Backflow Education

What is backflow?

Backflow is defined as the reverse flow through a cross-connection from a possible source of contamination back into the potable (i.e., drinking) water supply system.

In essence, backflow occurs when a cross-connection causes the pressure in a piping system to reverse, which then causes the normal direction of flow to reverse—meaning that the flow materials go the wrong way through the pipes. Pressure reversals can be classified as either backsiphonage or backpressure.

What is a potable water supply?

Potable water, also known as drinking water, comes from ground and surface sources and is treated to levels that meet state and federal standards.

What is a cross-connection?

A cross-connection is any type of physical connection between a possible source of contamination and a drinking water pipe system, which automatically creates the risk of backflow.

What causes backsiphonage?

Backsiphonage involves a loss of pressure in a piping system that results in backflow. This can occur if drinking water supply pressure is either lost or decreases to a level that is lower than the pressure of a cross-connected contamination source. Given that matter moves from high pressure to low pressure by nature—the same science that makes vacuum cleaners and drinking straws work—this causes contamination source materials to be “siphoned,” or pulled, back into the drinking water pipe system.

What causes backpressure?

Backpressure involves a cross-connected contamination source applying a pressure against the drinking water supply that is higher than the drinking water supply’s own pressure, essentially pushing contaminants into the drinking water supply. Any cross-connections that include pumping systems (e.g., well pumps) or pressurized systems (e.g., steam or hot water boilers) can create backpressure and cause contaminant backflow into the drinking water supply.

Why be concerned about cross-connections and backflow?

All cross-connections pose a potential health risk of contaminant backflow into the drinking water system. Backflow can be a health hazard if contaminants enter your potable water supply, as contaminated water can be dangerous if consumed or used for bathing. Cross-connection backflow can cause chemical burns, fires, explosions, poisonings, illness, and even death.

What can I do to prevent backflow?

• Avoid creating any cross-connections between auxiliary water systems (i.e., wells, cisterns, bodies of water) and drinking water system pipes. If you suspect an existing cross-connection, please contact the North Canton Water Treatment Plant at 330-499-8223, option 8.

• Install approved, testable backflow preventers wherever required, and ensure they are kept in working order.

• Maintain air gaps by ensuring that hoses are not submerged or placed in areas where they could become submerged while connected.

What are some examples of plumbing installations where backflow prevention assemblies are required?

Backflow prevention assemblies are required for irrigation systems (i.e, outdoor sprinkler systems), commercially leased property, full-service restaurants, medical facilities, mortuaries, convalescent homes, lavatories, car washes, automotive repair shops, industrial sites, swimming pools, and any property that has a second source of water available in addition to the drinking water supply, such as a well pond or other auxiliary storage.

When backflow protection is required, the consumer must provide and maintain the assembly or assemblies at their own cost. Failure to do so poses a risk to the public and may necessitate the Utility Billing Department shutting off water to a property with an unprotected service line.

It is the policy of the City of North Canton to require that all businesses have the minimum of a double-check valve assembly backflow installed for containment purposes. If the business is determined to pose a more significant backflow hazard, a reduced pressure principal assembly must be installed as required by the Ohio Administrative Code. These assemblies are to be inspected annually by a plumber with a DOC backflow certification at the expense of the water consumer.

Backflow assembly installation

Backflow assemblies must be installed by a plumber with a DOC Backflow Certification. It is also a requirement that the plumber be an actively registered contractor in the City of North Canton and that a permit be issued for the work. Contact the City of North Canton Permits Department at 330-499-8223, option 7 to complete annual contractor registration with the City or to obtain a City permit.

Annual testing of backflow prevention assemblies

Backflow prevention assemblies are mechanical devices. Like any mechanical device, they are prone to malfunction due to age, use, manufacturing defects, etc. When a backflow prevention device is required, it must also be tested by an approved plumber or contractor at least once every twelve (12) months to ensure that it continues to function within accepted ranges. For listings of testers approved to test backflow prevention assemblies within the North Canton water service area, contact bsionline@backflow.com or call 1-800-494-4900.

Information Source: Ohio Environmental Protection Agency (EPA) Backflow Prevention and Cross-Connection Control