An Associated Press investigation discovered prescription drugs in the water supply of 41 million Americans. The drugs were detected in 24 metropolitan areas including Detroit and Louisville.

While the amounts are very small, scientists worry about the long-term consequences to human health.

Officials say people in our area should not be concerned.

The St. Joseph River is an example of what's called surface water. This is the type of water used in those places where the prescription drugs were detected. But that's not the type of water we use here.

"In St. Joe County, in Elkhart County, northwestern Indiana, we're extremely lucky to have this,” said Dave Tungate of South Bend Water Works.

Unlike many other places around the country, the water we use comes from an aquifer system, or the ground.

"I'm having a harder time grasping how the pharmaceuticals could ever get 100-150 foot deep in a groundwater supply like South Bend has,” said Gary Gilot of South Bend Public Works.

Not only is the water hundreds of feet underground, it's also protected by a layer of clay called an aquitard.

"So our water should be inherently more protected than surface water supplies,” Tungate explained.

The cities with traces of prescription drugs use surface water supplies -- like lakes and rivers, and officials say they tend to be more prone to contaminants.

"It’s vulnerable to storm water runoff,” Gilot said. “It's vulnerable to water foul, various other animals, vulnerable to combined sewer overflows."

The Environmental Protection Agency regulates drinking water standards through the Safe Water Drinking Act. This includes testing for hundreds of chemicals, but it doesn't include prescription drugs.

And officials in South Bend say since it's very unlikely they'd be found in the water here, they don't test for them.

"The safety and the purity of our drinking water is of utmost concern to us all the time,” Tungate said. “But we have no reason to believe that there is a problem with our water."

The AP also surveyed 52 smaller water communities, including Michigan City, to find out if they tested for prescription drugs. Only one city in Kansas said they did.