Radium in Community Water Systems

For Minnesota's Community Water Systems:

Radium occurs naturally in the environment.

Radium occurs naturally in our environment. It is a natural component of underground rock and soil, and it can work its way into ground water. Long-term exposure to radium in drinking water may result in an increased risk of cancer. Studies of radium in groundwater across many parts of North America indicate that some areas in Minnesota are within zones where radium is present at higher levels.

By law, all community water systems must be monitored for radioactivity. Systems are on different monitoring frequencies based on historical results. Depending on historical results systems may monitor quarterly, annually, triennially, once every 6 years or every 9 years. Radium and other levels of radioactivity in water are measured in picocuries per liter (pCi/L) of water. The MCL for radium is 5 picocuries per liter (pCi/L). If a system's radium levels are above the federal maximum contaminant level (MCL), MDH will help the system reduce radium.


Mean radium levels in Minnesota Community Water Systems

Percent of tested systems, by mean radium concentration
The federal Maximum Contaminant Level (MCL) for radium is 5 picocuries per liter (pCi/L).
The federal Maximum Contaminant Level (MCL) for radium is 5 picocuries per liter (pCi/L).

Maximum radium levels of Minnesota Community Water Systems

Percent of tested systems, by maximum radium concentration
The federal Maximum Contaminant Level (MCL) for radium is 5 picocuries per liter (pCi/L).
The federal Maximum Contaminant Level (MCL) for radium is 5 picocuries per liter (pCi/L).

Most drink water with radium below the MCL

Population Served

People served, by mean radium annual concentration of their Community Water Systems, 2015
Radium level Number of Systems Population Served Percent
0-3 848 3,590,574 90.1%
3-5 73 561,025 7.8%
5-10 20 139,294 2.1%
10+ 0 0 0.0%

What can be done about radium in drinking water?

Sometimes a system can find a new water source. It may also blend water from more than one source to the point that the blended water does not have unacceptable levels of radium. Another option is to install a treatment process to reduce the radium levels. Treatment options include cation exchange (which is similar to home water softening), reverse-osmosis, lime softening, and electrodialysis. In addition, studies have shown that filtering the water through greensand or anthracite may be effective. A water system will consider many factors, including cost, in deciding on an option.

Related resources:

Radium in Drinking water

Radionuclides Rule: EPA Drinking Water requirements for states and public water systems