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How We Use Water
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Text and illustrations from An Introduction to Michigan's Water Resources, 1987 Michigan State University Institute of Water Research.
Withdrawal uses are categorized as thermoelectric power generation, industrial self-supply, public supply, and irrigation for record-keeping purposes. In Michigan, water used for mining is included in the industrial self-supply category. These four categories account for over 98 percent of the water withdrawn and used in Michigan. The other two percent is generally classified as rural water use such as rural homeowner wells, drinking water for livestock, and dairy sanitation. Most of this water is self-supplied and cannot be readily monitored for reporting purposes.
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Home/Domestic Use
Public Water Supply
Wastewater Treatment
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Home/Domestic Use
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Public water supply systems provide water to homes, schools, and offices, and to industries and businesses that are not self-supplied. Domestic uses in homes include water for drinking, cooking, bathing, brushing teeth, flushing toilets, watering lawns and washing dishes, clothes, and cars. The average Michigan household uses 75 gallons of water per person per day. The average Michigan school uses 15 to 25 gallons of water per student per day.
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Public Water Supply
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The extent of drinking water treatment depends on the source of the water, its characteristics, and the number of people served. All surface water withdrawals for drinking water purposes require treatment prior to distribution whereas groundwater withdrawals may not require treatment. All drinking water must meet federal and state drinking water standards for basic minerals, coliform bacteria, metals, volatile organic compounds, taste, and odor. To meet these standards drinking water may receive treatment, including filtration and chlorination.
Community systems serve more than 25 people for residential uses year round. If necessary, water receives treatment to meet drinking water standards and is monitored regularly by both local and state health departments. Municipal systems are community systems which serve more than 10,000 people, and they almost always receive some form of water treatment. There are more than 11,000 noncommunity systems which are smaller, nonresidential systems, used in rural schools, restaurants, campgrounds, and other facilities. Noncommunity systems almost always use groundwater as their source.
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Wastewater Treatment
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Cities, townships, counties, other local units of government, or sewage disposal districts can all provide waste disposal. Effluent standards are regulated and must be met before a facility discharges effluent to surface waters. Although individual treatment plant methods may vary, wastewater may receive up to three levels of treatment. Solids are removed in primary treatment. Bacteria digest and degrade organic material in secondary treatment. If the particulate and dissolved organic matter are not removed prior to discharge, bacterial breakdown of this material causes oxygen depletion in the receiving water which can adversely affect aquatic life. Some wastewater requires tertiary treatment to meet effluent standards, especially for phosphorus and pathogens. Presently, most tertiary wastewater treatment processes are not capable of removing heavy metals and toxic organic compounds. Discharging these substances into waterways can have significant adverse effects on plants and animals. If an industry produces wastewater containing flammable, explosive or hazardous substances, poisons, or toxics, it is required to pretreat the water before discharge to a public treatment system.
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