(1) For a system providing a limited alternative to filtration, the purveyor using a surface water or GWI source shall meet the source quality and site-specific conditions under this section.

(2) Source water turbidity requirements.

(a) The purveyor shall ensure that the turbidity level in representative source water samples taken before primary disinfection does not exceed 5.0 NTU.

(b) A system with more than two turbidity events in the twelve previous calendar months the water was served to the public or more than five turbidity events in the one hundred twenty previous calendar months the water was served to the public shall expand the scope of its next annual comprehensive report required under WAC 246-290-696(6) to include:

(i) A description of the events;

(ii) A summary of previous turbidity events;

(iii) A proposed plan of corrective action; and

(iv) A schedule for implementing the action plan.

(3) Site-specific requirements.

(a) Level of inactivation.

(i) The purveyor shall ensure that the removal and/or inactivation levels required under WAC 246-290-630(11) are met in at least eleven of the twelve previous calendar months that the system served water to the public.

(ii) A system failing to meet the inactivation requirements in (a)(i) of this subsection in two or more months of the previous twelve calendar months the system served water to the public shall expand the scope of its annual comprehensive report required under WAC 246-290-696(6) to include:

(A) A description of the failure(s);

(B) A summary of previous inactivation failures;

(C) A proposed plan of corrective action; and

(D) A schedule for implementing the action plan.

(b) Watershed control.

(i) The watershed must not be allowed to be inhabited, except for those designated individuals and for those periods of time each year that would be directly associated with the protection of the watershed.

(ii) The purveyor shall develop and implement a department-approved watershed control program.

(iii) The purveyor shall monitor, limit, and control all facilities and activities in the watershed affecting source quality to preclude degradation of the physical, chemical, microbiological (including viral and Cryptosporidium oocysts contamination), and radiological quality of the source. The purveyor shall demonstrate, through ownership and/or written agreements acceptable to the department, control of all human activities that may adversely impact source quality.

(iv) At a minimum, the purveyor's watershed control program shall:

(A) Characterize the watershed hydrology and land ownership;

(B) Identify watershed characteristics and activities that may adversely affect source water quality; and

(C) Monitor the occurrence of activities that may adversely affect source water quality.

(v) If the department determines significant changes have occurred in the watershed, the purveyor shall submit, within ninety days of notification, an updated watershed control program to the department for review and approval.

(vi) The purveyor may be required to conduct additional monitoring to demonstrate the adequacy of the watershed control program.

(vii) A purveyor shall be considered out of compliance when failing to:

(A) Have a department-approved watershed control program;

(B) Implement the watershed control program to the satisfaction of the department;

(C) Conduct additional monitoring as directed by the department; or

(D) Prevent the human inhabitation of the watershed, except during the periods of time when conducting watershed protection activities as provided in (b)(i) of this subsection.

(c) On-site inspections.

(i) The purveyor shall submit to on-site inspections by the department to assess watershed control and disinfection treatment.

(ii) The purveyor shall submit to annual inspections by the department unless more frequent inspections are deemed necessary to protect the health of consumers served by the system.

(iii) The purveyor with unsatisfactory on-site inspection results shall take action as directed by the department in accordance with a department-established schedule.

(d) Waterborne disease outbreak.

(i) The system shall not be identified by the department as the cause of a waterborne disease outbreak attributable to a failure in treatment of the surface or GWI source.

(ii) A system identified by the department as the cause of a waterborne disease in (d)(i) of this subsection shall expand the scope of its annual comprehensive report required under WAC 246-290-696(6) to include:

(A) A description of the outbreak;

(B) A summary of previous waterborne disease outbreaks attributed to the system;

(C) A proposed plan of corrective action; and

(D) A schedule for implementing the action plan.