(A) Generally.
(1) Any customer either operating or planning to operate facilities identified by the county as having a potential for backflow into the county’s public water supply system shall install an approved backflow prevention assembly on all such service connections according to the degree of hazard present. The following facilities have been identified by the county as having a potential for backflow and require backflow prevention assemblies as indicated.
(2) These guidelines are supplemental to § 1006(b) of the Rules Governing Public Water Supplies.
(B) Degree of hazard.
(1) Severe. Actual or potential threat of contamination that presents imminent danger to the public health with consequence of serious illness or death.
(2) Moderate. One that presents foreseeable and significant potential for pollution, nuisance, aesthetically objectionable, or other alterations of the drinking water supply.
(C) Backflow prevention assembly requirements.
Degree of Hazard | (RP) Reduced Pressure Zone | (DCVA) Double-Check Valve Assembly | (AG) Air Gap |
Moderate | X | ||
Severe | X | X |
(1) Automotive service station; dealerships:
(a) Moderate hazard: DCVA; or
(b) Severe hazard (e.g., wash pits, hydraulic equipment): RP.
(2) Bakeries: DCVA;
(3) Beauty shops/barber shops:
(a) Moderate hazard (e.g., hair cuts): DCVA; or
(b) Severe hazard (e.g., washing hair, chemical treatment): RP.
(4) Beverage bottling plants or breweries: RP;
(5) Canneries, packing houses, or rendering plants: RP;
(6) Chemical processing plants: RP;
(7) Church baptismal: DCVA;
(8) Commercial car wash facilities: RP;
(9) Commercial establishments using processed water:
(a) Moderate hazard: DCVA; or
(b) Severe hazard: RP.
(10) Commercial greenhouses: RP;
(11) Concrete/asphalt plants: RP;
(12) Dairies or cold storage plants: RP;
(13) Dentist or orthodontist: RP;
(14) Dye works: RP;
(15) Fanning:
(a) Moderate hazard: DCVA; or
(b) Severe hazard (e.g., chemicals, booster pump, direct watering): RP.
(16) Film laboratories or photo processing: RP;
(17) Fire systems:
(a) Moderate hazard: DCVA; or
(b) Severe hazard (e.g., foam, antifreeze, booster pump): RP.
(18) Funeral homes: RP;
(19) Hospital, medical buildings, or medical clinics: RP;
(20) Laboratories: RP;
(21) Laundries:
(a) Moderate hazard: DCVA; or
(b) Severe hazard (e.g., dry cleaners): RP.
(22) Lawn irrigation systems:
(a) Moderate hazard: DCVA; or
(b) Severe hazard (e.g., booster pump, chemical system): RP.
(23) Metal manufacturing, cleaning, processing, or fabricating plants: RP;
(24) Morgues, mortuaries, or autopsy facilities: RP;
(25) Multi-story buildings:
(a) (Three or four stories) moderate hazard: DCVA; or
(b) (Five or more stories) severe hazard: RP.
(26) Nursing and convalescent homes: RP;
(27) Oil and gas production, storage, or transmission properties: RP;
(28) Pest control (exterminating or fumigating): RP;
(29) Power plants: RP;
(30) Restaurants: DCVA;
(31) Restricted, classified, or other closed facilities: RP;
(32) Sand or gravel plants: RP;
(33) Schools:
(a) Moderate hazard: DCVA; or
(b) Severe hazard: RP.
(34) Sewage or storm drain facilities: RP;
(35) Swimming pools: RP;
(36) Veterinary hospitals or clinics: RP;
(37) Wastewater treatment plants: RP;
(38) Water treatment plants: RP; or
(39) Waterfront commercial facilities and industries: RP.
(D) Other types of facilities. Other types of facilities not listed may also be required to install approved backflow prevention assemblies if determined necessary by the county.
(E) Approved backflow prevention assemblies. Approved backflow prevention assemblies shall be installed on the customer’s system at the point of service to any facility that the county identifies as having a potential for backflow. These assemblies must meet the American Society of Sanitary Engineering (ASSE) standard and carry an ASSE seal or is on the University of Southern California approval list or is an assembly approved by the county.
(F) Backflow prevention assembly installation. Backflow prevention must be located in a place where it is readily accessible for regular testing, maintenance, and inspection. By-pass lines parallel to a backflow prevention assembly shall have an approved backflow prevention assembly installed that is equal to that on the main line.
(1) Reduced pressure zone:
(a) Above-ground installation preferred;
(b) Below-ground vault shall have positive drainage with adequate gravity drainage to atmosphere; and
(c) Twelve-inch minimum clearance with manufacturer’s recommendations.
(2) Double-check valve assembly:
(a) Vertical or horizontal installation acceptable; and
(b) Adequate drainage shall be provided if installed below-ground.
(Ord. 95-1, passed 1-9-1995; Ord. passed 1-8-2007)