OAK LODGE WATER DISTRICT

Definitions

"Air Gap Separation" means the physical vertical separation between the free flowing discharge end of a potable water supply pipe line and the open or non-pressure receiving vessel.

"Approval" or "Approved" means approved in writing.

"Atmospheric Vacuum Breaker (AVB)" means a device consisting of an air inlet valve, a check seat and an air inlet port(s).

"Auxiliary Water Supply" means any supply of water used to augment the supply obtained from the public water system which serves the premises in question.

"Backflow" means the flow in the direction opposite to the normal flow caused by backsiphonage or back pressure. Backsiphonage is caused by negative or reduced pressure in the supply piping and back pressure occurs when the potable supply piping is connected to a system or fixture which exceeds the operating pressure of the supply piping.

"Backflow Preventer" means an airgap, AVB, PVBA, SVBA, DCVA or RPBA.

"Backflow Prevention Assembly" means a backflow prevention device such as a pressure vacuum breaker, spill resistant pressure vacuum breaker, a double check valve or a reduced pressure principle device, and the attached shut off valves on the inlet and outlet ends of the device assembled as a complete unit.

"Check Valve" means a valve which allows flow in only one direction.

"Community Water System" means a public water system which has 15 or more service connections used by year-round residents, or which regularly serves 25 or more year-round residents.

"Cross Connection" means any link or channel between the piping which carries drinking water and the piping or fixtures which carry other water or other substances.

"Division" means the Health Division of the Oregon Department of Human Resources.

"Double Check Valve Assembly (DCVA)" means an assembly of two independently acting check valves with shut-off valves on each side of the check valves and test cocks for checking the water tightness of each check valve.

"Non-Transient Non-Community Water System (NTNC)"means a public water system that is not a Community water system and that regularly serves at least 25 of the same persons over 6 months per year.

"Pressure Vacuum Breaker Assembly (PVBA)" means an assembly consisting of an independently operating, internally loaded check valve and an independently operating loaded air inlet valve located on the discharge side of the check valve.

"Reduced Pressure Backflow Assembly (RPBA)" means a device for preventing backflow which has two check valves, a differential relief valve located between two check valves, two shut-off valves, one on the upstream side and the other on the downstream side of the check valves, and four test cocks for checking the watertightness of the check valves and the operation of the relief valve.

"Service Connection" means the piping connection by means of which water is conveyed from a distribution main of a public water system to a user's premises. For a Community water system, the portion of the service connection which conveys water from the distribution main to the user's property line, or to the service meter where provided, is under the jurisdiction of the water supplier.

"Spill Resistant Pressure Vacuum Breaker Assembly (SVBA)" is one type of Pressure Vacuum Breaker Assembly.

"Transient Non-Community Water System" means a public water system which serves a transient population of 25 or more persons.

What is back-siphonage backflow and what can cause it? Back-siphonage backflow Is the reversal of normal flow in a system caused by negative pressure (a vacuum or partial vacuum) in the supply piping.  Back-siphonage backflow can be created when a stoppage occurs in the water supply. This may happen in a public water system because of nearby fire fighting, repairs or breaks in the main water supply line. The effect is similar to the sipping of an ice cream soda through a straw. The liquid is drawn into the low pressure (suction) area.	What is back-pressure backflow and why does it occur? Back-pressure backflow is the reversal of normal flow in a system because downstream pressure is greater than the supply pressure.  Back-pressure backflow occurs when the higher pressure in the user system pushes undesirable substances back into the water supply system. Causes can be booster pumps, the backflow from an elevated irrigation system back to the well head when the pump is shut down, or the siphonage from a spray tank back through the fill hose to the supply line when the water supply pressure is lost or the pump is turned off.
What is a cross-connection? A cross-connection is a direct or indirect arrangement of piping that allows the potable water supply to be connected to piping that contains a contaminant. An example is the common garden hose attached to a water spigot with the end of the hose lying in a puddle of water. Other examples are a hose attached to a service sink with the end of the hose submerged in a tub full of detergent, supply lines connected to bottom-fed tanks (such as pesticide spray tanks or fermentation tanks) and supply lines to boilers.	What are some basic devices commonly used for protection against cross-connections? Common devices are:  Air gap.  Atmospheric vacuum breakers (AVB), including hose connection vacuum breakers.  Pressure-type vacuum breakers (PVB).  Double-check valves (various arrangements). Reduced pressure zone assembly.
What are hose bibb vacuum breakers and where are they used? Hose bibb vacuum breakers are small, inexpensive devices with hose connections that simply attach to water spigots, threaded faucets or other fixtures where a hose could be attached that could be introduced to a contaminant. Like the atmospheric-type vacuum breaker, they should not be used under continuous pressure (i.e., with a downstream valve) nor be subject to back-pressure backflow conditions.	Selecting the proper backflow prevention device Backflow prevention devices are available in a wide range of types and styles. They range from small, simple units to large, complex assemblies. The selection of the most appropriate device depends on the particular situation. Pesticides are considered a health hazard and require a device that will protect the water supply from high hazard conditions and materials. Exercise considerable care when selecting a device. Any device selected to protect the potable water supply from cross-connection backflow contamination must be approved for use by the state and meet local and state plumbing codes. Additional help in developing suitable cross -connection controls is available from experienced licensed plumbers, representatives of the manufacturers of approved backflow prevention devices, your local supplier or the water district.