Fact Check: Quality of Iowa's drinking water

Are polluted waterways causing a nitrate surge in Iowa?

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Water quality is a funding priority for the Iowa Department of Agriculture this legislative session. We're checking the claim that, because of runoff from farms, Iowa has more than 600 polluted rivers, lakes and streams, causing a nitrate surge in our drinking water.

Source of claim

Citizens for a Healthy Iowa

Here's a clip of the group's TV advertisement on Iowa's drinking water:

According to the Iowa DNR's 2012 List of Impaired Waters Fact Sheet, there are 630 lakes, rivers and streams in Iowa. Of the 630 impaired bodies of water, 480 need a water quality improvement plan. The other 150 don't need a plan because one already has been prepared by Iowa DNR and approved  by the  U.S. Environmental Protection Agency, or the impairment comes from a non-pollutant stressor, such as habitat degradation or stream channelization.

The fact sheet also identifies the most common causes of pollution in Iowa waters. According to the data, a total of 606 impairments were found in Iowa's streams and rivers in 2012. Bacteria was the most commonly identified impairment, responsible for 277 of the total impairments, and nitrates were identified as an impairment in 6 of the total 606 river and stream impairments.

In lake and flood control reservoirs, a total of 240 impairments were identified. Algae caused the most impairments — with 62 of the total 240— and nitrates contributed to one of the total 240 impairments.

As required by the Safe Drinking Water Act, states are required to prepare an annual report. Iowa's 2012 compliance report says 6 percent of the state's population is served by a public water supply that violated a health-based standard at some time. Of that 6 percent, 48 percent were polluted by bacteria, and 9.3 percent of the violations were for nitrate nitrogen. No waterborne diseases or deaths were reported from Iowa public water supply systems in 2012.

The report said the presence of bacteria, including E.Coli, in drinking water is usually associated with sewage or animal waste. Pollutants such as soil, bacteria and nutrients from farm fertilizers and manure often land in steams and lakes as a result of runoff. However, DNR officials said it's often hard to tell exactly what the source of a particular pollutant is in a particular stream.

When chronic contaminants are identified in a water source, the community is warned of the problem. The community then works with the state to determine the best way to solve the pollution issue to make sure the water meets federal standards.


Though there indeed are more than 600 polluted bodies of water in Iowa according to the most recent information available, data shows nitrates are not the most commonly detected pollutant. However, bacteria is the most commonly detected pollutant and that bacteria can sometimes come from runoff. We rate this claim mostly true.

















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