(1) If the quarterly analysis of a water sample from a public water system by a certified laboratory confirms that the level of fluoride in the sample exceeds one and one-half milligrams per liter (1.5 mg/L), the public water system from which the sample was taken must: Obtain laboratory analysis of water samples monthly for fluoride levels; and
(2) Notify all of its customers that a water sample tested exceeded one and one-half milligrams per liter (1.5 mg/L) of fluoride in a manner established by the department.
(3) Once the monthly analysis of water samples for fluoride conducted pursuant to subdivision (a)(1) confirms that the fluoride level in samples is less than one and one-half milligrams per liter (1.5 mg/L) for three (3) consecutive months, the public water system may resume quarterly laboratory analysis for fluoride.