Water normally flows in one direction from the public water system through the customer's cold or hot water plumbing. If the water begins to flow in the opposite direction, due to back pressure or back siphonage, it can become contaminated from cross connection. Backflow can occur in any residential, commercial or industrial property.

Backflow from back siphonage is caused by a negative or sub-atmospheric pressure; a drop in the water main pressure. Events that can cause back siphonage include a water main break or a high rate of water withdrawal, such as firefighting.

Backflow from back pressure is caused when the water system is connected to a system or supply operating at a higher pressure than the municipal water system. A booster pump or elevated piping are examples of connections that operate at a higher pressure that cause back pressure.

Installing a backflow prevention device at the point where the water service enters a building or facility will ensure that Penetanguishene's water distribution system is protected from contamination. 

The Five basic products are:

1. Air Gap
2. Atmospheric Vacuum Breakers – which also includes hose connection vacuum breakers
3. Pressure Vacuum Breakers – which also includes backflow preventer with intermediate atmospheric vent for ½” and ¾” lines.
4. Double Check Valve Assembly
5. Reduced Pressure Zone Assembly.

What is an Air Gap?

An Air Gap is the physical separation of 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 than 1”. The air gap can be used on a direct or inlet connection and for all toxic substances.

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 never subjected to backpressure and is installed on the discharge side of the last control valve. It must be installed above the usage point. It cannot be used under continuous pressure.

Where is a Hose Bibb Vacuum Breaker used?

Hose Bibb Vacuum Breakers are small inexpensive devices with hose connections which are simply attached to sill cocks and threaded faucets or wherever there is a possibility of a hose being attached which could be introduced to a contaminant. However, like the atmospheric Vacuum Breaker they should not be used under continuous pressure.

Where is a Pressure Vacuum Breaker used?

Pressure Vacuum Breakers may be used as protection for connections to all types of non-potable systems where the vacuum breakers are not subject to backpressure. They must be installed above the usage point. (spill resistant models for indoor use are also available).

Where is a Double Check Valve Assembly used?

A double check valve assembly may be used as protection of all direct connections through which foreign material might enter the potable system in 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.

Where is a Reduced Pressure Zone Assembly used?

Reduced Pressure Zone Assemblies may be used on all direct connections which may be subject to backpressure or back-siphonage, and where there is the possibility of contamination by the material that does constitute a potential health hazard.

If an existing facility has more than one water service connection, or has the potential to contaminate the Town's water supply system, the Town may require the owner, at the owner's expense, to conduct a cross connection control survey to evaluate potential risks and cross connections that may allow backflow contamination into the public water supply. The survey shall be conducted and signed by an authorized person, and a copy must be submitted to the Town by the date specified in the Town's notification or within 30 days. A cross connection control survey shall include:

• Number of water service connections with the waterworks;
• Level of hazard for each water service connection;
• Number, type and condition of any existing premise isolation backflow prevention devices'
• Recommended and planned corrective measure(s), if applicable
• Schedule of work required for any corrective measures; and
• Recommendation for appropriate premise isolation backflow prevention device or devices, if applicable, in accordance with the CSA-B64 Standard.

A backflow prevention device may not show visible signs of failure. Backflow prevention assembly devices contain internal seals, springs, and moving parts that are subject to fouling, wear, or fatigue. A backflow prevention assembly device, such as Double Check Valve Assembly (DCVA), or Reduced Pressure Principle Backflow Prevention Assembly, must be tested by a certified individual with a properly calibrated test gauge.

In order to ensure the proper operation of a backflow prevention device, it must be tested upon installation, repair, relocation or replacement, and at least once a year thereafter. 

The owner of the property or building that currently has service connection to the town's water supply or has applied for a new service connection is responsible for the installation of the backflow prevention devices, as well as the annual testing of the device by a certified tester.

Yes, test reports for backflow prevention devices must be submitted on a Town of Penetanguishene Cross Connection Control Testing and Inspection Report