A. An approved backflow prevention method shall be utilized or installed at every service connection to a customer's water supply system when the Department determines, according to the criteria included herein, that the potable water supplied by the public potable water system may be subject to contamination, pollution, or other deterioration in sanitary quality by conditions within the customer's water system.
B. Backflow preventive devices approved by the Director shall be installed and maintained by and at the expense of the water user.
C. The backflow method to be utilized or installed shall be determined by the Director, according to the criteria included herein. The method required by the Director shall be sufficient to protect against the potential degree of hazard, as determined by the Director, to the public potable water supply from the customer's water system.
D. The degree of hazard potential to the public potable water supply and system from a customer's water supply system shall be determined using the following hazard factors:
1. Health. Any condition, device, or practice which, in the judgment of the Department, may create a danger to the health and well-being of the potable water customers.
2. Plumbing. A plumbing type cross-connection that is not properly protected by an approved backflow prevention method.
3. Pollution. An actual or potential threat to the physical facilities of the public potable water supply system or to the public potable water supply which, although not dangerous to health, would constitute a nuisance or be aesthetically objectionable, or could cause damage to the system or its appurtenances.
4. System. An actual or potential threat which may cause severe damage to the physical facilities or the public potable water supply system or which may have a protracted effect on the quality of the potable water in the system.
E. A backflow prevention method shall be an assembly or other means designed to prevent backflow. The following are the recognized backflow prevention methods which the Department may require:
1. Air gap. The unobstructed vertical distance through the free atmosphere between the lowest opening from any pipe or faucet supplying water to a tank, plumbing fixture or other device and the flood level rim of the vessel. An approved air gap shall be at least double the diameter of the supply pipe, measured vertically, above the overflow rim of the vessel; and in no case less than 1 inch (most restrictive);
2. Reduced pressure principle assembly. An assembly of 2 independently acting approved check valves together with a hydraulically operating, mechanically independent differential pressure relief valve located between the check valves and at the same time below the first check valve. The unit shall include properly located resilient seated test cocks and resilient seated shut off valves at each end of the assembly (RPA);
3. Double check valve assembly. An assembly of 2 independently operating approved check valves with properly located resilient seated test cocks and resilient seated shut off valves at each end of the assembly (DCVA);
4. Pressure vacuum breaker assembly. An assembly containing an independently operating loaded check valve and an independently operating loaded air inlet valve located on the discharge side of the check valve. Must be equipped with properly located resilient seated test cocks and resilient seated shut off valves at each end of the assembly (PVB) (least restrictive); or
5. A backflow prevention method may be approved by the Department if it has received the approval of the Foundation for Cross Connection Control and Hydraulic Research of the University of Southern California (FCCCHR-USC) and manufactured according to the standards established by the American Water Works Association (AWWA).
F. The Department shall maintain a list of approved backflow prevention assemblies, by type and manufacturer. The list shall be furnished to any customer required to install a backflow prevention assembly.
G. Backflow prevention methods requirements.
1. When any of the following activities are conducted on premises served by the public potable water system, a potential hazard to the public potable water supply shall be presumed and a backflow prevention method of the type specified for that activity herein, must be utilized or installed at the service connection for that premise.
a. Cooling tower, boiler, condenser, chiller, and other cooling systems utilizing potable water: RPA.
b. Tank, vessel, receptacle, and all other water connections including mobile units without approved air gap (except emergency vehicles and private swimming pools): RPA.
c. Ice maker (other than a residential service): RPA.
d. Water cooled equipment, boosters, pumps, or autoclaves: RPA.
e. Water treatment facilities and all water processing equipment (other than residential water softeners): RPA.
f. Bottle washer, bedpan washer, garbage can washer: RPA.
g. Pesticide, herbicide, fertilizer, and chemical applicators (other than typical in-home use): RPA.
h. Aspirator: RPA.
i. Commercial dishwashers, food processing and/or preparation equipment, carbonation equipment or other food processes utilizing potable water: RPA.
j. Decorative fountain, baptismal, or any location water is exposed to atmosphere: RPA.
k. X-ray equipment, plating equipment, or any other photographic processing equipment utilizing potable water: RPA.
l. Auxiliary-water supply and/or connections to unapproved water supply systems: RPA.
m. Reclaimed water customers: RPA.
n. Recreation vehicle dump stations (sewer) or any other location where potable water may be exposed to bacteria, virus or gas: RPA.
o. Any premises on which chemicals, oil, solvents, pesticides, disinfectants, cleaning agents, acids, or other pollutant and/or contaminants are handled in a manner by which they come in direct contact with potable water, or there is evidence of the potential to contact potable water: RPA.
p. Materials and piping systems unapproved by the Uniform Plumbing Code (UPC) or Environmental Protection Agency (EPA) for potable water usage: Contaminant: RPA, Pollutant: DCVA.
q. Separately metered irrigation systems and construction water services: RPA.
r. Any premises where a cross-connection is maintained or where internal backflow protection is required pursuant to the Uniform Plumbing Code: RPA.
s. Multi-metered properties with more than 1 meter connected to another or any building 3 stories or greater than 34 feet in height from service level: DCVA.
t. Fire systems - American Water Works Association (AWWA) classes 3, 4, 5, and 6: RPA or RPA with Detector.
u. Fire systems which require backflow prevention and where backflow protection is required on the industrial/domestic service connection that is located on same premises, both service connections will have adequate backflow protection for the highest degree of hazard affecting either system: RPA.
v. Other conditions that the Director has determined may pose a potential hazard to the potable water system.
2. When 2 or more of the activities listed above are conducted on the same premises and served by the same service connection or multiple service connections, the most restrictive backflow prevention method required for any of the activities conducted on the premises shall be required to be utilized or installed at each service connection. The order of most restrictive to least restrictive backflow methods shall be as follow:
a. Air gap (most restrictive);
b. Reduced pressure principle assembly (RPA);
c. Double check valve assembly (DCVA); and
d. Pressure vacuum breaker assembly (PVB) (least restrictive).
(Ord. 24-1330, § 1, passed 4-23-2024)