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Chemical reference number (CAS): 7440-23-5

Sodium is a naturally occurring mineral that is essential for life. In the body, sodium controls fluid balance, helps send nerve impulses and affects muscle function. Low levels of sodium is naturally found in foods, lakes and rivers, and groundwater. Sodium is used in certain types of water treatment, for road de-icing, and to make a variety of consumer products.

Most of our exposure to sodium comes from food. In general, packaged, prepared, and restaurant foods contain the most amount of sodium. We can also be exposed to sodium from drinking water. The largest sources of sodium in Wisconsin's drinking water are road salt and water softeners.

There are no state or federal standards for the amount of sodium allowed in drinking water.

The Department of Health Services (DHS) recommends a threshold of 20 milligrams per liter (mg/L) for people that are on a low sodium or “no salt" diet. In these cases, DHS recommends that people use bottled water for drinking. You should talk to your doctor if you are on a low sodium diet and are concerned about your water quality. You can learn about the level of sodium in your drinking water by contacting your water utility or testing your private well.

The United States Environmental Protection Agency (EPA) has more information about this health threshold for people on low sodium diets.

Everyone's Reaction is Different

A person's reaction to chemicals depends on several things, including individual health, heredity, previous exposure to chemicals, including medicines, and personal habits, such as smoking or drinking. It’s also important to consider the length of exposure to the chemical, the amount of chemical exposure, and whether the chemical was inhaled, touched, or eaten.


High levels of sodium in drinking water do not pose a health threat to most people.

However, for people with pre-existing heart conditions, too much sodium can increase the risk for negative health effects.

The American Heart Organization has more information on how sodium can affect our health.

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Last revised April 22, 2021