The Power of Information

National Drinking Water Database

Pomona - City, Water Dept. Utilities - Los Angeles, CA

Serves 156,500 people


n-Nitrosodimethylamine is a carcinogenic water contaminant released from various industrial processes; it also forms in drinking water as disinfection byproduct of chloramination and from agricultural runoff.
This Drinking Water System
Test Days Exceeding Health GuidelinesDefinition of what this is
67 days
Test Days Exceeding Legal LimitsNumber of days in which the samples taken in that day exceed the Maximum Contaminant Level (Depending on the contaminant and its MCL, that may or may not trigger an MCL violation. Some MCLs are based on averages spanning several months to a year)
0 days
Test DaysNumber of days in which this chemical has reported results in the data we received from the State
86 days
Tests ConductedNumber of individual tests done for this contaminant
168 tests

Testing Summary

Health Limit
Legal Limit

Testing History

-Tested      -Detected      -Over Health Guidelines      -Over Legal Limit*
n-Nitrosodimethylaminen-Nitrosodimethylamine is a carcinogenic water contaminant released from various industrial processes; it also forms in drinking water as disinfection byproduct of chloramination and from agricultural runoff.0.02 ppb
0.26 ppb
<0.01 ppb
Legal at any levelThis is the Federal Limit. State Limits may be lower.
NOTE: Each dot in the above graph represents one month.
* Water utilities are noted as exceeding the legal limit if any test is above the maximum contaminant level (MCL). Most MCLs are based on annual averages so exceeding the MCL for one test does not necessarily indicate that the system is out of compliance.

Health Based and Legal Limits for n-Nitrosodimethylamine

Health Based Limits for n-Nitrosodimethylamine

EPA Human Health Water Quality CriteriaWater quality criteria set by the US EPA provide guidance for states and tribes authorized to establish water quality standards under the Clean Water Act (CWA) to protect human health. These are non-enforceable standards based upon exposure by both drinking water and the contribution of water contamination to other consumed foods. Source: U.S. Environmental Protection Agency.<0.01 ppb
Health-Based Screening LevelA benchmark concentration of contaminants in water that may be of potential concern for human health, if exceeded. For noncarcinogens, the HBSL represents the contaminant concentration in drinking water that is not expected to cause any adverse effects over a lifetime of exposure. For carcinogens, the HBSL range represents the contaminant concentration in drinking water that corresponds to an excess estimated lifetime cancer risk of 1 chance in 1 million to 1 chance in 10 thousand. Source: U.S. Geological Survey.<0.01 ppb-0.07 ppb
California Public Health GoalsDefined by the State of California Office of Environmental Health Hazard Assessment (OEHHA) as the level of contaminant that is allowed in drinking water. For acutely toxic substances, levels are set at which scientific evidence indicates that no known or anticipated adverse effects on health will occur, plus an adequate margin-of safety. PHGs for carcinogens or other substances which can cause chronic disease shall be based solely on health effects without regard to cost impacts and shall be set at levels which OEHHA has determined do not pose any significant risk to health.<0.01 ppb

Testing Results

Testing DateAverage
Samples taken that dayNumber of Non-DetectsRange of Results
2009-03-020 ppb220 ppb
2009-02-230 ppb110 ppb
2009-02-200 ppb110 ppb
2009-02-030 ppb220 ppb
2009-01-050 ppb440 ppb
2008-12-170 ppb110 ppb
2008-12-010 ppb110 ppb
2008-11-200 ppb110 ppb
2008-11-100 ppb220 ppb
2008-10-300 ppb110 ppb
2008-09-050 ppb440 ppb
2008-08-260 ppb220 ppb
2008-06-02<0.01 ppb20< .01 to 0.005 ppb
2008-05-240 ppb880 ppb
2008-05-050.02 ppb200.02 ppb
2008-04-010.01 ppb200.01 to 0.02 ppb
2008-03-030.01 ppb200.01 ppb
2008-02-040.01 ppb200.01 ppb
2008-01-070.01 ppb40<0.01 to 0.03 ppb
2007-12-03<0.01 ppb20< .01 to 0.008 ppb
2007-11-06<0.01 ppb20< .01 to 0.009 ppb
2007-10-170.02 ppb100.02 ppb
2007-10-030.02 ppb200.02 to 0.03 ppb
2007-09-050 ppb220 ppb
2007-08-14<0.01 ppb20< .01 to 0.005 ppb
2007-07-03<0.01 ppb20< .01 to 0.004 ppb
2007-06-06<0.01 ppb20< .01 to 0.004 ppb
2007-05-02<0.01 ppb10< .01 to 0.002 ppb
2007-05-01<0.01 ppb10< .01 to 0.003 ppb
2007-04-040.04 ppb200.01 to 0.06 ppb
2007-03-270.03 ppb100.03 ppb
2007-03-060.26 ppb200.24 to 0.28 ppb
2007-02-060.01 ppb200.01 ppb
2007-01-030.01 ppb410 to 0.02 ppb
2006-12-140 ppb110 ppb
2006-12-050.04 ppb200.01 to 0.06 ppb
2006-11-070.12 ppb200.05 to 0.19 ppb
2006-10-03<0.01 ppb20<0.01 to 0.01 ppb
2006-09-060.01 ppb20<0.01 to 0.01 ppb
2006-08-150.05 ppb100.05 ppb
2006-08-020.11 ppb200.06 to 0.15 ppb
2006-07-050.03 ppb200.01 to 0.04 ppb
2006-06-07<0.01 ppb30<0.01 to 0.01 ppb
2006-05-100 ppb110 ppb
2006-05-020.11 ppb200.06 to 0.15 ppb
2006-04-04<0.01 ppb30< .01 to 0.008 ppb
2006-03-070.01 ppb200.01 to 0.02 ppb
2006-02-010.01 ppb200.01 to 0.02 ppb
2006-01-04<0.01 ppb410 to 0.01 ppb
2005-12-060.01 ppb20<0.01 to 0.01 ppb
2005-11-020.01 ppb200.01 ppb
2005-11-010 ppb110 ppb
2005-10-26<0.01 ppb20< .01 to 0.006 ppb
2005-10-19<0.01 ppb20<0.01 to 0.01 ppb
2005-10-070 ppb110 ppb
2005-10-040.02 ppb200.01 to 0.03 ppb
2005-09-130.06 ppb200.03 to 0.1 ppb
2005-09-06<0.01 ppb20< .01 to 0.008 ppb
2005-08-310.01 ppb200.01 to 0.02 ppb
2005-08-22<0.01 ppb20< .01 to 0.007 ppb
2005-08-180.01 ppb20<0.01 to 0.02 ppb
2005-08-12<0.01 ppb310 to 0.01 ppb
2005-08-010.02 ppb200.01 to 0.03 ppb
2005-07-290.02 ppb420 to 0.06 ppb
2005-07-270.01 ppb20<0.01 to 0.02 ppb
2005-07-140.03 ppb200.01 to 0.05 ppb
2005-06-14<0.01 ppb20<0.01 to 0.01 ppb
2005-05-18<0.01 ppb310 to 0.01 ppb
2005-04-280.01 ppb200.01 ppb
2005-04-190 ppb110 ppb
2005-04-070.02 ppb100.02 ppb
2005-03-03<0.01 ppb20<0.01 to 0.01 ppb
2005-02-030.01 ppb100.01 ppb
2005-01-20<0.01 ppb310 to 0.02 ppb
2005-01-06<0.01 ppb10< .01 to 0.009 ppb
2004-12-030.01 ppb100.01 ppb
2004-11-050.01 ppb100.01 ppb
2004-10-070.01 ppb100.01 ppb
2004-09-090.01 ppb100.01 ppb
2004-07-07<0.01 ppb10< .01 to 0.007 ppb
2004-06-03<0.01 ppb10< .01 to 0.009 ppb
2004-05-06<0.01 ppb10< .01 to 0.008 ppb
2004-04-09<0.01 ppb10< .01 to 0.008 ppb
2004-03-04<0.01 ppb10< .01 to 0.009 ppb
2004-02-050.01 ppb100.01 ppb
2004-01-080.01 ppb410 to 0.02 ppb