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Environmental Health Division
Safe Drinking Water Act Standards
This page contains information about the types of contaminants that are regulated in drinking water. For more information about specific contaminants, visit A-Z List of Contaminants in Drinking Water.
Drinking water regulations
The Minnesota Department of Health enforces the federal Safe Drinking Water Act. The Safe Drinking Water Act contains National Primary Drinking Water Regulations, which are legally enforceable standards and treatment techniques that apply to public water systems.
The Safe Drinking Water Act defines a contaminant as anything other than water molecules. Drinking water typically contains at least small amounts of some contaminants. The presence of contaminants does not necessarily mean that the water poses a health risk. If a contaminant is present above a particular level, then it may cause harmful health effects. Safe Drinking Water Act standards and treatment techniques protect public health by limiting the levels of contaminants in drinking water.
More information is available at Basics of Monitoring and Testing of Drinking Water in Minnesota.
Types of contaminants regulated in drinking water
Microorganisms—including bacteria, protozoa, and viruses—are among the oldest health threats to drinking water quality. They are responsible for most waterborne diseases and can cause immediate health effects.
Because of technological limits or other factors, it is not possible to reliably test for some microorganisms. Instead, public water systems are required to use specific Treatment Techniques (TT) that are designed to remove these contaminants from the water.
To learn more about the microorganisms that we regulate, visit National Primary Drinking Water Regulations - Microorganisms.
Public water systems may use disinfectants to kill or inactivate harmful microorganisms. The use of disinfectants has resulted in the virtual elimination of waterborne diseases such as cholera, typhoid, dysentery, and hepatitis A.
The most common method of disinfection is through the addition of chlorine to drinking water supplies. Chlorine effectively kills waterborne bacteria and viruses and continues to keep the water safe as it travels from the treatment plant to the consumer's tap.
To learn more about the disinfectants that we regulate, visit EPA’s National Primary Drinking Water Regulations - Disinfectants.
To learn more about drinking water disinfection and disinfection byproducts, visit Disinfection and Disinfection Byproducts. To learn more about drinking water chlorination, visit Drinking Water Chlorination: Frequently Asked Questions.
Though disinfectants have been a literal lifesaver with regard to drinking water, they also have the potential to form byproducts that can have harmful health effects. Disinfection byproducts form when disinfectants react with organic material, like decomposing plants.
Disinfection byproducts can cause negative health effects after long-term exposure at levels above federal standards. Water systems work to minimize the formation of disinfection byproducts without compromising public health protection from disinfection.
To learn more about the disinfection byproducts that we regulate, visit EPA’s National Primary Drinking Water Regulations – Disinfection Byproducts.
To learn more about drinking water disinfection and disinfection byproducts, visit Disinfection and Disinfection Byproducts.
Organic chemicals are compounds that contain carbon. They include volatile organic compounds (VOCs) and synthetic organic compounds (SOCs). Examples include pesticides and industrial and commercial products, including degreasers, paints, and petroleum products. Organic chemicals in drinking water can cause negative health effects after long-term exposure at levels above federal standards.
To learn more about the organic chemicals that we regulate, visit EPA’s National Primary Drinking Water Regulations – Organic Chemicals.
Inorganic chemicals are metals, salts, and other compounds that typically do not contain carbon. Inorganic chemicals occur naturally and can also come from human activities.
Nitrate and nitrite can cause immediate, negative health effects if consumed at levels above the federal standard. Other inorganic chemicals can cause negative health effects after long-term exposure at levels above federal standards.
Lead and copper are inorganic compounds that are different because they are rarely found in the sources of our drinking water. Usually, these contaminants enter the water as it passes through pipes and plumbing systems.
Fluoride is nature's cavity fighter, with small amounts present naturally in many drinking water sources. Since studies show that optimal fluoride levels in drinking water benefit public health, municipal community water systems adjust the level of fluoride in the water to optimal levels. If the water contains fluoride above the standard, it can result in negative effects, such as tooth discoloration and skeletal fluorosis, a bone disease.
To learn more about the inorganic chemicals that we regulate, visit EPA’s National Primary Drinking Water Regulations – Inorganic Chemicals.
Occurrences of radionuclides in Minnesota drinking water are from natural sources within aquifers. These contaminants can cause negative health effects after long-term exposure at levels above federal standards. Radionuclides are also known as radiological contaminants.
To learn more about the radionuclides that we regulate, visit EPA’s National Primary Drinking Water Regulations - Radionuclides.