A CCS shall determine the type of backflow assembly to be installed within the area served by the District. All assemblies shall be installed at the service connection unless it is determined by the CCS to install the assembly at an alternate location. The cross-connection shall be eliminated or at a minimum, a double-check valve assembly for premise isolation shall be required to be installed in each of the following circumstances, but the CCS is in no way limited to the following circumstances:
- The nature and extent of any activity on the premises, the materials used in connection with any activity on the premises, or materials stored on the premises, could contaminate or pollute the potable water supply.
- Premises having any one or more cross-connections or potential cross-connections as that term is defined in the Policy, the District's current SOP Manual, the Washington Administrative Code, and all applicable plumbing codes.
- When a cross-connection survey report form is required by the District to be filled out and the District has not received it.
- Internal cross-connections are present that are not correctable.
- Intricate plumbing arrangements exist or plumbing subject to frequent changes is present that make it impractical to ascertain whether or not cross-connections exist.
- There is a repeated history of cross-connections being established or re-established.
- There is unduly restricted entry so surveys for cross-connections cannot be made with sufficient frequency to assure that cross-connections do not exist.
- Materials, chemicals, or any substance or apparatus are being used so that if backflow occurs contamination would result.
- Installation of an approved backflow prevention assembly is deemed to be necessary in the judgment of the CCS to accomplish the purpose of this Policy.
- In the event an in-premise assembly has not been tested or repaired as required by the WAC 346-290-490, or as amended, this Policy and the District's current SOP Manual.
- If it is determined that additions or rearrangements have been made to the plumbing system without obtaining proper permits as required by the County Code Enforcement Division.
- All high health hazard premises, which are included in but not limited to Table 9 of the WAC section 246-290-490, or as amended, are required to have premises isolation by installing a reduced pressure principle assembly in accordance with this Policy and the District's current SOP Manual.
- When a garden hose attachment is connected to the premises plumbing, including but not limited to fertilizer applicators, pesticide applicators, and radiator flush kits.
- Where reclaimed or reused water systems are installed.
- Premises on which any substance is handled under pressure so as to permit entry into the public water system.