Haw. Rev. Stat. § 340E-6: Notification of users and department.

(a) Whenever a public water system:

(1) Fails to comply with an applicable maximum contaminant level, treatment technique, or testing procedure requirement of a state primary drinking water regulation;

(2) Fails to perform monitoring required by regulations adopted by the director;

(3) Is subject to a variance granted for an inability to meet a maximum contaminant level requirement;

(4) Is subject to an exemption; or

(5) Fails to comply with the requirements of any schedule prescribed by such a variance or exemption;

the public water system shall promptly notify the department, and in the case of a violation under [paragraph (1)], the local communications media, of the conditions and the extent to which they may impose adverse effects on public health and the corrective action being taken when appropriate.

(b) Notice of any violation determined by the director as posing a serious adverse health effect as a result of short term exposure shall be given as soon as practicable, but not later than twenty-four hours after the violation.

(c) The director shall prescribe by rules the form, content, and manner for giving notice. The rules may contain such additional public notification requirements as the director determines are necessary to best effectuate the purpose of this chapter, including consumer confidence reports, and may also contain alternative notice requirements as allowed by the Federal Act.