Fluoridation of Drinking Water

Washington State does not require public water systems to add fluoride to drinking water. The decision to fluoridate drinking water is a local community decision. After a community makes the decision to fluoridate its drinking water, we provide technical assistance to ensure fluoridation treatment is designed, installed, and operated in a manner that meets fluoride safety standards. Washington Administrative Code (WAC) 246-290-460, Fluoridation of drinking water, sets the allowed fluoridation concentration range for water systems that add fluoride to their water for dental health benefits. 

Recent Legislative Changes for Public Water Systems

During this past Legislative Session, House Bill 1251 was passed and signed by Governor Inslee on April 20, 2023. The purpose of this bill is to set notification requirements for public water systems that want to start adding fluoride to their drinking water, or systems that would like to discontinue adding fluoride to their drinking water. Starting July 23, 2023, public water systems considering starting or discontinuing fluoridation of their water on a continuing basis must notify their customers and ODW, at least 90 days prior to a vote or decision on the matter. 

Water systems can notify customers by radio, television, newspaper, regular mail, electronically, or by any combination of methods that most effectively notify customers. If a water system fails to meet the new notification requirements it must continue with its current fluoridation practice until it meets the notification requirements.    

The Board is not currently considering new rulemaking activities relating to fluoridation. However, the Board may decide to consider rulemaking relating to fluoridation in the future.  

Learn more about fluoride in drinking water:

What is fluoride?

Fluoride is a naturally occurring mineral that protects teeth from tooth decay. Almost all water contains some naturally occurring fluoride, but usually not enough to prevent tooth decay. Many communities adjust the amount of fluoride in the water supply to a level known to reduce tooth decay and promote good oral health.

Is my drinking water fluoridated?

At your next dentist appointment, you may be asked, "Is your drinking water fluoridated?" When developing a fluoride treatment plan, your dentist will consider all the ways you might be getting fluoride. This can include the water you drink, food and beverages made with fluoridated water, and fluoridated tooth paste. To protect your teeth from cavities, your dentist will want you to get the "optimum" level of fluoride.

To read more about how fluoride is added to drinking water, and how to know if your water system adds fluoride, see Questions and Answers: Is my drinking water fluoridated? 331-409 (PDF). Your dentist will want to know if fluoride is added.

Map of Systems that Deliver Fluoridated Water

Map of fluoridated systems in WA.

Map of Naturally Occurring Fluoride by County

Map of naturally occuring fluoride in WA water systems.

If you have questions on fluoride in drinking water, contact Andy Schut, Water Quality Assessment Specialist/Lab Liaison, at 360-236-3197.

For general information on the benefits of fluoride, visit our Oral Health page.

For healthcare provider information on fluoride, visit our Fluoride and Fluoridation page.