The purpose of fresh water treatment is to produce clean water that is safe to drink and palatable. Source ground water in the Twin Cities is abundant and clean and very hard. The Safe Drinking Water Act that the Environmental Protection Agency (EPA) authored has set standards that all of the water utilities in the United States follow. The standards require extensive testing that the Minnesota Department of Health coordinates with the water utilities and monitors the results so that the drinking water is as safe it can be all over the country. The water utilities constantly test the treated water for chemical composition and bacterial contamination and submit to regular inspections by the Minnesota Department of Health.
The city adds chlorine to control taste and odor and keep the water system bacterially clean. Corrosion control in the water system is handled by the addition of LPC-9 Corrosion Inhibitor, it creates barrier inside the plumbing that reduces the transfer of lead from the solder, and copper from the pipes in to the drinking water systems.
Fluoride is added to the water to help prevent tooth decay, the level of fluoride is kept at 1.0 to 1.2 Parts per million as mandated by The Minnesota Department of Health requirements.
The City's water is 17 to 18 grains of hardness, and has less than .03 parts per million of iron after filtering.
For more information on water quality, contact Water and Sewer Superintendent at 952-548-6373.
Drinking Water Quality In Hopkins (9/18/07)
Recent StarTribune newspaper articles have been focusing on the troubling problem of contaminated ground water that impacts several Twin Cities area communities. Fortunately, the City of Hopkins drinking water is not contaminated and water tested from our three municipal wells have only shown very minute, trace amounts of one substance common with the groundwater contamination plumes illustrated in the newspaper. The City's drinking water is well within all safe drinking water standards.
The City of Hopkins obtains its drinking water from three municipal wells each about 500' deep and extending into the Prairie Du Chien-Jordan groundwater aquifer. A water treatment plant treats and filters the well water to reduce iron and manganese concentrations, and then chlorinates and fluoridates for disinfection and dental care. The City's public water supply system has always remained in full compliance with all state and federal drinking water regulations. Water samples are routinely collected and analyzed by the Minnesota Department of Health as required under the Minnesota Public Water Supply Program.
The newspaper articles include diagrams that show two groundwater contamination plumes that extend into the city of Hopkins. These are the Reilly Tar & Chemical plume and the "Edina plume." Back in the 1980s when the impacts of the Reilly Tar & Chemical contamination plume came to light, the Minnesota Department of Health began a 10-year annual testing cycle on Hopkins municipal well water. This testing confirmed that the PAH contaminants associated with the Reilly plume were not migrating "upstream" to the Hopkins wells. This water testing also included vinyl chloride, the contaminant found in the "Edina plume" - test results showed that Hopkins well water was not contaminated with this substance. In 2004, the City of Hopkins participated in well water testing for a National Water Quality Assessment Program of the U.S. Geological Survey. These test results confirmed that there were no contaminants above detection limits, including vinyl chloride, in the well water. Results of periodic MDH water testing (last test date was March 2007) for volatile organic compounds, including vinyl chloride, have shown only extremely low concentrations of one substance common with the groundwater contamination plumes: cis-1.2-dichloroethene. This concentration is 1.2 - 1.5 parts per billion (ppb) or more than 50 times lower than the drinking water standard of 70 ppb and requires no action by the city.
In order to prevent future contamination of Hopkins' municipal wells, the City recently completed a wellhead protection plan that will help City staff guard against undesirable land use or existing public or private well activity that could affect our invaluable groundwater aquifer.
Questions may be directed to Water and Sewer Superintendent at 952-548-6373 or Public Works Director at 952-548-6350.