The Power of Information

National Drinking Water Database

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

Serves 17,000,000 people


Perchlorate is a synthetic oxygen additive in solid fuel propellant for rockets, missiles, and fireworks, and is primarily used by the military and the space industry; it may occur naturally in certain imported agricultural fertilizers.
This Drinking Water System
Test Days Exceeding Health GuidelinesDefinition of what this is
1 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
98 days
Tests ConductedNumber of individual tests done for this contaminant
331 tests

Testing Summary

Health Limit
Legal Limit

Testing History

-Tested      -Detected      -Over Health Guidelines      -Over Legal Limit*
PerchloratePerchlorate is a synthetic oxygen additive in solid fuel propellant for rockets, missiles, and fireworks, and is primarily used by the military and the space industry; it may occur naturally in certain imported agricultural fertilizers.0.26 ppb
5.8 ppb
5 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 Perchlorate

Health Based Limits for Perchlorate

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.5 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.6 ppb

Testing Results

Testing DateAverage
Samples taken that dayNumber of Non-DetectsRange of Results
2009-01-120 ppb660 ppb
2009-01-050.6 ppb210 to 1.2 ppb
2008-10-130 ppb660 ppb
2008-10-060.65 ppb210 to 1.3 ppb
2008-07-140 ppb660 ppb
2008-07-072.1 ppb102.1 ppb
2008-04-140 ppb660 ppb
2008-04-090 ppb110 ppb
2008-04-072.2 ppb102.2 ppb
2008-01-300 ppb660 ppb
2008-01-071.5 ppb101.5 ppb
2007-10-310 ppb660 ppb
2007-10-010 ppb220 ppb
2007-07-310 ppb660 ppb
2007-07-020 ppb220 ppb
2007-04-300 ppb660 ppb
2007-04-020 ppb220 ppb
2007-01-310 ppb660 ppb
2007-01-030 ppb110 ppb
2006-12-270 ppb660 ppb
2006-12-040 ppb220 ppb
2006-11-290 ppb440 ppb
2006-11-280 ppb110 ppb
2006-11-060 ppb110 ppb
2006-11-010 ppb110 ppb
2006-10-310 ppb550 ppb
2006-10-020.9 ppb210 to 1.8 ppb
2006-09-270 ppb660 ppb
2006-09-050 ppb220 ppb
2006-09-010 ppb330 ppb
2006-08-310 ppb220 ppb
2006-08-070 ppb220 ppb
2006-07-310 ppb660 ppb
2006-07-050 ppb110 ppb
2006-06-300 ppb660 ppb
2006-06-050 ppb220 ppb
2006-05-310 ppb660 ppb
2006-05-011.1 ppb210 to 2.2 ppb
2006-04-300 ppb660 ppb
2006-04-030 ppb220 ppb
2006-03-300 ppb660 ppb
2006-03-060 ppb220 ppb
2006-02-280 ppb660 ppb
2006-02-060 ppb110 ppb
2006-01-310 ppb660 ppb
2006-01-030 ppb220 ppb
2005-12-300 ppb660 ppb
2005-12-050 ppb220 ppb
2005-11-300 ppb660 ppb
2005-11-070 ppb220 ppb
2005-10-310 ppb660 ppb
2005-10-030 ppb110 ppb
2005-09-300 ppb550 ppb
2005-09-290 ppb110 ppb
2005-09-061.05 ppb210 to 2.1 ppb
2005-08-310 ppb660 ppb
2005-08-010 ppb110 ppb
2005-07-310 ppb660 ppb
2005-07-050 ppb110 ppb
2005-06-300 ppb660 ppb
2005-06-060 ppb110 ppb
2005-05-310 ppb660 ppb
2005-05-020 ppb110 ppb
2005-04-300 ppb660 ppb
2005-04-110 ppb110 ppb
2005-03-300 ppb660 ppb
2005-03-070 ppb110 ppb
2005-02-280 ppb660 ppb
2005-02-070 ppb110 ppb
2005-01-310 ppb660 ppb
2005-01-030 ppb110 ppb
2004-12-310 ppb550 ppb
2004-12-280 ppb110 ppb
2004-12-060 ppb110 ppb
2004-11-300 ppb660 ppb
2004-11-010 ppb110 ppb
2004-10-310 ppb550 ppb
2004-10-290 ppb110 ppb
2004-10-040 ppb110 ppb
2004-09-300 ppb660 ppb
2004-09-070 ppb110 ppb
2004-08-310 ppb660 ppb
2004-08-020 ppb110 ppb
2004-07-310 ppb660 ppb
2004-07-060 ppb110 ppb
2004-06-300 ppb660 ppb
2004-06-070 ppb110 ppb
2004-05-310 ppb660 ppb
2004-05-034.7 ppb104.7 ppb
2004-04-300 ppb660 ppb
2004-04-055.8 ppb105.8 ppb
2004-03-310 ppb660 ppb
2004-03-014.5 ppb104.5 ppb
2004-02-290 ppb660 ppb
2004-02-020 ppb110 ppb
2004-01-310 ppb550 ppb
2004-01-300 ppb110 ppb
2004-01-050 ppb110 ppb