The Power of Information

National Drinking Water Database

Metropolitan Water District of Southern California Utilities - Los Angeles, CA

Serves 17,000,000 people


Hexachlorocyclopentadiene is an industrial pollutant discharged from chemical factories.
This Drinking Water System
Test Days Exceeding Health GuidelinesDefinition of what this is
0 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
11 days
Tests ConductedNumber of individual tests done for this contaminant
41 tests

Testing Summary

Health Limit
Legal Limit

Testing History

-Tested      -Detected      -Over Health Guidelines      -Over Legal Limit*
HexachlorocyclopentadieneHexachlorocyclopentadiene is an industrial pollutant discharged from chemical factories.0 ppb
0 ppb
40 ppb
50 ppb
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 Hexachlorocyclopentadiene

Health Based Limits for Hexachlorocyclopentadiene

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.40 ppb
Maximum Contaminant Limit (MCL)The enforceable standard which defines the highest level of a contaminant that is allowed in drinking water. MCLs are set as close to health-based limits (Maximum Contaminant Level Goals, or MCLGs) as feasible using the best available analytical and treatment technologies and taking cost into consideration. Source: U.S. Environmental Protection Agency.50 ppb
Maximum Contaminant Limit Goal (MCLG)A non-enforceable health goal that is set at a level at which no known or anticipated adverse effect on the health of persons occurs and which allows an adequate margin of safety. Source: U.S. Environmental Protection Agency.50 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.50 ppb
Drinking Water Equivalent LevelA lifetime exposure concentration protective of adverse, noncarcinogenic health effects, that assumes all of the exposure to a contaminant is from drinking water. Source: U.S. Environmental Protection Agency.200 ppb

Testing Results

Testing DateAverage
Samples taken that dayNumber of Non-DetectsRange of Results
2008-05-050 ppb660 ppb
2007-02-060 ppb220 ppb
2007-02-050 ppb550 ppb
2006-11-150 ppb110 ppb
2006-11-130 ppb440 ppb
2006-11-060 ppb330 ppb
2006-05-010 ppb770 ppb
2005-10-100 ppb110 ppb
2005-10-040 ppb110 ppb
2005-10-030 ppb440 ppb
2004-08-020 ppb770 ppb