Is mouthwash less effective if you rinse your mouth out with water afterwards?

Yes, rinsing your mouth out with water immediately after using mouthwash can reduce its effectiveness. Mouthwash is designed to stay in contact with your teeth and gums for a period of time to allow the active ingredients to work their anti-bacterial and plaque-fighting magic. Rinsing with water shortly after using mouthwash can dilute or wash away the active ingredients, reducing their effectiveness against oral bacteria. To get the full benefits of mouthwash, avoid rinsing your mouth out with water for at least 30 minutes after use.