Cedar Rapids drinking water at top of 201 treatment systems

CEDAR RAPIDS - The city of Cedar Rapids' drinking water has been deemed the best-tasting drinking water in Iowa.

A new water quality report published in February by the Environmental Working Group in Washington, D.C., found that the drinking water coming from Cedar Rapids Water Division's two water treatment plants ranks best among 201 municipal treatment operations in the nation for the low level of chemicals called haloacetic acids in the treated water.

The city ranks second best of the 201 water systems (after Fresno, Calif.) for the low amount of a second group of chemicals, trihalomethanes, in its treated drinking water.

In the Environmental Working Group's report, Cedar Rapids measured 1.4 parts per billion for total trihalomethane and 0.4 parts per billion for haloacetic acids. By way of comparison, the Des Moines Water Works numbers were 36 and 7 while the private water system in Davenport, which is operated by Iowa American Water Co., had numbers of 92 (the highest of the 201 systems) and 27. The EPA rule sets limits at 80 and 60 for the two groups of chemicals, according to the report.

The environmental group's report notes that the two chemical groups are labeled by the U.S. Environmental Protection Agency as “byproducts” of the water treatment disinfection process, which the environment group prefers to call “toxic trash.”

The name of the report: “Water Treatment Contaminants: Too Much Toxic Trash in American Water.”

Steve Hershner, interim utilities director for the city of Cedar Rapids, took the latest applause for the city's drinking water this week with measured reserve.

“We like the pat on the back, but we always have work to do,” Hershner said. “ ... When I look at a report like this, while I appreciate the results, I don't have blinders on to the fact that they have an agenda.”

Hershner said the two groups of chemicals for which Cedar Rapids is measured at the top among the 201 water systems represent just two lines of two pages of a variety of monitoring results that the city reports in its annual Water Quality Report.

Chemical concerns

The Environmental Working Group report is trying to draw attention to the fact that chlorine used as a disinfectant in water treatment reacts with rotting organic matter like sewage, livestock manure, dead animals and fallen leaves to form toxic chemicals that may be “potentially” harmful to people.

It is a group, though, that is hard to please.

The group's report continues on to say that the water treatment plants like Cedar Rapids' that rely less on free chlorine and more on chloramines - ammonia added with chlorine or ammonia already in the water when chlorine is added - may have “moved the problem and may have complicated it.”

Barb Wagner and Bruce Lyon, both drinking water quality officials with the city of Cedar Rapids, explained this week that the source water for Cedar Rapids' two water treatment plants is harvested by wells from water filtered through sand and gravel at spots along the Cedar River. The water isn't taken directly from the river, but from wells that reach below the river.

This raw water has naturally occurring ammonia, to which chlorine is added at one point in the treatment process to form chloramines. Free chlorine disinfects more effectively, so the city's treatment process holds water in the chloramine stage for a time, which Wagner suggested was the reason that the city ranks so high in certain EPA regulated categories.

Chloramine also is more stable, lasts longer and so helps assure that the city's water meets standards over time and throughout the delivery system, Wagner said.

Lyon said the city of Cedar Rapids can't rely only on chlorine as a disinfectant because the city's raw water already has levels of ammonia in it.

The EPA has not set a standard for chloramines, Hershner said, because the EPA realizes it is an important element in the treatment process in some water supplies.

The Environmental Working Group's discussion of chloramines states that such a treatment process “potentially” could result in levels of an unregulated family of chemical contaminants called iodoacids, though Lyon said that naturally occurring iodide that might make its way into water has a very low probability of occurring.

The nitrosamine family of chemicals also may be byproducts of chloramines, the environmental group's report states, but the EPA has set no standard on these. The city monitors for these chemicals, but in most categories those tests have not detected anything, according to the city's 2011 Water Quality Report.

Treatment process

Hershner, Wagner and Lyon emphasized the Cedar Rapids' water treatment process is multilayered: It features natural filtration from sand and gravel along the river, the addition of lime to kill microorganisms, filtration at the treatment plant, disinfection and then exposure to ultraviolent light to kill bacteria, viruses and protozoa.

The city was the first municipal water system in the state to add ultraviolet light disinfection, which it did in 2010 in anticipation of coming EPA regulatory demands related to viruses and other material.

Megan Murphy, communications coordinator for the city's Utilities Department, said this week that no city that turns raw water into drinking water starts with “this pure, nectar of the gods.” She said all cities must treat the raw water. Waterborne illnesses are almost non-existent in the United States, she said.