The Power of Information

National Drinking Water Database

San Gabriel Valley WC - Fontana Utilities - Los Angeles, CA

Serves 102,599 people


MTBE (methyl tert-butyl ether) is a fuel additive that had been used as an octane enhancer in unleaded gasoline; it contaminates groundwater due to spillage or leakage at gas stations, and has been banned or scheduled for phaseout in most states.
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
88 days
Tests ConductedNumber of individual tests done for this contaminant
204 tests

Testing Summary

Health Limit
Legal Limit

Testing History

-Tested      -Detected      -Over Health Guidelines      -Over Legal Limit*
MTBEMTBE (methyl tert-butyl ether) is a fuel additive that had been used as an octane enhancer in unleaded gasoline; it contaminates groundwater due to spillage or leakage at gas stations, and has been banned or scheduled for phaseout in most states.0 ppb
0 ppb
13 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 MTBE

Health Based Limits for MTBE

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.13 ppb

Testing Results

Testing DateAverage
Samples taken that dayNumber of Non-DetectsRange of Results
2009-03-100 ppb550 ppb
2009-03-040 ppb330 ppb
2009-02-250 ppb110 ppb
2009-02-180 ppb770 ppb
2009-02-040 ppb550 ppb
2008-10-290 ppb440 ppb
2008-10-220 ppb440 ppb
2008-10-150 ppb220 ppb
2008-08-270 ppb110 ppb
2008-07-080 ppb330 ppb
2008-06-110 ppb110 ppb
2008-05-280 ppb330 ppb
2008-04-090 ppb220 ppb
2008-04-020 ppb110 ppb
2008-03-270 ppb110 ppb
2008-03-190 ppb440 ppb
2008-03-120 ppb660 ppb
2008-03-050 ppb220 ppb
2008-02-120 ppb220 ppb
2008-01-300 ppb110 ppb
2008-01-230 ppb110 ppb
2008-01-030 ppb110 ppb
2007-11-280 ppb220 ppb
2007-10-310 ppb330 ppb
2007-10-240 ppb110 ppb
2007-09-260 ppb110 ppb
2007-05-160 ppb330 ppb
2007-05-090 ppb220 ppb
2007-03-280 ppb220 ppb
2006-12-130 ppb110 ppb
2006-12-080 ppb110 ppb
2006-12-070 ppb220 ppb
2006-11-300 ppb110 ppb
2006-11-270 ppb110 ppb
2006-09-210 ppb110 ppb
2006-09-180 ppb110 ppb
2006-09-150 ppb110 ppb
2006-06-200 ppb110 ppb
2006-06-120 ppb660 ppb
2006-06-080 ppb110 ppb
2006-03-170 ppb110 ppb
2006-03-160 ppb110 ppb
2006-03-150 ppb110 ppb
2005-12-150 ppb440 ppb
2005-12-130 ppb220 ppb
2005-12-010 ppb220 ppb
2005-11-290 ppb220 ppb
2005-09-290 ppb110 ppb
2005-09-220 ppb220 ppb
2005-09-020 ppb110 ppb
2005-07-290 ppb110 ppb
2005-07-280 ppb110 ppb
2005-07-220 ppb110 ppb
2005-07-200 ppb110 ppb
2005-07-190 ppb110 ppb
2005-05-230 ppb110 ppb
2005-05-130 ppb550 ppb
2005-03-290 ppb990 ppb
2005-03-180 ppb220 ppb
2005-03-170 ppb220 ppb
2004-12-090 ppb220 ppb
2004-12-080 ppb660 ppb
2004-08-260 ppb110 ppb
2004-08-250 ppb220 ppb
2004-07-150 ppb110 ppb
2004-06-240 ppb110 ppb
2004-06-230 ppb110 ppb
2004-06-170 ppb330 ppb
2004-04-290 ppb10100 ppb
2004-02-250 ppb440 ppb
2004-02-190 ppb110 ppb
2004-02-030 ppb110 ppb
2004-01-300 ppb220 ppb
2004-01-290 ppb220 ppb
2004-01-280 ppb440 ppb
2004-01-270 ppb220 ppb
2004-01-260 ppb770 ppb
2004-01-230 ppb220 ppb
2004-01-220 ppb220 ppb
2004-01-210 ppb220 ppb
2004-01-140 ppb220 ppb
2004-01-130 ppb220 ppb
2004-01-120 ppb220 ppb
2004-01-090 ppb220 ppb
2004-01-080 ppb220 ppb
2004-01-070 ppb220 ppb
2004-01-060 ppb220 ppb
2004-01-050 ppb220 ppb