The Power of Information

National Drinking Water Database

Mountain Water Company Utilities - Missoula, MT

Serves 56,335 people


Copper is a naturally occuring metal and drinking water contaminant that enters tap water by corrosion of household plumbing systems and erosion of natural deposits.
This Drinking Water System
Test Days Exceeding Health GuidelinesDefinition of what this is
2 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
39 days
Tests ConductedNumber of individual tests done for this contaminant
133 tests

Testing Summary

Health Limit
Legal Limit

Testing History

-Tested      -Detected      -Over Health Guidelines      -Over Legal Limit*
CopperCopper is a naturally occuring metal and drinking water contaminant that enters tap water by corrosion of household plumbing systems and erosion of natural deposits.124.51 ppb
600 ppb
300 ppb
1000 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 Copper

Health Based Limits for Copper

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.300 ppb
National Secondary Drinking Water RegulationsA National Secondary Drinking Water Regulation is a non-enforceable guideline regarding contaminants that may cause cosmetic effects (such as taste, odor, or color). Some states choose to adopt them as enforceable standards. Source: U.S. Environmental Protection Agency. 1000 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.1300 ppb
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.1300 ppb

Testing Results

Testing DateAverage
Samples taken that dayNumber of Non-DetectsRange of Results
2008-10-290 ppb550 ppb
2008-09-300 ppb110 ppb
2008-08-270 ppb550 ppb
2008-06-230 ppb14140 ppb
2007-10-030 ppb440 ppb
2007-09-180 ppb110 ppb
2007-09-120 ppb330 ppb
2007-09-100 ppb110 ppb
2007-07-12150 ppb10150 ppb
2007-07-03100 ppb10100 ppb
2007-06-29150 ppb10150 ppb
2007-06-2780 ppb1080 ppb
2007-06-21130 ppb3050 to 240 ppb
2007-06-20260 ppb10260 ppb
2007-06-19165 ppb2070 to 260 ppb
2007-06-14260 ppb4090 to 580 ppb
2007-06-13170 ppb10080 to 390 ppb
2007-06-12195 ppb60110 to 500 ppb
2007-03-210 ppb110 ppb
2006-10-040 ppb660 ppb
2006-09-140 ppb220 ppb
2006-08-300 ppb330 ppb
2005-10-100 ppb11110 ppb
2005-09-150 ppb770 ppb
2004-10-280 ppb660 ppb
2004-08-310 ppb330 ppb
2004-08-03215 ppb20160 to 270 ppb
2004-07-30160 ppb10160 ppb
2004-07-29220 ppb10220 ppb
2004-07-23245 ppb20220 to 270 ppb
2004-07-22240 ppb2070 to 410 ppb
2004-07-21166 ppb5070 to 280 ppb
2004-07-20200 ppb9090 to 680 ppb
2004-07-19600 ppb10600 ppb
2004-07-16485 ppb20360 to 610 ppb
2004-07-15195 ppb20120 to 270 ppb
2004-07-14110 ppb10110 ppb
2004-07-12100 ppb10100 ppb
2004-07-11260 ppb10260 ppb