking Water by Fast Gas Chromatography.  This method includes 14 carbonyl analytes for analysis in finished drinking water and raw source water.

Water Boards SOPs

• Standard Operating Procedures for Extraction and Measurement by Infrared Spectroscopy of Microplastic Particles in Drinking Water: May 27th, 2022 [SWB-MP1-rev1]
• Standard Operating Procedures for Extraction and Measurement by Raman Spectroscopy of Microplastic Particles in Drinking Water: May 27th, 2022 [SWB-MP2-rev1]

Indirect Potable Reuse (IPR) is the planned use of recycled water to replenish drinking water supplies with a suitable environmental barrier. There are two types of IPR projects: Groundwater Replenishment Reuse Projects (GRRP) and Surface Water Source Augmentation Projects (SWSAP). More information is provided here (DW Recycled Water IP | California State Water Resources Control Board)

Direct Potable Reuse is the planned introduction of recycled water either directly into a public drinking water system, or into a raw water supply immediately upstream of a drinking water treatment plant. More information is provided here (Regulating Direct Potable Reuse in California | California State Water Resources Control Board)