The fourth Unregulated Contaminant Monitoring Rule (UCMR4) was published in the Federal Register by the United States Environmental Protection Agency (USEPA) in December 2016, requiring that all large drinking water systems serving more than 10,000 customers—as well as 800 randomly selected small drinking water systems serving 25-10,000 customers—monitor for 30 unregulated chemical contaminants between 2018 and 2020. USEPA will use the data from UCMR4 to determine future regulations to protect public health.

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 UCMR4, Golden State Water will monitor for the following contaminants between 2018 and 2020:

Cyanotoxins
Total Microcystin
Microcystin-LA
Microcystin-LF
Microcystin-LR
Microcystin-LY
Microcystin-RR
Microcystin-YR
Nodularin
Anatoxin-a
Cylindrospermopsin

Metals
Germanium
Manganese

8 Pesticides and One Pesticide Manufacturing Byproduct
Alpha-Hexachlorocyclohexane
Chlorpyrifos
Dimethipin
Ethoprop
Oxyfluorfen
Profenofos
Tebuconazole
Total Permethrin (cis & trans)
Tribufos

Three Brominated Haloacetic Acid (HAA) Groups
HAA5
HAA6Br
HAA9

Three Alcohols
1-Butanol
2-Methoxyethanol
2-Propen-1-ol

Three Other Semivolatile Chemicals
Butylated Hydroxyanisole
o-Toluidine
Quinolone

Indicators
Total Organic Carbon (TOC)
Bromide

Customers with questions about UCMR4, 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