A. Premises having an auxiliary water supply;

B. Premises having internal cross-connections that are not correctible, or intricate plumbing arrangements which make it impracticable to ascertain whether or not cross-connections exist;

C. Premises where entry is restricted so that inspections for cross-connection cannot be made with sufficient frequency or at sufficiently short notice to assure that cross-connections do not exist;

D. Premises having a history of cross-connections being established or reestablished;

E. Premises on which any substance is handled under pressure so as to permit entry into the public water system, or where a cross-connection would reasonably be expected to occur. This includes the handling of process waters and cooling waters;

F. Premises with commercial or residential water softener units (backwash);

G. Premises where materials of a toxic or hazardous nature are handled such that if backflow should occur, a serious health hazard may result;

H. The following types of facilities will fall into one of the categories set out in subsections A through G of this section where a backflow-prevention device shall be installed at these facilities as set forth in the California Administrative Code, Title 17, Public Health, unless the director of public works determines that no health hazard exists: