Radioactivity & Water

There’s been a lot of talk recently about radioactivity in water due to nearby power plants and, in particular, coal ash. The question we want to discuss today:

Does the community need to worry about radioactivity in Charlotte Water’s drinking water?

The answer is no. Charlotte Water routinely monitors for radioactive materials and the test results do not detect any radioactive materials above testing detection limits or public health goals set forth by the EPA. 

Sources of Radioactivity

Radioactivity can be naturally occurring from rocks or minerals, or artificial. Recent articles in the news are citing radioactivity found in coal ash monitoring wells adjacent to coal powered power plants. According to a fact sheet written by the US Geological Society (USGS), “Some trace elements in coal are naturally radioactive. These radioactive elements include uranium (U), thorium (Th), and their numerous decay products, including radium (Ra) and radon (Rn). The vast majority of coal and the majority of fly ash are not significantly enriched in radioactive elements, or in associated radioactivity, compared to common soils or rocks.” It is possible that groundwater or surface water can become contaminated with radioactive elements from coal ash. However, the USGS study also stated “Limited measurements of dissolved uranium and radium in water leachates of fly ash and in natural water from some ash disposal sites indicate that dissolved concentrations of these radioactive elements are below levels of human health concern.”

Charlotte Water Monitoring

Even though dissolved concentrations of these radioactive elements in coal ash are very low, Charlotte Water monitors for signs of any kind of contaminants in our raw water sources (Lake Norman and Mountain Island Lake), throughout the treatment process, and in the finished drinking water. Charlotte Water monitors for dozens of contaminants including indicators of radioactivity such as alpha and beta particles. All drinking water quality monitoring data can be found on the Charlotte Water website. More than 220,000 laboratory tests are run every year to continuously ensure our community’s drinking water is safe for our community.

Charlotte Water tests the treated drinking water for Radium 226 and Radium 228 annually. The EPA requires utilities to test for these radioactive materials every 9 years. The last test was performed in July 2017 and Charlotte Water will test again in April 2018.

Drinking Water Treatment


Charlotte Water uses a multi-stage treatment process at all three drinking water treatment plants. We can remove physical contaminants as well as dissolved contaminants.

In Summary

  1. Coal ash contains extremely low levels of radioactive materials.
  2. According to public reports, power plant monitoring indicates radioactive materials have only been observed in groundwater monitoring wells adjacent to the coal ash basins.
  3. Lake monitoring and drinking water monitoring results do not detect any radioactive materials above detection limits or public health goals set forth by the EPA.
  4. Charlotte Water treatment plants can remove particulate and dissolved contaminants.
  5. More than 220,000 monitoring tests are conducted each year to ensure our community continuously receives safe, clean drinking water.