Residents of DeKalb might want to worry more about the water from their bottles than the water from their taps.

Since DeKalb updated its water treatment system in 2000, the levels of harmful chemicals and contaminants have been under federally mandated levels.

“The most controversial issue with our water has been the level of radium,” said Bryan Faivre, assistant public works director. “We used $15 million to build five radium-reducing water treatment plants, pull three high-radium tested wells out of production and make more efficient our water treatment system.”

The Environmental Protection Agency mandates that radium levels cannot be above five picocuries, a measurement of radioactivity, per liter. DeKalb’s water averages between 1.5 and 4.5 pCi/L.

“The danger radium poses is this: When one drinks water with high levels of radium over long periods of time, the radium molecules replace the similar sized calcium molecules in one’s bones,” said Melissa Lenczewski, associate professor of geology. “Radium then emits radioactivity, which causes cancer.”

DeKalb’s water supply contains no other chemicals or contaminants above EPA regulated levels. However, the water in the three new shallow wells that replaced the deep, high-radium wells in 2000 contain high levels of iron.

“Iron isn’t dangerous; some people don’t like how it tastes though,” Faivre said. “So we filter that out too.”

The process water goes through is both state of the art and simple.

Water is pumped from either deep or shallow wells, of which DeKalb has nine.

The raw water from the shallow wells flows to a tank containing sand, which collects the iron particles as they pass.

Half the raw water from the deep wells is combined with a salt solution in a tank that acts as a giant water softener. In the water softener, salt is exchanged for radium in the water in a process called ion exchange. The other half of the water is not treated with salt to make the water less acidic.

“If we treated all our water, it would eat through the pipes as it travels,” Faivre said.

All the water is then combined, and fluoride, chlorine and phosphates are added.

“The water that comes out tastes great,” Faivre said. “But it is in the pipes of homes, dorms or while the water sits in a water fountain that can give our water a bad taste.”

The alternative, bottled water, is also an imperfect choice.

“First, the rigorous testing of U.S. water is not imposed on commercial water bottling companies,” Lenczewski said. “Second, fluoride is not required in bottled water, so those who drink tap water, in which fluoride is required, statistically have fewer cavities.”