Depending on where you live in Colorado, your drinking water could be contaminated with radiation.

Target 13 Investigates reviewed 21,027 water tests from across the state, and found radiation that can cause cancer is widespread in the groundwater.

More than 50 drinking water suppliers have had so much radiation in their water they violated the government contaminant levels at least once over the past 10 years.

One of the hot zones is east of Pueblo -- the lower Arkansas Valley. Some of the larger towns, like La Junta, Lamar and Rocky Ford have been able to lower their radiation below the legal standard, but are still above the safe health standard of 0.

In your drinking water the Environment Protection Agency allows a Maximum Contaminant Level (MCL) of 5 Picocuries per liter (pCi/L) for radium. 15 pCi/L for Gross Alpha, and 30 Microgram per liter (ug/l).

Bottom line, that's how many radionuclides, that emit radiation, the government allows in your tap water. You should know the EPA's Maximum Contaminant Level Goal (MCLG) is zero for those contaminants, because radionuclides are not considered safe when they get inside your body.

The EPA website states the MCL is set "using the best available treatment technology and taking cost into consideration."

"We know these things can cause cancer when in contact with human cells," explained Dr. John Spear, a professor at the Colorado School of Mines who's studied radionuclides for 20 years.

He said the EPA's MCL is a legal enforceable limit and it does lower the cancer risk for most people, but no scientist will say the water you're drinking is safe if it tests above zero.

Target 13: What would happen if they're drinking water that's in violation (of EPA's MCL)?

Dr. Spear: If they're drinking water that's in violation they're going to have much higher chance.

Target 13: "If they're drinking water at a 1?

Dr. Spear: If they're drinking water that's at a 1 they're going to have a chance, if they're drinking water way above the standard they're going to have a better chance.

Target 13: Of getting cancer.

Dr. Spear: Of getting cancer.

Even the EPA states in the December 2000 Federal Register when it set the radionuclides final rules, "a single alpha passing through a cell is sufficient to induce a mutational event."

The town of Swink, east of Pueblo, is in violation of the EPA's MCL. The town sends out public notices when water tests show they're in violation, which happens roughly once a year. The last notice sent was on page 3 of the town newsletter.

We talked many people in Swink who clearly did not understand that their drinking water violates the EPA's contaminant level for radionuclides.

One person said, "they (town leaders) told us it's got lead, but I never heard anything about what you just said."

Target 13: "About radioactivity?"

Swink resident: "Yeah, I never heard of that."

Most we talked to know there's something in the waterm but not much else about it.

Target 13: "Do you understand exactly what the radioactive material is, or if there is any?"

Resident: "Uh. That I don't know."

One woman told us, "I'm sure a lot of people drink it because we've been told it's acceptable."