Backflow Prevention / Cross Connection Control

Annual Backflow Preventer Testing

Annual backflow testing is required per the Cross Connection Control Ordinance.  Backflow assemblies are mechanical devices that are subject to failure.  The differential gauge the backflow tester uses during the annual test helps to determine if the backflow assembly is working to prevent backflow and helps to identify what part of the assembly needs repair.

Schedule and Payment

The customer, owner, or property manager is responsible for scheduling and payment of the annual backflow test.  Only Town approved backflow testers may test backflow assemblies.  You can search for Town approved testers on the Town's electronic reporting system managed by our current vendor at


The electronic reporting system only allows passing backflow tests to be submitted.  A failed assembly will need to be repaired, rebuilt or possibly replaced and retested.  The repair/replace and retest should be completed within 10 days for health hazard facilities and 30 days for non-health hazard facilities. Any new or replaced assemblies must be approved lead-free assemblies.  Repairs should be made with lead-free original manufactured parts.


A customer is considered compliant with the Town's Cross Connection Control Ordinance when the backflow tester submits the passing backflow test on your behalf to the electronic reporting system.  The tester is required to submit the test within 10 days of the date of the passing backflow test.

Electronic Reporting System

AquaResource (1)

Effective April 1, 2020 the Town began utilizing the services of TecNXS, Inc. and its electronic reporting system, AquaResource, to track annual backflow testing. A postcard mailed 45 days prior to your annual backflow test due date is generated from the AquaResource site.  The postcard provides your Group ID and the AquaResource Customer Portal web address where you can view your backflow account information, view and print previous backflow tests, view your previous backflow tester information, and update customer contact information that will allow you to receive email notifications of any correspondence generated for your account.  

As a result of the switch to the the AquaResource software the following changes have been implemented:

  • One Pre-Notice will be mailed via postcard generated by AquaResource 45 days prior to the test due date. Notice of Violation letters will continue to be sent certified mail by the Town generated from the AquaResource site.

Please email or phone (919) 372-7478 to obtain your Group ID Number to access your backflow account or if you have any questions regarding the AquaResource site, test due date, or the Town’s Cross Connection Control Program.

We hope you enjoy the following benefits provided through the AquaResource software:

  • The cost for testers to submit a passing backflow test on your behalf has been reduced from $14.95 to $9.75 per test.
  • Customers can add contact information such as phone and email.
  • Customers who elect to add email contact information may choose to have notices sent to their email address in addition to receiving the postcard notification.
  • Customers can view their backflow inventory, see the status of each backflow, and access and print their test reports.
  • Customers can search for Town approved backflow testers from the Portal.

Irrigation Systems

To address water conservation during drought conditions the state passed a new law, General Statute Section 9, Article 38 of Chapter 143 on July 1, 2009, requiring a separate water meter for new in-ground irrigation systems that are connected to local government water systems and large community water systems.

All irrigation systems are required to have a lead-free reduced pressure zone backflow assembly installed per the Town's Cross Connection Control Ordinance and State rules.

Please review the Irrigation Permit Process pamphlet to learn more about installing a new irrigation system.  

Non-Compliant Hose Bibb Irrigation Systems

Hose Bibb irrigation systems are non-compliant with the NC Plumbing Code and the Cross Connection Control Ordinance.  Please review the published article Non-Compliant Hose Bibb Irrigation System to learn why this system is non-compliant.

Deactive Irrigation System

Customers that do not plan to use their irrigation system for a season may submit a Deactivate Irrigation request via the online form found at  The customer will be required to upload a picture to this form showing that the backflow assembly has been removed. If a non-sewer meter is present it will be locked and the backflow account will be made inactive.  When the customer is ready to reactivate their system they will be required to notify the Town via email at and have the backflow assembly tested prior to use. 

Terminate Irrigation System

To permanently remove an irrigation containment assembly, all controls and valves must be removed with the piping capped or plugged below ground near the source of connection. The non-sewer meter box, if existing, shall also be removed.  A plumbing permit is required to cap or plug the piping.  A plumbing permit can be obtained at the Inspections and Permitting Department located at 73 Hunter Street.

Tester Information

New Testers

ATTENTION TOWN APPROVED BACKFLOW TESTERS.  Effective April 1, 2023 the cost to submit passing backflow tests will increase from $9.50 to $9.75, due to price increases in postage, materials, and labor.

Certified backflow testers may request to be added to the Town’s approved backflow tester list by registering on the AquaResource site at If you experience any difficulties or have questions about the site please click on the Help button at the bottom of the AquaResource webpage or visit or you can view step by step directions on How to Register and Submit Passing Backflow Tests.

The AquaResource site is compatible with most browsers with the exception of Internet Explorer and Edge.  School certification and test kit calibration certificates files must be in jpg or png format for upload to the AquaResource site.  

Please allow 2 business days for review and approval. Your name will appear on the approved tester list once you have been approved by the Town. 

Tester Re-certification

Testers with expired backflow and/or equipment calibration certifications will be unable to upload passing backflow tests to the AquaResource site until the updated certification information is uploaded, reviewed, and approved. All certifications/recertifications and licenses must be uploaded via the AquaResource site.  


The backflow site survey found at the link below is required for all new installs, certificate of occupancy, change of use, company name change, and ownership change.

Rules and Ordinance

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’s Permit NC0392045 to operate a community public water system requires the Town to comply with the Rules Governing Public Water Systems (15A NCAC 18C).  The current Cross Connection Control Ordinance (Chapter 12, Article VI), program policies, and standard specifications and details have been written and are administered to comply with these rules to ensure the public potable water system is protected from backflow events and to provide safe drinking water to our customers.

Please visit the Town's Cross Connection Control Ordinance to learn more about our program and what is required to help prevent cross connection and backflow events. 

To learn more about backflow preventer installation requirements please visit the Standard Specifications and Details Section 620.

Cross Connection

A cross connection is any physical connection between a potable water supply system and any other piping system, sewer fixture, container, or device, whereby water or other liquids, mixtures, or substance may flow into or enter the potable water supply system.  The most common causes of residential cross connection hazards are:Cross Connection

  • Garden hoses/hose bibs
  • Lawn irrigation systems
  • Auxiliary water supply (wells)
  • Swimming pools/hot tubs/spas
  • Fire sprinkler systems
  • Boilers

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.

To learn more about the Cross Connection Control Program please view the pamphlet "Cross Connection Control Program"

Degrees of Hazard

A non-potable water source or system can contain liquid, gas, or other substance that can be diluted, dissolved, suspended, or mixed in water and that adversely affects the quality and safety of the water if a backflow should occur.  Non-potable substances can be classified as either moderate or high hazards.  

Moderate Hazard

Locations such as office buildings and small retail stores are considered moderate (non-health) hazards.  Moderate hazards do not affect public health, but they can affect the aesthetic quality of the drinking water.  Biological or chemical pollutants that may enter the public potable water supply in the event of backflow can cause the water to be slightly discolored or have an odor.  

High Hazard

Locations such as hospitals, chemical plants, landscape companies are considered high (health) hazards because these non-potable systems are more likely to contain biological or chemical contaminants that could be introduced into the public potable water supply should a backflow event occur.  Biological and chemical contaminants can lead to serious injury or death.  


Backflow is the undesirable reversal of flow of a liquid, gas, or other substance in in a potable water distribution piping system as a result of a cross connection.  Water distribution systems are designed to flow in one 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 and pollutants can enter the potable drinking water system. A single backflow incident can potentially affect hundreds or even thousands of people.

There are two types of backflow:  backpressure and backsiphonage.  Backpressure occurs when the customer’s pressure exceeds the supply pressure, which can be created by booster pumps or temperature increases.  Backsiphonage occurs when the supply line pressure falls below atmospheric pressure (14.7 psi at sea level).  Supply line pressure drops are commonly caused by water line breaks, firefighting, and flushing. which can cause both types of backflow to occur.


There are many things you can do to help prevent a cross connection and or backflow event.

  • Do not submerge hoses or place hoses where they could become submerged.  A Air Gaphose connected to a faucet or spigot is a temporary extension of the potable water system.
  • Ensure an approved lead-free reduced pressure principle backflow assembly is installed, properly maintained, repaired, and tested annually on any property with lawn irrigation or fire systems.  
  • Install or replace hose bib vacuum breakers on hose spigots.
  • Ensure fixtures maintain an minimum of a 1-inch air gap (AG) or twice the inside diameter (ID) of the water supply flood rim level of the sink or tub.

Backflow Preventers

A backflow preventer is an assembly, device, or method that prohibits the backflow of water into potable water supply systems.  Devices do not have shutoff valves and are not testable in-line.  Assemblies possess 2 shut-off valves, 2 check valves, 4 test cocks and are testable in-line.  

The most common types of backflow preventers utilized in our system are the Hose-bibb Vaccum Breaker (HBVB), Residential Dual Check Valve (RDC), Double Check Valve (DC), and the Reduced Pressure Zone (RPZ).

The hose bibb vacuum breaker is a device that has been adapted to fit on a hose bibb or sill cock and operates on atmospheric pressure. 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.HBVB

The RDC is a device installed at the meter for single family residential homes.  Devices do not have shut-off valves and are not testable inline.


The DC is an assembly installed at locations that pose a non-health (moderate) hazard such as office buildings, some retail stores, and fire systems just to name a few.


Reduced pressure zone principle (RPZ) is an assembly that provides better protection for locations that pose a health (severe) hazard because it also contains a relief valve between the two check valves that opens or closes due to pressures that are applied to both sides. The RPZ is required at locations such as hospitals, schools, car washes, laundries, manufacturing and industrial plants, and where irrigation systems are in place. RPZ

The Town’s Cross Connection Control Administrator can assist you with determining the correct protection for the degree of hazard at your site.  

A list of approved backflow prevention assemblies can be found on the University of Southern California, Foundation for Cross Connection Control and Hydraulic Research at  Note when searching for an approved assembly please select Yes for the filter on the Pb (lead) column on the list.  All new or replaced backflow preventers must be approved lead-free assemblies.   Per the Cross Connection Control Ordinance backflow preventer installations are prohibited below grade or in pits. Grandfathered sites are required to bring their system up to current standard specifications for installation when:

  • The backflow preventer is unrepairable and needs replaced.  
  • A Commercial alteration or addition permit is acquired for improvements.
  • Change or use warrants increased backflow protection (i.e. non-health hazard, double check valve to a health hazard, reduced pressure zone assembly)