A cross connection is a real or potential connection between the drinking water supply and any source of contaminant.
Improper plumbing or cross connections on private property can contaminate the public drinking water supply. If there is an incident which results in contamination of public drinking water, the owner responsible or occupant of the property can be held liable for damages.
Frequently Asked Questions About Cross Connection Control
What is a cross connection?
A cross connection is a piping arrangement which allows the potable water supply to be connected to a contaminant source. The most common example is a garden hose attached to a sill cock with the end of the hose connected to a pesticide sprayer. A drop in water pressure can cause these chemicals to be pulled back into the water supply (backflow), contaminating a building or even a neighbourhood. The contaminant then poses a risk for anyone using the water for drinking, cooking, bathing, or other purposes.
What is potentially dangerous about an unprotected sill cock?
The purpose of a sill cock is to permit easy attachment of a hose for outside watering purposes. However, a garden hose can be extremely hazardous because they are left submerged in swimming pools, laying in elevated locations watering shrubs, attached to chemical sprayers, etc.
What protection is required for sill cocks?
A hose bibb vacuum breaker should be installed on every sill cock to isolate garden hose applications thus protecting the potable water supply from contamination.
What is a Cross Connection Control Program?
A Cross Connection Control Program is a cooperative effort between plumbing and health officials, water purveyors, property owners and certified testers to establish and administer guidelines for controlling cross connections and implementing means to ensure their enforcement so that the public potable water supply will be protected. The elements of a program define the type of protection required, the responsibility for the administration and enforcement, and a public education and communications plan.
What is the difference between pollution and contamination?
Pollution of the water supply does not constitute an actual health hazard, although the quality of the water is impaired with respect to taste, odor or utility. Contamination of the water supply, however, does constitute an actual health hazard: the consumer being subjected to potentially lethal water borne disease or illness.
What is meant by "Degree of Hazard"?
The degree of hazard is a commonly used phrase utilized in cross connection programs and is simply a determination on whether the substance in the non-potable system is toxic (health hazard) or non-toxic (non-health hazard). There are three degrees of hazard; severe, moderate and minor. For more information on hazard classification refer to the WCS AWWA Cross Connection Manual.
What is the difference between a toxic and a non-toxic substance?
Toxic substance is any liquid, solid or gas, which when introduced into the water supply creates, or may create a danger to health and well-being of the consumer. A non-toxic substance is any substance that may create a non-health hazard, is a nuisance or is aesthetically objectionable. Backflow prevention devices must be selected in accordance with the type of connection and degree of hazard.
Should we be concerned?
Yes, to cause a situation that has the potential to harm the health and well being of your family, co-workers, or neighbours, should be a concern to us all. A cross connection in a home, place of business is a danger to those in the surrounding community. You have a legal and moral responsibility to ensure that our drinking water supply is safe. If you need to know more about Cross Connection control contact a Committee Member near you.
Are there any regulations related to Backflow or Cross Connection conditions?
Plumbing codes have always prohibited any connection whereby potable and non-potable water could mix. The Canadian Plumbing Code Committee continue to work on revising subsection 6.2 "Protection From Contamination".
What type of reference material is available?
The Western Canada Water & Wastewater Cross Connection Control Manual, CAN/CSA-B64.10-94, EPA's Cross Connection Control Manual, and AWWA's M14 Manual are excellent reference manuals for establishing a cross connection control program or for further information on cross connection control.
What are the five basic products used for protection of cross connections?
The five basic products are: Air Gap, Atmospheric Vacuum, Pressure Vacuum Breakers, Double Check Valve Assembly, Reduced Pressure Backflow Preventers.
What is an Air Gap?
Air Gap is the physical separation of the potable and non-potable system by an air space. The vertical distance between the supply pipe and the flood level rim should be two times the diameter of the supply pipe, but never less that 1". Air gaps are frequently used on wash basins and industrial processing applications.
Where is an Atmospheric Vacuum Breaker used?
Atmospheric Vacuum Breakers may be used only on connections to a non-potable system where the vacuum breaker is not subjected to back-pressure and must be installed on the discharge side of the last control valve and above the usage point. A Atmospheric Vacuum Breaker it not to be used under continuous pressure. Typical applications for an Atmospheric Vacuum Breaker are lawn sprinkler systems and dishwashers.
Where is an Hose Bibb Vacuum Breaker used?
Hose Bibb Vacuum Breaker are small inexpensive devices for hose connections which are simply attached to sill cocks, and threaded faucets. However, like the Atmospheric Vacuum Breaker they should not be used under continuous pressure. Hose Bibb Vacuum Breakers are commonly used on sill cocks, services sinks and any threaded pipe to which a hose may be attached.
Where is a Pressure Vacuum Breaker used?
Pressure Vacuum Breakers may be used as protection on connections to all types of non-potable systems where they are not subject to back-pressure. These units must be installed above the usage point and may be used under continuous supply pressure. The applications for a Pressure Vacuum Breaker are similar to the Atmospheric Vacuum Breaker with the exception that they may be used under continuous pressure.
Where is a Double Check Valve Assembly used?
A double check valve assembly may be used as protection of all direct connections through which any substance might enter the potable water system in a concentration which would constitute a nuisance or be aesthetically objectionable, such as air, steam, food, or other material which does not constitute a health hazard. The Double Check Valve Assembly is used where the degree hazard is low.
Where is a Reduced Pressure Principle Backflow Assembly used?
A Reduced Pressure Principal Backflow Assembly may be used on all direct connections which may be subject to backpressure or back-siphonage, and where there is the possibility of contamination that constitute a potential health hazard. A Reduced Pressure Principle Backflow Preventer is used whenever the non-potable source is more of a contaminate such as boiler feed lines. The Reduced Pressure Principal Backflow Assembly is used where the degree of hazard is severe.
What is the benefit of a strainer preceding a backflow assembly?
A strainer will protect the check valves of a backflow preventer from fouling due to foreign matter and debris which may be flowing through the line. This not only protects the assembly but eliminates nuisance fouling and subsequent maintenance and shutdown. The use of a strainer with a water pressure reducing valve has been an accepted practice for years. Strainers should not be used in fire protection systems unless approved by the authority having jurisdiction.
For more information contact EPCOR Cross Connection Control Program:
Phone: (780) 412-6888
Fax: (780) 412-7717
Copyright © 2003 Western Canada Section AWWA. All rights reserved.