WSSC Water is temporarily reducing the level of fluoride added to the drinking water of its nearly 2 million customers in Montgomery and Prince George’s counties in Maryland.

The utility said in a news release the reduction is due to “nationwide supply challenges linked in part to the ongoing conflict in the Middle East.”

Starting Wednesday afternoon, fluoride levels will go down from approximately .7 milligrams per liter to .4 milligrams per liter.

According to WSSC Water, one major supplier of hydrofluorosilicic acid, the compound used to fluoridate water, is based in Israel and has experienced “significant operational impacts” in recent months.

Fluoride is not mandated by federal or state regulations, but is recommended by the Centers for Disease Control and Prevention and the World Health Organization to help strengthen teeth and prevent cavities, WSSC Water said.

“This is a temporary adjustment driven solely by supply availability,” WSSC Water’s Director of Production Ben Thompson said in a news release. “We remain committed to maintaining safe, high-quality drinking water and will restore optimal fluoride levels as soon as supply conditions stabilize.”

The utility encouraged customers to talk to their dentist or health care provider about alternative sources of fluoride while the reduction is in effect.

WSSC Water did not say when normal fluoride levels would be restored.