Cross-connection control management is a complex job.

Our Backflow Academy is here to help answer your questions.

What is Backflow?

Typically, water will flow from the public water supply to the consumer’s plumbing distribution system. Backflow is the undesirable reversal of this flow of water and undesirable substances from the non-potable source to the potable source.

What is Cross-connection?

A cross-connection is any actual or potential connection between the public or consumer’s potable water system and any non-potable source or substance that present a hazard to the quality of the public or consumer’s potable water system. Therefore, cross-connection control is the management or “control” of these cross-connections to protect public safety by preventing backflow incidents within the public or water consumer’s potable water system.

How are cross-connections protected to prevent backflow incidents from occurring?

Cross-connections are protected either through containment or isolation. Ideally, for an effective cross-connection control program, there will be a mix of both containment and isolation protection working in correlation.

  • Containment is cross-connection protection located at the consumer’s water service or meter. This level of protection contains the entire facility and protects the public water supply from the consumer’s plumbing system. However, it does not provide cross-connection protection internally within the facility.

  • Isolation is cross-connection protection located within the water consumer’s facility and isolates the hazard at the point of use. This protects the individuals within a facility from contamination or pollutant hazards from entering their internal plumbing system.

a diagram of a backflow event and how it could happen

Are all backflow incidents the same?

No, depending on the non-potable source or what the substance is, cross-connections are generally classified as high hazard or low hazard. Since there is no consensus, standards for defining and differentiating between a high and low hazard, each state (and on occasion the local public water supply) will define for themselves the criteria for each hazard. However, there is a commonality among the definitions.

What causes backflow incidents to occur?

Backflow incidents are caused by either backpressure or backsiphonage.

  • Backpressure is created when the pressure within the customer’s system becomes greater than the water supply pressure. Elevated tanks, heating systems and booster pumps are some of the main causes of backpressure.

    Backsiphonage is created when there is a negative or reduced pressure in the water supply main. Water main breaks or hydrant flushing are two of the main causes of backsiphonage.

Backflow Assembly Testing FAQ

Can anyone test a backflow assembly?

No! Backflow assemblies must be tested by qualified individuals who have obtained the proper certifications pertaining to cross-connection and backflow assembly testing procedures. Each state (or possibly the local jurisdiction) establish their own criteria and procedures for issuing certifications. Along with the state issued certifications, several industry trade associations (USCFHRR, ASSE, TREEO, ABPA) offer training courses and certifications in the proper techniques for testing backflow prevention assemblies.

What happens if the backflow assembly fails a test? Do they have to be repaired?

Yes! If a backflow assembly fails the test and does not meet standard, the assembly must be repaired. The water purveyor determines the time required to have the repairs made. The plumbing code and cross-connection regulations will specify what the qualifications and credentials are that may be required for the individual performing the repair.

How often is testing required?

Manufacturers of backflow assemblies and most regulating authorities require annual testing. Backflow assemblies are a mechanical device. Just like maintenance on a car with regular oil changes, a backflow assembly has to be checked to ensure it is functioning properly.

Which backflow method is used?

The only sure method is by having qualified personnel out in the field conducting field facility surveys and plumbing inspections to identify cross-connections.  These individuals must be knowledgeable in all things cross-connection, including identifying plumbing arrangements, identifying hazards, determining the hydraulic conditions, determining the level of hazard present, and determining the appropriate backflow prevention method.  Supported by state and local authorization and ordinances, only then can the inspector make the appropriate determination.

How is a backflow assembly tested?

A qualified professional in your jurisdiction will utilize a Backflow Preventer Test Kit. The Backflow Preventer Test Kit is a compact portable device that measures differential pressure and is used for all testing of backflow prevention assemblies, i.e. DCVA, RP, PVB and SVB types. Depending on the model, test kits come equipped with either 3 or 5 soft seated needle valves. Equipped with a full-face scale, the kit can measure a range of 0-15 psid (psi differential). Test kits are equipped with three color-coded service hoses with inline filters for connecting the test kit to the backflow prevention assembly.

How to Prevent Backflow Incidents

Backflow prevention methods can be implemented either at the service meter, called containment protection, or at the point of water use at the fixture, called isolation protection. These backflow prevention methods can be divided into 4 basic categories – elimination, backflow devices, backflow assemblies, and air gap.

Air Gap

The vertical, unobstructed space between the free flowing end of the potable water supply pipe and the flood level or overflow rim in a non-pressure receiving fixture, device, or container to which the public water is supplied. The air gap shall be at least 2x the diameter of the water inlet piping with a minimum of 1 inch. In some localities, an air gap is not to exceed 12 inches. One drawback with an air gap is that the city water supply pressure is lost. The water customer must either use gravity or a booster pump to regain system pressure to move water from the holding tank to its intended point of use.

Elimination

Eliminating the cross-connection is necessary when the hazard has been improperly installed and plumbed, or when the hazard is simply no longer in use.

Backflow Device

Mechanical units are used for backflow prevention. They do not have inlet or outlet shutoff valves and usually do not have test cocks. For devices without test cocks, inline testing is not possible. Devices also do not hold USC approval.

Backflow Assemblies

Another mechanical unit used for backflow prevention. They are different from devices because they do come equipped with inlet and outlet shutoffs, as well as test cocks for testing purposes.

Who has responsibility for an approved and effective cross-connection control program?

EVERYONE!

The water purveyor, local plumbing authority, water consumers and all individuals performing backflow prevention assembly installation, testing and repairs have some level of responsibility for ensuring an effective cross-connection control program.

  • Develop an approved ordinance to govern the program in accordance with state cross-connection guidelines or regulations.

  • On-site facility surveys to make the proper determination of hazard and method of protection required.

  • Document and maintain all records pertaining to the field surveys.

  • Maintain an accurate inventory of all backflow assemblies, and in some jurisdictions, backflow devices.

  • Developing a testing schedule of all testable backflow assemblies.

  • Notifying the water consumer when assemblies are due for testing.

  • Retain all assembly test reports.

  • Non-compliance enforcement action.

The individuals performing backflow prevention assembly installation, testing and repairs are responsible for following all codes and regulations as outlined by the local cross-connection control program.  This should include the following:

  • Holding all necessary and required credentials to properly install, test and maintain backflow assemblies.

  • Ensuring backflow assembly testing equipment is calibrated and working properly.

  • Testing the backflow assemblies in accordance with the proper testing procedures.

  • Repairing backflow assemblies in accordance with manufacturer’s authorized repair procedures.

  • Properly identifying and documenting all backflow assembly information such as hazard, size, make, model, serial number, location, etc.

  • Documenting the results of the backflow assembly test.

  • Submitting test reports to the water purveyor within the required time frame.

  • Provide to the water consumer a copy of the test results for their records.

The local plumbing authority is responsible for implementing and enforcing the local plumbing codes. The water consumer is responsible for preventing unprotected cross-connections and maintaining protected cross-connections within the water consumer’s facility.  This should include the following:

  • Maintaining backflow devices ensuring cross-connections do not pose a risk to the water distribution system.

  • Ensuring backflow assemblies are tested and maintained according to the testing schedule of the water purveyor by hiring qualified personnel in accordance with the local jurisdiction’s criteria.

Do backflow incidents really happen?

Yes!

Click here for a list of documented backflow incidents from the TREEO Center.