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Environmental Health Division
Public Drinking Water Program
The state’s role in administering and enforcing the Safe Drinking Water Act
In Minnesota, we have a safe, reliable, and affordable supply of drinking water that is necessary for health, productivity, and our entire standard of living. But safe drinking water is no accident. It requires the efforts, and teamwork, of many people—including government officials, water utility operators, and the public—to make it possible to maintain the confidence we have in the water from our taps.
Since 1977, the Minnesota Department of Health (MDH) has carried out the provisions of the federal Safe Drinking Water Act (SDWA) in Minnesota. In ensuring a safe drinking water supply, the Drinking Water Program at MDH administers and enforces the SDWA to the nearly 10,000 public water supplies in Minnesota.
Public water supplies
A Public Water Supply is a water system which provides drinking water to persons other than the supplier of the water.
More than 75 percent of Minnesotans get their primary source of drinking water from a public supplier. Even those who have private wells in their home still rely on public suppliers for their drinking water at school, work, church, or while traveling through the state.
Types of Public Water Supply Systems
There are many types of public water supplies, the most prominent being a municipal system, operated by a city to provide water to its citizens. However, mobile home parks and apartment complexes may have their own water supply system for their residents.
In addition to systems that serve residential populations, many public supplies exist to provide water to people outside the home, such as in their schools or businesses.
Another type of public water supply is a transient system, such as a resort or restaurant. Because transient systems serve a constantly changing group of people, they are monitored only for contaminants that pose an immediate health risk, such as bacteria and nitrate.
The other public water supplies-those that provide water to residents, students, or workers-are monitored for contaminants that may cause problems if consumed over a long period of time as well as those that may create immediate health risks.
Treatment of drinking water
The treatment and distribution of water to consumers is the responsibility of the individual public water suppliers.
Threats to drinking water can come from a variety of places. Although pollution from society is the most obvious, there are also a number of naturally occurring materials-ranging from bacteria and viruses to metals to radioactive elements such as radium and radon-present in the environment that can contaminate water sources.
The type of treatment needed for a water supply depends on a variety of factors, including the source of the water.
Surface water sources such as rivers and lakes, which are more susceptible to contamination from animal or human activities, require more complicated treatment. In Minnesota, all surface water suppliers are required to include filtration and disinfection in their treatment process as final barriers of defense against contaminants.
Groundwater in some ways is more insulated from environmental hazards. Also, the ground can serve as a natural filter as water percolates through it to recharge an aquifer. Groundwater can have its own problems, however; it may contain more nitrates from fertilizers and pesticides as well as radioactive elements that occur naturally in the ground.
The Minnesota Department of Health Drinking Water Program
The Minnesota Department of Health stresses assistance and working with water suppliers to assure compliance with SDWA standards, although enforcement through fines and administrative penalty orders can be used when necessary.
Major functions of the MDH Drinking Water Program include:
- Monitoring Drinking Water Quality, which involves the collection and analyses of water samples to determine if disease-causing organisms and toxic chemicals are present. In the event that unacceptable levels of contamination are found, MDH works with the supplier to alert the public and to take corrective action.
- Performing Sanitary Surveys, on-site inspections of a water system’s facilities and operation.
- Establishing Construction Standards, which are set for any kind of water treatment project. MDH’s plan review process ensures conformity with design standards that will enable water systems to meet and remain in compliance with current and future SDWA regulations.
Monitoring: How Often?
MDH may test each public water supply for up to 118 different contaminants. The frequency of testing ranges from monthly to once every nine years, and not all systems are tested for all contaminants. A testing schedule is tailored for each system, based on its vulnerability to various types of contamination.
Factors that affect the testing schedule for a given system include potential contamination sources, whether the system uses wells or surface water, the depth of the wells, geology, and past test results for that system.
Such flexibility in assessing individual systems is both more cost effective as well as just plain more effective.
Monitoring water quality, performing inspections, and establishing design criteria are among the ways MDH works to ensure the safety of drinking water from public suppliers in Minnesota. However, it is critical that both the Minnesota Department of Health and individual public water suppliers remain vigilant in their work to maintain a reliable supply of safe drinking water to the residents of Minnesota. For more information on monitoring, refer to the following Minnesota Department of Health fact sheet: Monitoring and Testing of Drinking Water in Minnesota.
MDH coordinates with other state agencies to determine what types of contaminants a particular water system may be susceptible to. MDH has a working relationship with the Minnesota Pollution Control Agency and their programs which relate to industrial contamination of water supplies. A similar arrangement exists between MDH and the Minnesota Department of Agriculture concerning agricultural chemicals.
For more information about specific contaminants that are monitored in drinking water, refer to Safe Drinking Water Act Standards.