(A) Backflow prevention devices shall be installed at the service connection or within any premises where, in the judgment of the city, the nature and extent of activities, or the material stored on the premises, would present an immediate and dangerous hazard to health and/or be deleterious to the quality of the water should a cross connection occur; even though such cross connection does not exist at present, the backflow prevention devices shall be installed under circumstances including, but not limited to, the following:
1. Premises having an auxiliary water supply, unless the quality of the auxiliary supply is in compliance with the Idaho drinking water regulations and is acceptable to the city.
2. Premises having internal cross connections that are not correctable, or intricate plumbing arrangements which make it impracticable to ascertain whether or not cross connections exist.
3. Premises where entry is restricted so that inspections for cross connections cannot be made with sufficient frequency or at sufficiently short notice to assure that cross connections do not exist.
4. Premises having a repeated history of cross connections being established or reestablished.
5. Premises on which any substance is handled under pressure so as to permit entry into the public water supply, or where a cross connection could reasonably be expected to occur. This shall include the handling of process waters and cooling waters.
6. Premises where materials of a toxic or hazardous nature are handled in such a way that if back siphonage should occur, a serious health hazard might result.
7. The following types of facilities will fall into one of the above categories where a backflow prevention device is required to protect the public water supply. A backflow prevention device shall be installed at these facilities unless the city determines that no hazard exists:
(a) Sewage treatment plants.
(b) Chemical or other industrial plants.
(c) Agricultural chemical storage, formulation and distribution facilities.
(d) Petroleum storage facilities.
(e) Underground sprinkling devices or systems.
8. Other premises, as specified by the city, where backflow prevention devices are required to protect the public water supply.
(B) The type of protective device required shall depend on the degree of hazard which exists:
1. An air gap separation or a reduced pressure principle backflow prevention device shall be installed where the public water supply may be contaminated with sewage, industrial waste of a toxic nature or other contaminant which would cause a health or system hazard.
2. In the case of a substance which may be objectionable but not hazardous to health, a double check valve assembly, air gap separation or a reduced pressure principle backflow prevention device shall be installed.
(C) Backflow prevention devices required by this chapter shall be installed at the meter, at the property line of the premises when meters are not used, or at a location designated by the city. The device shall be located so as to be readily accessible for maintenance and testing, and furthermore, where no part of the device will be submerged.
(D) Backflow prevention devices required by this chapter shall be installed under the supervision of, and with the approval of, the supervisor.
(E) Any protective device required by this chapter shall be a model approved by the city. A double check valve assembly or a reduced pressure principle backflow prevention device will be approved if it has successfully passed performance tests of the University of Southern California Engineering Center or other testing laboratories satisfactory to the engineer. These devices shall be furnished and installed by and at the expense of the customer.
(F) Backflow prevention devices installed pursuant to this chapter, except atmospheric vacuum breakers, shall be inspected and tested annually, or more often if necessary. Inspections, tests and maintenance shall be at the customer's expense. Whenever the devices are found to be defective, they shall be repaired or replaced at the customer's expense. Inspections, tests, repairs and records thereof shall be accomplished under the city's supervision by certified testers.
(G) No underground sprinkling device will be installed without adequate backflow prevention devices at the point from which the water for irrigation is taken from the public water supply.
(H) Failure of the customer to cooperate in the installation, maintenance, testing or inspection of backflow prevention devices required by this chapter shall be grounds for the termination of water service to the premises, or, in the alternative, the installation of an air gap separation at the customer's expense. (Ord. 266, 4-13-1981)