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The City of Hopkins is issuing the results of monitoring done on its drinking water for the period from January 1 to December 31, 2004. The purpose of this report is to advance consumers' understanding of drinking water and heighten awareness of the need to protect precious water resources.

Source of Water

The City of Hopkins provides drinking water to its residents from a groundwater source: three wells ranging from 495 to 548 feet deep, that draw water from the Prairie Du Chien-Jordan aquifer.

The water provided to customers may meet drinking water standards, but the Minnesota Department of Health has determined that one or more of the sources of water is potentially susceptible to contamination. If you wish to obtain the entire source water assessment regarding your drinking water, please call 651-215-0800 or 1-800-818-9318 (and press 5) during normal business hours, or view it online.

Call 952-548-6373 if you have questions about the City of Hopkins drinking water or would like information about opportunities for public participation in decisions that may affect the quality of the water.

Results of Monitoring

No contaminants were detected at levels that violated federal drinking water standards. However, some contaminants were detected in trace amounts that were below legal limits. The table that follows shows the contaminants that were detected in trace amounts last year. Some contaminants are sampled less frequently than once a year; as a result, not all contaminants were sampled for in 2004. If any of these contaminants were detected the last time they were sampled for, they are included in the table along with the date that the detection occurred.

Key To Table Abbreviations

  • MCLG (Maximum Contaminant Level Goal)—The level of a contaminant in drinking water below which there is no known or expected risk to health. MCLGs allow for a margin of safety.
  • MCL (Maximum Contaminant Level)—The highest level of a contaminant that is allowed in drinking water. MCLs are set as close to the MCLGs as feasible using the best available treatment technology.
  • MRDL (Maximum Residual Disinfectant Level)
  • MRDLG (Maximum Residual Disinfectant Level Goal)
  • AL (Action Level)—The concentration of a contaminant which, if exceeded, triggers treatment or other requirement which a water system must follow.
  • 90th Percentile Level—This is the value obtained after disregarding 10 percent of the samples taken that had the highest levels. For example, in a situation in which 10 samples were taken, the 90th percentile level is determined by disregarding the highest result, which represents 10 percent of the samples. Note: In situations in which only 5 samples are taken, the average of the two with the highest levels is taken to determine the 90th percentile.
  • pCi/l (PicoCuries per liter)—A measure of radioactivity.
  • ppb (parts per billion)—Can also be expressed as micrograms per liter (ug/l).
  • ppm (parts per million)—Can also be expressed as milligrams per liter (mg/l).
  • N/A (Not applicable)—Does not apply.
Contaminants
(units)
MCLG MCL Level Found Typical Source of Contaminant
Range
2003
Average/Result*
Alpha Emitters (pCi/l) (07/27/2000) 0 15.4 N/A 8.1 Erosion of natural deposits.
Arsenic (ppb) (07/08/2002) 0 50.0 N/A 1.48 Erosion of natural deposits; Runofffrom orchards; Runoff from glass andelectronics production wastes.
Barium (ppm) 2.0 2.0 N/A 0.16 Discharge of drilling wastes; Discharge from metal refineries; Erosion of natural deposits.
Combined Radium (pCi/l) (07/27/2000) 0 5.4 N/A 2.6 Erosion of natural deposits.
Fluoride (ppm) 4.0 4.0 0.84-0.93 0.99 State of Minnesota requires all municipal water systems to add fluoride to the drinking water to promote strong teeth; Erosion of natural deposits; Discharge from fertilizer and aluminum factories.
Nitrate (as Nitrogen) (ppm) 10.0 10.0 nd-0.07 0.07 Run-off from fertilizer use, leaching from septic tanks (sewage), and erosion of natural deposits.
TTHM (Total Trihalomethanes) (ppb) (07/08/2002) N/A 80.0 1.0-1.6 1.23 By-product of drinking water disinfection.
Radon (pCi/l) (11/27/2001) - - N/A 133.0 Erosion of natural deposits.


*This is the value used to determine compliance with federal standards. It sometimes is the highest value detected and sometimes is an average of all the detected values. If it is an average, it may contain sampling results from the previous year.

Radon is a radioactive gas which is naturally occurring in some groundwater. If poses a lung cancer risk when gas is released from water into air (as occurs during showering, bathing, or washing dishes or clothes) and stomach cancer risk when it is ingested. Because radon in indoor air poses a much greater health risk than radon in drinking water, an Alternative Maximum Contaminant Level (AMCL) of 4,000 picoCuries per liter may apply in states that have adopted an Indoor Air Program, which compels citizens, homeowners, schools, and communities to reduce the radon threat from indoor air. For states without such a program, the Maximum Contaminant Level (MCL) of 300 pCi/l may apply. Minnesota plans to adopt an Indoor Air Program once the Radon Rule is finalized.

Contaminants
(units)
MRDLG MRDL Highest & Lowest Monthly Average Highest Quarterly Average Typical Source of Contaminant
Chlorine (ppm) 4.0 4.0 .09-1.0 .093 Water additive used to control microbes.

Contaminants
(units)
MCLG AL 90% Level # Sites Over AL Typical Source of Contaminant
Lead (ppb) N/A 15 7.0 1 out of 30 Corrosion of household plumbing systems, erosion of natural deposits.
Copper (ppm) N/A 13 1.42* 4 out of 20 Corrosion of household plumbing systems, erosion of natural deposits.

 

Some contaminants do not have a Maximum Contaminant Levels established for them. These "unregulated contaminants" are assessed using state standards known as health risk limits to determine if they pose a threat to human health. If unacceptable levels of an unregulated contaminant are found, the response is the same as if an MCL has been exceeded; the water system must inform its customers and take other corrective actions. In the table that follows, are the unregulated contaminants that were detected:

Contaminants (units) Level Found Typical Source of Contaminant
Range 2004 Average/Result*
Sodium (ppm) (7/8/02) N/A 18.0 Erosion of natural deposits.
Sulfate (ppm) (7/8/02) N/A 19.0 Erosion of natural deposits.

Compliance with National Primary Drinking Water Regulations

The sources of drinking water (both tap water and bottled water) include rivers, lakes, streams, ponds, reservoirs, springs, and wells. As water travels over the surface of the land or through the ground, it dissolves naturally occurring minerals and, in some cases, radioactive material, and can pick up substances resulting from the presence of animals or from human activity.

Contaminants that may be present in source water include:

  • Microbial contaminants, such as viruses and bacteria, which may come from sewage treatment plants, septic systems, agricultural livestock operations, and wildlife.
  • Inorganic contaminants, such as salts and metals, which can be naturally occurring or result from urban stormwater runoff, industrial or domestic wastewater discharges, oil and gas production, mining, or farming.
  • Pesticides and herbicides, which may come from a variety of sources such as agriculture, urban stormwater runoff, and residential uses.
  • Organic chemical contaminants, including synthetic and volatile organic chemicals, which are by products of industrial processes and petroleum production, and can also come from gas stations, urban stormwater runoff, and septic systems.
  • Radioactive contaminants, which can be naturally occurring or be the result of oil and gas production and mining activities.

In order to ensure that tap water is safe to drink, the Environmental Protection Agency (EPA) prescribes regulations which limit the amount of certain contaminants in water provided by public water systems. Food and Drug Administration regulations establish limits for contaminants in bottled water which must provide the same protection for public health.

Drinking water, including bottled water, may reasonably be expected to contain at least small amounts of some contaminants. The presence of contaminants does not necessarily indicate that water poses a health risk. More information about contaminants and potential health effects can be obtained by calling the Environmental Protection Agency's Safe Drinking Water Hotline at 1-800-426-4791.

Some people may be more vulnerable to contaminants in drinking water than the general population. Immuno-compromised persons such as persons with cancer undergoing chemotherapy, persons who have undergone organ transplants, people with HIV/AIDS or other immune system disorders, some elderly, and infants can be particularly at risk from infections. These people should seek advice about drinking water from their health care providers. EPA/CDC guidelines on appropriate means to lessen the risk of infection by Cryptosporidium are available from the Safe Drinking Water Hotline at 1-800-426-4791.

For more information on water quality, contact Water and Sewer Superintendent at 952-548-6373.