A. Backflow prevention devices shall be installed at the ties on the premises or the materials used in connection with service connection or within any premises where, in the judgment of the purveyor, the nature and extent of the activities, or the materials 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 the time the backflow prevention devices shall be installed under circumstances, including, but not limited to, the following:
1. Premises having auxiliary water supply.
2. Premises having internal cross connections that are not correctable, or intricate plumbing arrangements which make it impractical 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:
a. Chemical plants using a water process.
b. Food or beverage processing plants.
c. Hospitals, mortuaries, clinics.
d. Laboratories.
e. Metal plating industries.
f. Petroleum processing or storage plants.
g. Radioactive material processing plants or nuclear reactors.
h. Sewage treatment plants.
8. Other premises, as specified by the supervisor, 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 of a reduced pressure principle backflow prevention device shall be installed where the public water supply may be contaminated with sewage, industrial waste of toxic nature, or other contaminant which could 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, pressure vacuum breaker assembly, atmospheric vacuum breaker, 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 purveyor. 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 purveyor or the supervisor.
E. Any protective device required by this chapter shall be a model approved by the supervisor.
There shall be no connection between the distribution system and any pipes, pumps, hydrants, water loading stations or tanks whereby unsafe water or other contaminating materials may be discharged or drawn into a public water system. The water purveyor is responsible through its cross connection control program to take reasonable and prudent measures to protect the water system against contamination and pollution from cross connections through premises isolation or containment, internal or in plan isolation, fixture protection, or some combination of premises isolation, internal isolation and fixture protection.
1. Testable Assemblies: All double check valve backflow prevention assemblies, reduced pressure principle backflow prevention assemblies, spill resistant vacuum breakers, and pressure vacuum breakers used must pass a performance test conducted by the University Of Southern California Foundation For Cross Connection Control And Hydraulic Research. In addition, all double check valve backflow prevention assemblies and reduced pressure principle backflow prevention assemblies used shall meet American Water Works Association (AWWA) standards C-510 or C-511, incorporated by reference into these rules at subsection 002.01, or an equivalent standard approved by the department.
2. Atmospheric Vacuum Breakers: All atmospheric vacuum breakers used shall be marked approved either by the International Association Of Plumbing And Mechanical Officials (IAPMO) or by the American Society Of Sanitation Engineers (ASSE).
3. Resilient Seated Shutoff Valves: Resilient seated shutoff valves shall be used when double check valve backflow prevention assemblies, reduced pressure principle backflow prevention assemblies and pressure vacuum breakers are installed.
4. Expense: 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 at least annually, but 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, overhauled or replaced at the customer's expense. Inspections, tests, repairs and records thereof shall be accomplished by a tester licensed by the Idaho bureau of occupational licenses.
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. Refer to the uniform plumbing code for approved devices in regards to underground sprinkling devices.
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 terminating water service to the premises, or, in the alternative, the installation of an air gap separation at the customer's expense. (1984 Code § 7-3C-4)