The secretary may revoke or suspend a certificate: (1) Found to have been obtained by fraud or deceit; (2) for fraud, deceit, or gross negligence involving the operation or maintenance of a public water system; (3) for fraud, deceit, or gross negligence in inspecting, testing, maintenance, or repair of backflow assemblies, devices, or air gaps intended to protect a public water system from contamination; or (4) for an intentional violation of the requirements of this chapter or any lawful rules, order, or regulation of the department. No person whose certificate is revoked under this section shall be eligible to apply for a certificate until the completion of the revocation period.