A. 
Unprotected cross-connections with the public water supply are prohibited.
B. 
Whenever backflow protection has been found necessary, the city will require the water user to install an approved back-flow prevention device by and at his/her expense for continued services or before a new service will be granted.
C. 
Wherever backflow protection has been found necessary on a water supply line entering a water user’s premises, then any and all water supply lines from the city’s mains entering such premises, buildings or structures shall be protected by an approved backflow prevention device. The type of device to be installed will be in accordance with the requirements of this chapter.
(Ord. 88-01 § 3(A), 1988)
A. 
Each service connection from the city water system for supplying water to premises having an auxiliary water supply shall be protected against backflow of water from the premises into the public water system unless the auxiliary water supply is accepted as an additional source by the city, and is approved by the public health agency having jurisdiction.
B. 
Each service connection from the city water system for supplying water to any premises on which any substance is handled in such fashion as may allow its entry into the water system shall be protected against backflow of the water from the premises into the public system. This shall include the handling of process waters and waters originating from the city water system which have been subjected to deterioration in sanitary quality.
C. 
Backflow prevention devices shall be installed on the service connection to any premises having (1) internal cross-connections that cannot be permanently corrected and controlled to the satisfaction of the state or local health department and the city, or (2) intricate plumbing and piping arrangements or where entry to all portions of the premises is not readily accessible for inspection purposes, making it impracticable or impossible to ascertain whether or not cross-connections exist.
(Ord. 88-01 § 3(B), 1988)
The type of protection that shall be provided to prevent back-flow into the approved water supply shall be commensurate with the degree of hazard that exists on the consumer’s premises. The type of protective device that may be required (listing in an increasing level of protection) includes double check valve assembly (DC), reduced pressure principle backflow prevention device (RP), and an air-gap separation (AG). The water user may choose a higher level of protection than required by the city. The minimum types of backflow protection required to protect the approved water supply at the user’s water connection to premises with varying degrees of hazard are given in Table 1. Situations which are not covered in Table 1 shall be evaluated on a case-by-case basis and the appropriate backflow protection shall be determined by the city or health agency.
Table 1
TYPE OF BACKFLOW PROTECTION REQUIRED
Degree of Hazard
Minimum Type of Backflow Prevention
A.
Sewage and Hazardous Substances.
 
1.
Premises where the public water system is used to supplement the reclaimed water supply.
AG
 
2.
Premises where there are wastewater pumping and/or treatment plants and there is no interconnection with the potable water system. This does not include a single-family residence that has a sewage lift pump. An RP may be provided in lieu of an AG if approved by the health agency and the city.
AG
 
3.
Premises where reclaimed water is used and there is no interconnection with the potable water system. An RP may be provided in lieu of an AG if approved by the health agency and the city.
AG
 
4.
Premises where hazardous substances are handled in any manner in which the substances may enter a potable water system. This does not include a single-family residence that has a sewage lift pump. An RP may be provided in lieu of an AG if approved by the health agency and the city.
AG
 
5.
Premises where there are irrigation systems into which fertilizers, herbicides or pesticides are, or can be, injected.
RP
B.
Auxiliary Water Supplies.
 
1.
Premises where there is an unapproved auxiliary water supply which is interconnected with the public water system. An RP or DC may be provided in lieu of an AG if approved by the health agency and the city.
AG
 
2.
Premises where there is an unapproved auxiliary water supply and there are no interconnections with the public water system. A DC may be provided in lieu of an RP if approved by the health agency and the city.
RP
C.
Fire Protection Systems.
 
1.
Premises where the fire system is directly supplied from the public water system and there is an unapproved auxiliary water supply on or to the premises (not interconnected).
DC
 
2.
Premises where the fire system is supplied from the public water system and interconnected with an unapproved auxiliary water supply. An RP may be provided in lieu of an AG if approved by the health agency and the city.
AG
 
3.
Premises where the fire system is supplied from the public water system and where either elevated storage tanks or fire pumps which take suction from the private reservoirs or tanks are used.
DC
D.
Dockside Watering Points and Marine Facilities.
DC
 
1.
Pier hydrants for supplying water to vessels for any purpose.
RP
 
2.
Premises where there are marine facilities.
RP
E.
Premises where entry is restricted so that inspections for crossconnections cannot be made with sufficient frequency or at sufficiently short notice to assure that cross-connections do not exist.
RP
F.
Premises where there is a repeated history of cross-connections being established or reestablished.
RP
G.
Two or more services supplying water from different street mains to the same building, structure or premises through which an interstreet main flow may occur, shall have at least a standard check valve on each water service to be located adjacent to and on the property side of the respective meters. Such check valve shall not be considered adequate if backflow protection is deemed necessary to protect the city’s mains from pollution or contamination; in such cases, the installation of approved backflow devices at such service connections shall be required.
 
(Ord. 88-01 § 3(C), 1988)