Fluoridation of drinking water.
(1) Purveyors shall obtain written department approval of fluoridation treatment facilities before placing them in service and shall notify the department before discontinuing fluoridation.
(2) Where fluoridation is practiced, the optimal fluoride concentration is 0.7 mg/L.
(3) To ensure concentrations remain as close as possible to the optimal fluoride concentration throughout the entire distribution system and fluoridation facilities and monitoring equipment are operating properly, purveyors shall take the following actions:
(i) Each business day, collect routine monitoring samples downstream from each fluoride injection point at the first sample tap where adequate mixing has occurred.
(ii) Analyze samples in accordance with procedures identified in the 22nd edition of Standard Methods for the Examination of Water and Wastewater, January 2012, or other department-approved procedures.
(iii) Once per month, collect a split sample at the same location routine monitoring samples are collected and process as follows:
(A) Analyze half the sample and record the results on the chain of custody document; and
(B) Submit the other half of the sample for analysis to a drinking water certified laboratory with the chain of custody document.
(i) Record routine analysis results on a monthly report form provided by the department.
(ii) If more than one routine monitoring sample is collected on any given day, average sample results and record the average.
(iii) Submit monthly monitoring reports to the department within the first ten days of the month following the month in which the samples were collected.
(4) If any sample or measurement in subsection (3) of this section is found to be out of operating tolerance or off measure, the purveyor shall take appropriate action to meet the requirements of this section.
(a) Operating tolerance means within the range of 0.5 to 0.9 mg/L.
(b) Off measure means the drinking water certified laboratory result differs by more than 0.2 mg/L from the purveyor's analytical result.
(5) The department may require the purveyor to increase the frequency, or change the location of sampling prescribed in subsection (3) of this section to ensure adequacy and consistency of fluoridation.
[Statutory Authority: RCW 43.20.050
. WSR 16-09-008, § 246-290-460, filed 4/8/16, effective 5/9/16. Statutory Authority: RCW 43.02.050
[43.20.050]. WSR 99-07-021, § 246-290-460, filed 3/9/99, effective 4/9/99. Statutory Authority: RCW 43.20.050
. WSR 91-02-051 (Order 124B), recodified as § 246-290-460, filed 12/27/90, effective 1/31/91. Statutory Authority: RCW 34.04.045
. WSR 88-05-057 (Order 307), § 248-54-235, filed 2/17/88. Statutory Authority: RCW 43.20.050
. WSR 83-19-002 (Order 266), § 248-54-235, filed 9/8/83.]