Generating hydrogen peroxide in situ in a water environment to mitigate biofouling of a water sensor. A hydrogen peroxide generator submerged in the water environment generates hydrogen peroxide to remove/mitigate biofouling of the water sensor. The water sensor may be an electrochemical sensor and the hydrogen peroxide generator may be an electrochemical system that is integrated with the sensor. The water sensor may be able to operate without interference from the generated hydrogen peroxide.