(1) The purveyor shall notify the department, as soon as possible, but no later than twenty-four hours after the purveyor learns of the following events:

(a) A waterborne disease outbreak potentially attributable to the water system occurs;

(b) The turbidity of the combined filter effluent exceeds 5.0 NTU at any time for any system using slow sand, diatomaceous earth, or for any system serving less than ten thousand people and using conventional, direct, or in-line filtration;

(c) The turbidity of the combined filter effluent:

(i) Exceeds 1.0 NTU at any time for a system serving at least ten thousand people and using conventional, direct, or in-line filtration;

(ii) Beginning January 14, 2005, the turbidity of the combined filter effluent exceeds 1.0 NTU at any time for a system serving less than ten thousand people using conventional, direct, or in-line filtration;

(d) The turbidity of the combined filter effluent exceeds the maximum specified level for an alternative filtration technology approved by the department;

(e) The residual disinfection concentration falls below 0.2 mg/L at the entry point to the distribution system. The purveyor shall also report whether the residual was restored to 0.2 mg/L or more within four hours; or

(f) An event occurs that may affect the ability of the water treatment facility to produce drinking water that complies with this chapter including, but not limited to:

(i) Spills of hazardous materials in the watershed; and

(ii) Treatment process failures.

(2) The purveyor shall report results of monitoring conducted in accordance with WAC 246-290-664 to the department. Monthly report forms shall be submitted within ten days after the end of each month the system served water to the public.

(3) The purveyor shall report, at a minimum, all the information requested by the department using a department-approved form or format including:

(a) Water treatment facility operations information;

(b) Turbidity monitoring results, including:

(i) Source monitoring, if required under WAC 246-290-664(2);

(ii) Combined filter effluent. Continuous measurements shall be reported at equal intervals, at least every four hours, in accordance with a department-approved schedule;

(iii) Individual filter turbidity monitoring results. Systems serving at least ten thousand people and using conventional, direct, or in-line filtration shall report and take follow-up action as prescribed in 40 C.F.R. 141.175(b). Beginning January 14, 2005, systems serving less than ten thousand people shall report and take follow-up action as prescribed by 40 C.F.R. 141.563 and 141.570. Required follow-up action may include development of a filter profile, a filter self-assessment, as described in 40 C.F.R. 141.175 (b)(3) and 141.563(b), or the completion of a comprehensive performance evaluation (CPE).

(c) Disinfection monitoring information including:

(i) Level of inactivation achieved;

(ii) Residual disinfectant concentrations entering the distribution system; and

(iii) Residual disinfectant concentrations within the distribution system.

(d) Total level of removal and inactivation; and

(e) A summary of water quality complaints received from consumers served by the water system.

(4) A person certified under chapter 246-292 WAC shall complete and sign the monthly report forms required in this section.