Drinking Water

glass of watergo to the data buttonWater is an important part of our lives. Having a safe drinking water supply is important to the public’s health. Contaminants in drinking water could affect many people because we use water every day.

Some contaminants in water are naturally found in the environment and include bacteria, parasites, and arsenic. Other contaminants are human made, such as industrial waste and fertilizers. Contaminants in drinking water can be a threat to human health, especially the health of young children, the elderly, and pregnant women. Local, state, and federal drinking water protection programs play a key role in providing safe drinking water.

How is drinking water monitored in Michigan?

The U.S. Environmental Protection Agency (EPA) sets regulations and standards for monitoring and treating drinking water through the Safe Drinking Water Act. The Michigan Department of Environment, Great Lakes, and Energy (EGLE) enforces these standards through the Michigan Safe Drinking Water Act. About 75% of Michigan residents get their water from sources that are regulated through these Acts.

About 25% of Michigan residents get their water from small water supplies such as private wells. Private wells that serve fewer than 25 people are not regulated by the Safe Drinking Water Act. However, the EGLE also investigates drinking water well contamination, oversees the water well drilling industry, and oversees remedial activities where groundwater contamination has affected private drinking water wells. Local health departments administer EGLE programs for private wells and some other types of water supply systems.

What health problems could be caused by drinking water contaminants?

Water quality standards and monitoring requirements are in place for more than 90 biological and chemical contaminants. The presence of contaminants in drinking water is not necessarily a health risk, but exposure to contaminants in drinking water can cause health problems. These problems can be short-term such as nausea, vomiting, and diarrhea. Some diseases, such as cancer, or neurological disorders, can be caused by exposure to contaminants over a longer period time.

The risk of developing a drinking-water related health problem depends on many factors:

  • The specific contaminant

  • How much of the contaminant a person is exposed to

  • How a person comes into contact with the water, for example, drinking or showering

  • Individual factors such as body size, age, and health conditions.

Who is most at risk?

Some people are more sensitive to contaminants in water. They can include:

  • Elderly people

  • Pregnant women

  • People who already have serious health conditions

  • People with poor nutrition

What can you do to avoid harm from drinking water contaminants?

There are no requirements to routinely test the water of a private well. However, if you get your water from a private well, you should have your water tested to be sure it is safe. You will need to pay a fee for having your well water tested. Contact your local health department for information about having your well water tested.

If you are on a community water supply, read the Consumer Confidence Report your water supplier sends you each year. It gives you information about your supplier and if it had violations of drinking water regulations during the year. Every community water supplier is required to provide the report by July 1 of each year to all of its customers.

Help reduce water pollution by reducing the amount of pesticides and fertilizers you use, and take steps to keep pollutants away from storm drains.

If you have a septic system, be sure to maintain it in order to keep biological contaminants out of your drinking water and the environment.

What drinking water data are available on the MiTracking data portal?

Data are available for these contaminants.

The data can tell us:

  • Distribution of number of Community Water Systems (CWS) by average chemical concentrations of these by year and/or quarter

  • Distribution of number of CWS by maximum chemical concentrations by year

  • Distribution of number of people served by CWS by mean chemical concentrations by year and/or quarter

  • Distribution of number of people served by CWS by maximum chemical concentrations by year

  • Average concentration at CWS-level

However, the data cannot tell us:

  • Differences in how much disinfection biproducts (DBPs)a person might be exposed to throughout the year because

    • levels of DBPs change with the seasons,

    • sampling schedules vary among community water systems, and

    • levels of DBPs increase or decrease depending on how far they have traveled through the water distribution system.

  • Information about drinking water from private wells or public water systems that are not used the entire year

  • How much contaminant an individual person was exposed to

  • If contaminants in drinking water caused an individual’s illness

Learn More

Centers for Disease Control and Prevention

Healthy Drinking Water

Community Water Monitoring in the U.S.

Private Ground Water Wells

Environmental Protection Agency

How to Identify Lead Free Plumbing

Safe Drinking Water Act

Table of Regulated Drinking Water Contaminants

Protecting Your Drinking Water

Bottled Water Basics

Michigan Department of Environment, Great Lakes, and Energy (EGLE)


Michigan Safe Drinking Water Act 399

Your New Water Well

A Consumer’s Guide to Hiring a Well Contractor

How to Have Your Water Tested by the DEQ Drinking Water Lab

National Groundwater Association

Consumer Information Sheets

State of Michigan

Flint Water


Private Well Class

Well Owner Information


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