(1) A purveyor of a Group B system shall notify the department, health officer, and all system consumers in writing within twenty-four hours when the purveyor:

(a) Obtains a water quality sample analysis from a certified lab indicating the presence of E. coli;

(b) Obtains a water quality sample analysis from a certified lab indicating the presence of nitrate at a concentration at or above 10.0 mg/L; or

(c) Is aware of circumstances that pose a threat of acute contamination, such as a flood event.

(2) A purveyor of a Group B system required to monitor water quality under WAC 246-291-300 that is not required to notify consumers within twenty-four hours under subsection (1) of this section shall notify the department, health officer, and all system consumers, in writing, within thirty days of receiving the results from a certified lab if directed by the department or health officer.

(3) If a Group B system constructed prior to January 1, 2014, has an arsenic concentration exceeding 0.010 mg/L, the purveyor shall notify consumers in writing:

(a) By March 31, 2014, if the sample analysis result from a certified lab was obtained prior to January 1, 2014;

(b) Within thirty days of receiving a sample analysis result from a certified lab; or

(c) Within thirty days of adding a new service connection under WAC 246-291-280(3).

(4) The public notification must include the following information:

(a) A description of contamination and any known problem(s);

(b) What the purveyor is doing to resolve the problem(s);

(c) Where to get information about potential health effects;

(d) What the consumers should do to protect their health, including the use of another source of water;

(e) When the purveyor expects the problem(s) to be resolved; and

(f) Group B system contact information, including address, phone number, and if available, an email address.