Unregulated Contaminants


The fifth Unregulated Contaminant Monitoring Rule (UCMR 5) was published on December 27, 2021. UCMR 5 requires sample collection for 30 chemical contaminants between 2023 and 2025 using analytical methods developed by EPA and consensus organizations. 

Golden State Water routinely monitors and tests for more than 230 contaminants to ensure the water we deliver to customers meets all state and federal drinking water standards. Golden State Water makes water quality information available via annual Consumer Confidence Reports (CCR). As your water provider, we continually invest in water infrastructure, treatment and testing and take great pride in providing you with high-quality, reliable water.

Water quality test results are directly submitted by the State certified laboratory to the State of California’s Division of Drinking Water (DDW) and recorded on the State’s website for full transparency. Click here to view test results on the DDW website.

In order to comply with the UCMR5, Golden State Water will monitor for the following contaminants between 2023 and 2025:

Per- and Polyfluoroalkyl Substances

11-chloroeicosafluoro-3-oxaundecane-1-sulfonic acid (11Cl-PF3OUdS)
9-chlorohexadecafluoro-3-oxanonane-1-sulfonic acid (9Cl-PF3ONS)
4,8-dioxa-3H-perfluorononanoic acid (ADONA)
hexafluoropropylene oxide dimer acid (HFPO DA)
nonafluoro-3,6-dioxaheptanoic acid (NFDHA)
perfluorobutanoic acid (PFBA)
perfluorobutanesulfonic acid (PFBS)
1H,1H, 2H, 2H-perfluorodecane sulfonic acid (8:2FTS)
perfluorodecanoic acid (PFDA)
perfluorododecanoic acid (PFDoA)
perfluoro(2-ethoxyethane)sulfonic acid (PFEESA)
perfluoroheptanesulfonic acid (PFHpS)
perfluoroheptanoic acid (PFHpA)
1H,1H, 2H, 2H-perfluorohexane sulfonic acid (4:2FTS)
perfluorohexanesulfonic acid (PFHxS)
perfluorohexanoic acid (PFHxA)
perfluoro-3-methoxypropanoic acid (PFMPA)
perfluoro-4-methoxybutanoic acid (PFMBA)
perfluorononanoic acid (PFNA)
1H,1H, 2H, 2H-perfluorooctane sulfonic acid (6:2FTS)
perfluorooctanesulfonic acid (PFOS)
perfluorooctanoic acid (PFOA)
perfluoropentanoic acid (PFPeA)
perfluoropentanesulfonic acid (PFPeS)
perfluoroundecanoic acid (PFUnA)
N-ethyl perfluorooctanesulfonamidoacetic acid (NEtFOSAA) 
N-methyl perfluorooctanesulfonamidoacetic acid (NMeFOSAA)
perfluorotetradecanoic acid (PFTA)
perfluorotridecanoic acid (PFTrDA



Customers with questions about UCMR5, drinking water regulations or the drinking water served to their community are asked to contact Golden State Water’s 24-hour Customer Service Center at 800.999.4033 and request to speak with your local Water Quality Engineer.

Resources for Additional Information

U.S. Environmental Protection Agency