The Missouri Department of Natural Resources has published the Census of Missouri Public Water Systems, 2013. This report provides basic information about the number and type of public water systems in the state, plus information on each system that includes the source of its water, the type of treatment it gives the water, and a chemical analysis of the water that covers 16 inorganic chemicals. The table at right shows the summary data.
The EPA defines a public water system as one that provides water for human consumption to at least 15 service connections or that serves an average of at least 25 people for at least 60 days a year. It classifies public water systems in three categories. Community Systems (CWS) supply water to the same population year-round. Non-Transient Non-Community Water Systems (NTNCWS) supplies water to at least 25 of the same people at least 6 months per year, but not year-round. An example might be a school that has its own water system. A Transient Non-Community Water System (TNCWS) provides water in a place where people do not remain for long periods of time. Examples might include gas stations or campgrounds that have their own water systems.
Groundwater means groundwater that is not directly influenced by the surface water above it. The groundwater is isolated from surface groundwater by thick layers of rock or sediment that filter the ground water before it reaches the groundwater aquifer. Groundwater Under Direct Influence refers to groundwater that is not protected from the surface water above it, and which consequently contains groundwater contaminants, such as insects, microorganisms, algae, or turbidity. This kind of water requires more extensive treatment before it is fit for use.
Most of the water systems in Missouri source their water from groundwater, only a few from ground water under direct influence. However, the source serving the largest population is surface water. Specifically, the Missouri River is the water source for much of the Kansas City and St. Louis metropolitan areas. More than half of Missouri’s population is served by water either from the Missouri River Alluvial Aquifer or water from the river itself.
Census of Missouri Public Water Systems, 2013, Public Drinking Water Banch, Water Quality Program, Missouri Department of Natural Resources, dnr.mo.gov/env/wpp/census.html.