Backflow Prevention / Cross-Connection Control

General Information

The Town of Apex Water Resources Department is continually looking for ways to increase efficiency and properly allocate resources while managing the requirements of the Town's backflow prevention / cross connection control program. One of the primary ways we accomplish this is by utilizing the services of BSI Online, a internet based third party contractor, to track backflow assemblies and testers, as well notify testers of expiring certifications and customers of upcoming backflow testing due dates. 

Two notifications (60 days and 30 days prior to due date) are generated and mailed by BSI Online to remind customers of their upcoming backflow testing due date. Approved testers are responsible for uploading the passing backflow test to BSI Online.  The fee to upload each passing backflow test to the BSI Online website is $14.95.  Only passing backflow tests are accepted.  If a test fails, the device will need to be repaired and retested.

When an assembly is past due for testing a Notice of Violation letter is generated by the Town and sent certified mail to inform customers about past due testing and potential enforcement of the Town's Cross Connection Control Ordinance.   

Customers may also utilize BSI Online to view the backflow test information submitted on their behalf by their tester or to download a list of Town approved testers.  The Town approved backflow tester list is updated quarterly on this page.  See forms below to download the list of visit the BSI Online website at and enter the Customer Confirmation Number (CCN) found on the notification letter received from BSI Online or the Town. 

Please visit BSI Online’s website to view information about the organization and how they partner with municipalities all across the US to manage backflow prevention/cross connection programs of all sizes.

Tester Information

Testers please use the Town of Apex Backflow Test Report found at

New Testers
Certified backflow testers may request to be added to the Town's approved backflow tester list by completing the online Cross Connection Control Tester Application form found at  Testers will be required to upload the following information via this application form:

  • Backflow certification
  • Test kit calibration certification
  • NC Plumbing or Fire Sprinkler license, if applicable

Please allow 2 business days for review and approval.  Your name will appear on the approved tester list once you have registered and uploaded a passing backflow test to the BSI Online website.

Tester Re-certification
Testers with expired backflow and/or equipment calibration certifications will be unable to upload passing backflow tests to the BSI Online website until the updated certification information is received by BSI Online.  Testers may submit renewal documentation to BSI Online via the following methods:


Town backflow site survey is below. Backflow preventer surveys will be required for all new installs, certificate of occupancy, change of use, company name change, and ownership change.  

Safe Drinking Water Act

In 1974, Congress passed the Safe Drinking Water Act (SDWA) to protect public health by regulating the nation’s public water supply. Under this law, the Town of Apex (the water purveyor) is prohibited from installing or maintaining a water service connection to a consumer’s water system within its jurisdiction, unless the public potable water supply is protected against backflow by an approved prevention assembly installed at the service connection or point of delivery.


The town goes to great lengths to ensure that the water delivered to citizens is of the highest quality. When water leaves the Apex/Cary treatment plant, it is in its freshest and purest state. However, during delivery, there is a danger that the water may become contaminated or polluted from sources out of our control. This can happen when the water supply main, pipe, or service line is connected to equipment containing a substance not fit for drinking. These cross-connections may be permanent or temporary and have the potential to result in serious illness or even death.


Backflow is the reversal of the flow of water or the mixing of water and other unwanted substances into the water distribution system. Water distribution systems are designed to flow in 1 direction from the main to the customer. When the direction of flow is reversed due to pressure differences such as fire fighting efforts, a water main break, or consumer high-side pressure (pumps), contaminants can enter the potable drinking water system. A single backflow incident can potentially affect hundreds or even thousands of people.


A cross connection is a permanent or temporary piping arrangement between potable water and a non-potable source. Potentially hazardous cross-connections can occur in the following examples:
  • A hose is placed in a bucket of car wash solution while a person is washing their car.
  • Someone uses a garden hose sprayer to apply insecticides or herbicides to their lawn.
  • Someone uses their garden hose to clear a stoppage in their sewer line.
Tube apparatus in the ground used to prevent residential backflow

Backflow Prevention

The Town of Apex administers a cross connection control program to ensure the safety of the drinking water. The Town has developed and implemented an ordinance that requires all industrial, commercial, and irrigation customers to install approved backflow prevention assemblies on their property before branching to a private system. Annual testing of backflow preventers is required.
Metal apparatus used by the town to prevent backflow

Degrees of Hazard

Different types of backflow prevention assemblies are required depending on the degree of hazard.

High Hazard

A high hazard exists when there is danger that a backflow incident could create a health threat. Examples of this classification include:
  • Hospitals
  • Lawn irrigation systems
  • Manufacturing plants where dyes or chemicals are mixed 

Moderate Hazard

A moderate hazard can occur when there is not a health threat, but a backflow incident could cause drinking water to be discolored or have an odor. Retail stores and offices are examples of this classification. Cross-connection control staff evaluate both new and existing customers to determine which hazards, if any, exist and the type of backflow prevention assembly that is required.

Water Hoses

Over half of the nation's cross-connections involve unprotected garden hoses. Without a backflow prevention assembly between your hose and hose-bibb (spigot or outside faucet), the contents of the hose and anything it is connected to (e.g., bucket of sudsy car wash water) can backflow into the piping system and contaminate the drinking water in your own home. Each spigot on your house should have a hose-bibb vacuum breaker installed. This is a simple, inexpensive device which can be purchased at any plumbing or hardware store. Installation is as easy as threading it onto the spigot.