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Frequently Asked Questions

Peterborough Utilities Commission is responsible for providing safe, clean water to the citizens of Peterborough. There are many ways in which the quality and safety of the public water supply may be compromised however. Cross connections represent one of the most frequent means of affecting water quality.

What is a cross-connection?

A cross-connection is any actual or potential connection between a potable (drinking) water system and any source of pollution or contamination.

What does a typical cross-connection look like?

A common example is a garden hose connected to a hose bibb at one end and the other end of the hose lying in a pool, puddle or any other source of non-potable water. Another example would be the make up water for a hot water heating boiler. The water in these systems can be rusty and oily and could pose a health threat if consumed.

Are there any other common types of cross-connections?

Yes. Some common cross-connections found in plumbing and water systems include:

  • A water softener drain or other type of water conditioning equipment directly connected to a sanitary sewer,
  • A chemical sprayer attached to a hose without a backflow preventer,
  • A high pressure washer utilizing soaps or cleaners connected to a hose bib or other source of water without a backflow preventer,
  • A lawn irrigation system installed without an approved type of backflow preventer,
  • Using a hose to unplug blocked toilets and sewers,
  • Photo developing equipment,
  • An auxiliary water supply connected to a municipal supply,
  • A toilet that does not have an anti-siphon float valve installed.

What is backflow?

Backflow is a flowing back of water or reversal of the normal direction of flow. Backflow may occur due to either back siphonage or back pressure.

What is back siphonage?

Back siphonage is backflow caused by a negative pressure (i.e., a vacuum or partial vacuum) in a public water system. The effect is similar to drinking water through a straw. Back siphonage can occur when there is a stoppage of water supply due to nearby fire fighting, a break in a water main, high velocities in pipe lines, line repair or break that is lower than a service point, lowered main pressure due to high water withdrawal rate such as fire fighting or water main flushing or reduced supply pressure on the suction side of the booster pump.

What is back pressure?

Back pressure is pressure that is greater than the municipal water system supply pressure. It can happen when there is a connection to a non-potable supply operating at a higher pressure than the water distribution system. Increases in pressure can be created by booster pumps, temperature increases in boilers, interconnections with systems operating at higher pressures and elevated piping (e.g., 30’ above finished grade).

What causes backflow?

An example is when there is a water main break and the area must be isolated and repaired. When the valves around the repair site are closed, the flow of water is stopped to all points of use such as homes and businesses and begins to flow backwards towards the repair. This is back siphonage and if there are cross connections, contaminants can be drawn into the water system.

What happens after backflow occurs?

When the repair is completed and the regular pressure is restored everything starts to flow in the proper direction. Any contaminants that had a chance to enter the water supply will start to flow towards any point of use (plumbing fixtures) in homes or businesses. The degree of hazard to health will be dependant on the type and amount of contaminant, the amount of time the situation goes unnoticed and whether or not a protective device is in place.

Why do water purveyors need to control cross-connections and protect their public water systems against backflow?

Backflow into a public water system can pollute or contaminate the water in that system. The hazard created by backflow is generally identified in three groups: severe or high, moderate and minor. A severe hazard is likely to result in serious injury or death while a minor hazard may simply affect the colour, odour or taste of the water with little or no health affects. Each water purveyor has a responsibility to provide water that is usable and safe to drink under all foreseeable circumstances. Further, the expectation of the public is that water quality supplied by the water purveyor is potable and safe to use and it will remain so regardless of its use. For these reasons, each water purveyor must take reasonable precautions to protect its public water system against backflow.

What should a water purveyor do to control cross-connections and protect their public water systems against backflow?

A water purveyor should ensure that a proper backflow preventer is installed and maintained at the water service connection to each system or premises that poses a hazard to the public water system (premise isolation). Generally, this would include water service connections to each dedicated fire protection system or irrigation piping system; premises with an auxiliary or reclaimed water system; industrial, medical, laboratory, marine or other facilities where objectionable substances are handled in a way that could cause pollution or contamination of the public water system; premises exempt from Part 7 (Plumbing) of the Ontario Building Code and premises where an internal backflow preventer required under the Ontario Building Code is not properly installed or maintained; classified or restricted facilities; and tall buildings. Zone protection within a facility may be required in addition to premise isolation, a requirement in order to protect users of the facility.

How can backflow be prevented?

The simplest way is to eliminate the cross connection from the water distribution (plumbing) system. Where this is not possible, a backflow preventer (BFP) must be installed. A BFP is a means or mechanism to prevent backflow. The basic means of preventing backflow is an air gap, which either eliminates a cross-connection or provides a barrier to backflow. An air gap is easily circumvented however and is not always the most appropriate type of BFP to use. The basic mechanism for preventing backflow is a mechanical backflow preventer, which provides a physical barrier to backflow. The principal types of mechanical backflow preventer are testable devices such as the reduced-pressure principle assembly, the pressure vacuum breaker assembly, and the double check valve assembly. There are other types of BFP’s available for secondary types of protection that are not testable.

What is an air gap?

Air GapAn air gap is a vertical, physical separation between the end of a water supply outlet and the flood-level rim of a receiving vessel. This separation must be at least twice the diameter of the water supply outlet and never less than one inch. An air gap is considered the maximum protection available against backpressure backflow or backsiphonage but is not always practical and can easily be bypassed.

What is a reduced pressure principle assembly (RP)?

Reduced PressureAn RP is a mechanical backflow preventer that consists of two independently acting, spring-loaded check valves with a hydraulically operating, mechanically independent, spring-loaded pressure differential relief valve between the check valves and below the first check valve. It includes shutoff valves at each end of the assembly and is equipped with test cocks. An RP is effective against back pressure and back siphonage and may be used to isolate health or non-health hazards. The device is designed for use under continuous pressure.

What is a pressure vacuum breaker assembly (PVB)?

Pressure Vacuum BreakerA PVB is a mechanical backflow preventer that consists of an independently acting, spring-loaded check valve and an independently acting, spring-loaded, air inlet valve on the discharge side of the check valve. It includes shutoff valves at each end of the assembly and is equipped with test cocks. A PVB may be used to isolate health or non-health hazards but is effective against backsiphonage only. The device is designed for use under continuous pressure.

What is a double check valve assembly (DCVA)?

Double Check Valve AssemblyA DCVA is a mechanical backflow preventer that consists of two independently acting, spring-loaded check valves. It includes shutoff valves at each end of the assembly and is equipped with test cocks. A DCVA is effective against back pressure and back siphonage but should be used to isolate only non-health hazards. The device is designed for use under continuous pressure.

Why do backflow prevention devices have to be tested periodically?

Mechanical BFPs have internal seats, springs and moving parts that are subject to fouling, wear or fatigue. Mechanical BFPs and air gaps can also be by passed. Therefore, all BFPs have to be tested periodically to ensure that they are functioning properly. A visual check of air gaps is sufficient, but other devices have to be tested with properly calibrated gauge equipment.

Where can I get more information about cross connection control?

CAN/CSA-B64.10-07 CAN/CSA-B64.10.1-07 Standard, Manual for the Selection and Installation of backflow Prevention Devices/Manual for the Maintenance and Field Testing of Backflow Prevention Devices; Ontario Building Code- Part 7 Plumbing or the American Water Works Association's (AWWA) Manual M14, Recommended Practice for Backflow Prevention and Cross-Connection Control, EPA's Cross Connection Control Manual.

Who is required to comply with these new regulations?

The Cross Connection Control Program (CCCP) applies to all Industrial, Commercial and Institutional (ICI) properties as well as many home businesses. The registered owner of the property is ultimately responsible for the upgrade of their water distribution system. The Authorized Functions List in the CCCP should be consulted for information on who can do what.

Who is responsible for the testing and maintenance of the backflow prevention device?

It is up to the customer/property owner to ensure that the BFP is properly maintained and repaired, tested at the time of installation and on an annual basis thereafter. If any maintenance or repairs are performed on the device, it must be re-tested. The BFP is the property of customer/property owner and therefore they are responsible for any damage or repairs to the device. At the time of ownership change, re-zoning or process changes, a new survey will be required for the premises.

What do I need to do to get into compliance with the CCCP?

The first step is to contact a registered tester and have a survey done of your water distribution system. Your tester will complete a Peterborough Utilities Commission Cross Connection Survey Report and submit it to the Cross Connection Control Officer for review. We will review the survey to ensure that the correct choices have been made for the appropriate hazards while checking that there is no 'over-protection' recommended. This is to ensure that the customer only gets what they need for compliance. A copy of the "approved" survey will be returned from our office to the customer with a letter stating that the review is complete and that the upgrades recommended, when implemented, will achieve compliance with the CCCP. The next step is to have a certified plumber, licensed to work in the City of Peterborough, take out a permit and perform the necessary upgrades. When the work is complete, a final on-site inspection will confirm compliance with the CCCP. A 'Final Clearance Letter' will be sent to the owner and the property will be entered into our backflow device management system. A reminder letter will be sent to the customer approximately one year later to have the annual test completed.

What is a survey and who can perform the survey?

A survey is an inspection of a facility to determine whether or not there are any existing or potential cross-connections that must be isolated from the water distribution system. Only persons that have been qualified as a tester of backflow prevention devices and who holds a valid Backflow Prevention Certificate issued by the AWWA or approved equivalent and who has registered with the PUC may perform the survey.

Who can test backflow prevention devices?

Just as the person that performs a survey, a tester must be qualified as a backflow prevention device tester through the AWWA or approved equivalent and they must be registered as a tester with the PUC. A list of persons registered as a tester of backflow prevention devices is kept by the PUC and qualifications are checked annually.

What is zone isolation?

Zone isolation is isolation of water located within an area of a facility from any potable water system located within the facility. While protection of the municipal supply system is imperative it is equally important to protect the users of a building from certain types of procedures or activities taking place within the facility. An example would be an industrial user of chemicals utilizing high pressure for a procedure that could contaminate areas of the building that must have potable water such as kitchens, cafeterias, drinking fountains, eye wash stations and washrooms. Laboratories, funeral homes and boiler systems utilizing chemicals are some other examples of activities requiring additional protection within a building.

What is premise isolation?

Premise isolation is preventing backflow into a public water system from a user’s premises by installing a suitable backflow-prevention device at or near the building control valve or water meter. Premise isolation for a building shall be required even if the water distribution system in the building conforms to current Ontario Building Code requirements because backflow into the public water supply can still occur if the individual protection fails.

Two levels of protection shall be recognized for premises isolation as follows:

  1. Premises with a moderate hazard classification shall be isolated by a DCVA backflow preventer. The following are examples of buildings or facilities that shall be isolated from the water supply by a DCVA backflow preventer:
    • Office buildings
    • Multi-service interconnected facilities
    • Schools and colleges
    • Shopping malls
    • Multi-tenant single service facilities
    • Premises with sprinkler systems (no glycol)

  2. Premises with a severe hazard classification shall be isolated with a RP backflow preventer. The following are examples of buildings or facilities that shall be isolated from the water supply by a RP backflow preventer:
    • Hospital, operating, laboratory, or mortuary facilities
    • Plants using radioactive material
    • Petroleum processing and storage facilities
    • Chemical or plating plants
    • Commercial laundries
    • Sewage treatment plants
    • Food and beverage processing plants
    • Premises where access is restricted
    • Dockside facilities for ships
    • Premises with sprinkler systems (glycol loop)

NOTE: These lists should not be considered as complete. Each building shall be classed depending on its use.

What can I do?

Drinking water quality standards are becoming increasingly more stringent. The need to protect this valuable and limited resource is everyone’s responsibility; it is not limited to Peterborough Utilities Commission. Water education, preservation and conservation must be a goal for everyone. The elimination of cross connections is one way to achieve this goal. If you suspect you may have a cross connection or you have any questions please contact Dave Young, Cross Connection Control Officer, at 705-748-9301, extension 1349 or at