The Power of Information

National Drinking Water Database

Joliet Utilities - Joliet, IL

Serves 145,000 people


Diquat is a non-selective herbicide and dessicant used extensively for control of crop and aquatic weeds; it may cause cataracts.
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
23 days
Tests ConductedNumber of individual tests done for this contaminant
65 tests

Testing Summary

Health Limit
Legal Limit

Testing History

-Tested      -Detected      -Over Health Guidelines      -Over Legal Limit*
DiquatDiquat is a non-selective herbicide and dessicant used extensively for control of crop and aquatic weeds; it may cause cataracts.0 ppb
0 ppb
15 ppb
20 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 Diquat

Health Based Limits for Diquat

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.15 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.20 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.20 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.20 ppb

Testing Results

Testing DateAverage
Samples taken that dayNumber of Non-DetectsRange of Results
2009-02-180 ppb440 ppb
2009-02-110 ppb660 ppb
2008-10-280 ppb110 ppb
2008-08-110 ppb110 ppb
2007-03-270 ppb110 ppb
2006-11-270 ppb220 ppb
2006-08-140 ppb220 ppb
2006-04-110 ppb550 ppb
2006-04-100 ppb550 ppb
2006-02-010 ppb330 ppb
2006-01-310 ppb550 ppb
2006-01-240 ppb220 ppb
2005-10-250 ppb110 ppb
2005-10-180 ppb440 ppb
2005-07-260 ppb330 ppb
2005-05-240 ppb330 ppb
2005-02-150 ppb330 ppb
2004-11-290 ppb330 ppb
2004-08-170 ppb330 ppb
2004-05-250 ppb110 ppb
2004-05-240 ppb330 ppb
2004-02-180 ppb110 ppb
2004-02-170 ppb330 ppb