Land Development Services

CONTACT INFORMATION: Monday through Thursday, 8 a.m. - 4 p.m. and Friday, 9:15 a.m. - 4 p.m. Please note that visitors may not be added to in-person queues past 3:45 p.m.
703-222-0801 TTY 711
12055 Government Center Pkwy
Fairfax, VA 22035
Bill Hicks
Director

Department Resources

Cross Connection Control and Backflow Prevention Program

Backflow Prevention AssemblyA cross connection is a link between the water supply and a potential source of contamination. Backflow occurs when the water direction in a plumbing system flows backwards creating the potential for a contaminate to enter our public water system. Backflow prevention can be achieved through the use of backflow assemblies, devices or methods.

 

Backflow Prevention Assembly in cage protectionFairfax County’s Land Development Services and Fairfax Water work together to safeguard the water supply through implementation and monitoring of the Cross Connections Control and Backflow Prevention Program to identify hazards and ensure testing is conducted as required. Backflow prevention assemblies are required by the building code to be tested annually by a certified tester.

 

Cross Connection FAQs

FAQ - General

The notice indicates that Fairfax County has a record that one (1) or more Testable Backflow Prevention Assemblies are installed at your property. These assemblies may be installed on the water supply serving systems or equipment that have the potential to contaminate or pollute your drinking water. (I.E. Lawn Irrigation Systems, Fire Suppression Systems, EVAC Systems, In-Ground Pools, directly connected Hot Tubs, Steam Saunas, Steam Appliances, Cooling Towers, Heat Exchangers, Chillers, etc.)

These assemblies are required to be tested annually by a Virginia State Certified and Fairfax County Authorized Tester to ensure proper operation. Please follow the steps below.

Step 1 – Contract with a third party “Authorized Vendor” to conduct the required testing. A list of vendors is available at this link. Authorized Vendor List It is recommended you contact several from the list to obtain the best pricing.

Step 2 – The Vendor will conduct the test, complete all paperwork, and submit it to Fairfax County for approval and retention. If submitted properly by the vendor, and accepted by Fairfax County, you will be notified by email of the status of the submittal and receive a copy of the documents they submit. If accepted, this is your receipt that the work has been accepted for the given year or under the stated conditions.

Step 3 – If, an assembly “fails” testing, it must be repaired or replaced, and re-tested before a Backflow Assembly Test Report can be submitted by the vendor. If the assembly requires “replacement” that work requires a Plumbing Permit. Please reference the “Permitting and Inspections” portion of the FAQ.

Step 4 – You will receive an email from “noreply@workflownotification.com” when your Test Report is submitted by the Authorized Vendor and processed by Fairfax County. If you have not received confirmation by email for these events within 14 days of the test, please check your SPAM and JUNK folders or contact Fairfax County to confirm it has been submitted.

The Post Card or Newsletter you received regarding Backflow Prevention outlines a public safety concern and identifies necessary equipment designed to protect the Public Water Supply from Contamination and Pollution. Backflow Prevention Assemblies may be installed on the water supply serving equipment or systems that have the potential to contaminate or pollute your drinking water.

If your property has one (1) or more Testable Backflow Prevention Assembly installed, they are required to be tested for proper operation each year. Please follow the steps outlined in (Question 1 of this section). If you are unsure of what is installed but have one of the systems or equipment mentioned in (Question 1), please contact the Fairfax County Cross Connections Group to schedule a free site visit and evaluation.

A Cross Connection is any connection in a water distribution system that joins a potable water supply with a potential source of contamination or pollution, which may or may not have an impact on health.

Backflow Prevention Devices and Assemblies are One Way Plumbing Valves installed in a water distribution system to isolate Plumbing, Mechanical, and Fire Suppression Systems, and/or Fixtures, Appliance, and Equipment so they cannot cause contamination or pollution of the potable water system due to a “Backflow Event” or through migration.

A backflow event can occur due to “Back Siphoning” when the supply pressure of a water system is reduced. This may occur because of several scenarios (I.E. Distribution System Break or Maintenance, Fire Fighting through Fire Hydrants, Loss of Power to Pumping Equipment or Stations.

A backflow event can also occur due to “Back Pressure” when the supply pressure of a water system is less than the pressure being exerted by a downstream system or equipment. (I.E. when connected to equipment that heats water and causes expansion, or when water is pumped to a higher elevation for use.

A Backflow Prevention Device is a plumbing valve installed in line which is NOT testable or repairable and may be used for High or Low hazards depending on the specific application and the requirements of the code.

A Backflow Prevention Assembly is a plumbing valve installed in line which requires testing at installation, immediately following repair or relocation, AND at least annually. An Assembly is repairable in line. An assembly may be required for High or Low hazards depending on the specific application and the requirements of the code.

A “High Hazard” is any potential for “Contamination”, which impacts health or has the potential to make you sick. Some examples are Chemicals, Radiation, Pathogens, Bacteria, Viruses, Molds, and Pollen.

A “Low Hazard” is any potential for “Pollution”, which impacts the quality of water (I.E. Color, Taste, Odor), but does not impact health, or have the potential to make you sick. Some examples are Beverage Dispensing Machines, Coffee and Tea Brewers, some Water Treatment Equipment, and some Fire Suppression Systems.

You can access the Code Section referenced below at Codes and Standards.

Relevant Virginia Construction Code (VCC) Sections regulating Commercial Properties can be found in the current version of the Virginia Plumbing Code (VPC), See the following chapters.

  • Chapter 3 General Regulations
  • Chapter 4 Fixtures, Faucets, and Fixture Fittings
  • Chapter 6 Water Supply and Distribution

Relevant Virginia Construction Code (VCC) Sections regulating Residential Properties can be found in the current version of the Virginia Residential Code (VRC), See the chapters listed below. The Residential Code and Commercial Code are substantially equivalent in their requirements, however, if a requirement is not addressed in the Residential Code, the Commercial Code may be used as an alternative for regulation.

  • Chapter 25 Plumbing Administration
  • Chapter 26 General Plumbing Requirements
  • Chapter 27 Plumbing Fixture
  • Chapter 29 Water Supply and Distribution

Complete the “Authorized Vendor Application” located under “Vendor Resources” tab on the Cross Connections webpage.

Please send an email regarding your changes to LDS Cross Connection Program. Please DO NOT re-apply.

FAQ - Permitting and Inspection Requirements

Yes, you must obtain either a Commercial or Residential Plumbing Permit in all instances of installation, whether as new construction or replacement, and even when you are replacing “Like for Like”. A Plumbing Permit is also required for the installation of a Testable Backflow Prevention Assembly on Water Based Fire Suppression Systems designed under NFPA 13, 13R, and 13D (Stand Alone).

No, Other endorsements are allowed to submit application and obtain a Plumbing Permit for the installation of a Testable Backflow Prevention Assembly in Fairfax County. This may not be allowed in other jurisdictions. Additional endorsements include:

  • Fire Sprinkler (SPR)
  • Landscape Irrigation (ISC)
  • Water Well/Pump (WWP)

When completing your permit application, you should include a statement in the “Work Description” field which states “Installation of Testable Backflow Assembly(s) for the (system or equipment you are protecting against backflow)”.

For endorsements other than Plumbing Contractors you MUST select “Backflow Preventer Only” under “Work Type” and select “Backflow Preventer-Testable Assembly” under “Equipment Details” for each assembly you are installing. If you are installing Backflow Prevention Devices also, you must select “Backflow Preventer – Non-Testable Device for each device you are installing as well.

Backflow Preventers will be inspected at Plumbing Final. If the installation is simple, having only one (1) or two (2) Backflow Preventers, installed without the need for Plumbing Plans or related to a Building, Alteration, or Separation Permit, this inspection may be completed virtually, at the discretion of the inspector. Please follow the steps below:

Step 1: Ensure all Backflow Prevention Devices and Assemblies are identified on the ‘Equipment Details” of a Plumbing Permit.

Step 2: Ensure all Backflow Prevention Devices and Assemblies identified on the Plumbing Permit are installed and supplied with water.

Step 3: Contract with an Authorized Vendor to conduct Backflow Prevention Assembly Testing for all Testable Backflow Prevention Assemblies identified on the Plumbing Permit.

Step 4: Ensure the Authorized Vendor submits the Test Report to Fairfax County Cross Connections. The submittal MUST include the associated Plumbing Permit Number.

Step 5: The Cross Connections Group will process the Test Report submitted, and if correct and accepted, enter a “Cross Connections Inspection” into the Plumbing Permit indicated, stating that the testing has been received for XX Backflow Assemblies, Having XX Serial Numbers, Serving XX Equipment/System. The Plumbing Inspector will confirm this inspection entry prior to approving a Final Inspection.

Step 6: Schedule your Final Plumbing Inspection.

In some cases, if the installation is simple, having only one (1) or two (2) Backflow Preventers, which are installed without the need for Plumbing Plans or related to a Building, Alteration, or Separation Permit or when installed as a Replacement, the Final Plumbing inspection may be conducted virtually. This may include the requirement to submit photos of the installation. Conducting an inspection virtually will be at the sole discretion of the Inspector.

** It is recommended you contact the Inspector prior to scheduling your Final Inspection to discuss this option.

The Annual or Post Occupancy testing of a Backflow Prevention Assembly doesn’t require a permit. However, Testing conducted after the initial test completed at install must be submitted under the appropriate Cross Connections Record ID Number (permit number). All testing of Backflow Prevention Assemblies MUST be completed by an Authorized Vendor of Fairfax County, who also holds a Tradesman Certification such as “Backflow Prevention Device Worker” by the State of Virginia.

Virginia State Law requires all individuals conducting Backflow Prevention Assembly Testing obtain a certification through the Department of Professional and Occupational Regulation (DPOR) as a “Backflow Prevention Device Worker”. You must use a company or individual from the Fairfax County Authorized Vendor List to conduct all pre and post occupancy Backflow Prevention Assembly testing.

All Authorized Vendors on the Fairfax County List MUST agree to the following criteria to become or remain authorized to test backflow assemblies in Fairfax County:

  • Conduct the testing of all Backflow Prevention Assemblies at your property
  • Complete the necessary paperwork.
  • Submit all required documents to Fairfax County in a timely manner.

These tasks cannot be delegated to the Property Owner or Owner Agent. If, the vendor you hire refuses or attempts to delegate this work, please contact LDS Cross Connection Program.

The permanent removal of a Backflow Preventer requires the System, Equipment, or Appliance the backflow preventer is protecting against also be removed, if feasible, or abandoned in place and permanently disconnected from the distribution system. This removal or disconnection doesn’t require a Permit; however, it MUST be verified by a Fairfax County Cross Connections Inspector. Please follow the steps below.

Step 1: Request an “Abandonment / Removal” Inspection by sending an email to the LDS Cross Connection Program. Please ensure you include the Property Address, Business Name, and Record ID Number in your email.

Step 2: The Cross Connections inspector for your Inspection Area will contact you to discuss the removal. They will give you specific instruction on what conditions and criteria must be met to complete the removal.

Step 3: Complete the removal as instructed by the inspector and contact the inspector to inform them you are ready for an Inspection.

Step 4: The Inspector will contact you to schedule the inspection and update the Cross Connections Record as needed. For simple removals, if before and after photos are provided, the inspector, at their discretion, may choose to conduct the inspection virtually.

Fairfax County will NOT accept partial or incomplete Backflow Assembly Test Reports. All Backflow Prevention Assemblies installed at the location are required to be tested, and passed, when due each year. If a Backflow Assembly “Fails” testing, it must be repaired or replaced and re-tested as passing prior to the Test Report being submitted or accepted. If a Backflow Prevention Assembly is installed, it MUST be tested, whether it is “In Use” or not. If a Backflow Assembly is in any other condition mentioned above it must be verified by a Cross Connections Inspector. (Please follow the instructions under Question 8).

FAQ - Lawn Irrigation Systems

The Post Card or Newsletter you received regarding Backflow Prevention outlines a public safety concern and identifies necessary equipment designed to protect the Public Water Supply and your Drinking Water from contamination and pollution. A Testable Backflow Prevention Assembly should be installed, and tested annually, to isolate the Lawn Irrigation System from the Drinking Water supplied to the home. These assemblies may be installed on the water supply serving equipment or systems that have the potential to contaminate or pollute your drinking water (i.e. Lawn Irrigation Systems, Fire Suppression Systems, In-Ground Pools, directly connected Hot Tubs, Steam Saunas, etc.). These assemblies are required to be tested annually, by a Virginia State Certified Tester, to ensure proper operation. Please follow the steps below.

Step 1 – Contract with a third party “Authorized Vendor” to conduct the testing. A list of vendors is available at this link. Authorized Vendor List. It is recommended you contact several on the list to obtain the best pricing.

Step 2 – The Vendor will conduct the test, complete all paperwork, and submit it to Fairfax County for approval and retention. If submitted properly by the vendor, and accepted by Fairfax County, you will be notified by email of the status of the submittal and receive a copy of the documents they submit. If accepted, this is your receipt that the work has been accepted for the given year or under the stated conditions.

Step 3 – If, an assembly “fails” testing, it must be repaired or replaced, and re-tested before a Backflow Assembly Test Report can be submitted by the vendor.

Step 4 – If, you have not received confirmation your backflow testing has been submitted or accepted within 14 days of the test, please contact Fairfax County to confirm at LDS Cross Connection Program.

The requirements to have a “High Hazard” Testable Backflow Prevention Assembly protecting In-ground Lawn Irrigation Systems, and to have that assembly tested for proper operation each year, have been in the Virginia Uniform Statewide Building Code (VUSBC) since the early 70’s. These requirements have also been similarly stated in the Virginia Department of Health Waterworks Regulations (VDH) since 1993. Though the specific language has been modified and updated over the years, the intent has remained substantially equivalent. These are not “new” requirements or unique to Fairfax County. They are requirements of the State of Virginia and have been for over 50 years.

The primary concern for Lawn Irrigation Systems is that the spray heads are not sealed and are continuously in direct contact with the soil. This exposes the water in the system to any contaminate which is present in your yard.  Backflow Assemblies are designed to prevent contamination which may occur during backflow events when your system is active or through migration when your system is idle. Some likely contaminates to consider are:

  • Chemicals in Fertilizers, Weed Killers, and Pesticides
  • Bacteria such as E.coli, Coliform, Salmonellosis, and Tetanus
  • Parasites and Viruses contained in Animal Excrement or Insect Larvae such as Roundworm and West Nile.
  • Spores such as Molds and Pollen

There is no way to predict when or what type of contamination will occur, or what level of concentration, or duration of exposure may be harmful to an individual. Which is why the VUSBC and VDH regulations require a “High Hazard” Backflow Prevention Device or Assembly for protection, on ALL In-ground Lawn Irrigation Systems.

Unfortunately, many if not most, Lawn Irrigation Systems have been installed over the years, after occupancy and without proper permits. This means the system was likely never final inspected and many are not equipped with the proper level of backflow protection required by the VUSBC or VDH.

We cannot agree, by accepting, that a system is properly safeguarded if it is not. We encourage all our customers to install a proper Testable Backflow Prevention Assembly as soon as is feasible to protect your health and the health of others. You can find a list of “Authorized Vendors”, licensed and certified to complete this work on the Authorized Vendor List.

  • Virginia Residential Code (2021), effective January 1st, 2025

    P2902.5.3 Lawn irrigation systems.

    The potable water supply to lawn irrigation systems shall be protected against backflow by an atmospheric vacuum breaker, a pressure vacuum-breaker assembly or a reduced pressure principle backflow prevention assembly. Valves shall not be installed downstream from an atmospheric vacuum breaker. Where chemicals are introduced into the system, the potable water supply shall be protected against backflow by a reduced pressure principle backflow prevention assembly.

    P2503.8.2 Testing.

    Reduced pressure principle, double check, double check detector and pressure vacuum breaker backflow preventer assemblies shall be tested at the time of installation, immediately after repairs or relocation and every year thereafter.
     
  • Virginia Department of Health Waterworks Regulations, effective June 23rd, 2021 (the word “Owner” below is referring to the owner of the distribution system, the Water Authority (Fairfax or Vienna Water), not the property owner.

    12VAC5-590-580. General requirements for cross-connection control and backflow prevention.

    (B) No owner shall install, maintain, or allow a service connection to any premises where cross-connections to a waterworks or a consumer's water system exist, unless the owner and department ensure the cross-connections are adequately safeguarded.

    12VAC5-590-600. Cross-connection control program responsibilities.

    (C) The CCCP shall ensure complete assessments of every consumer's water system and shall determine both the degree of hazard and the appropriateness of existing safeguards to prevent contamination from cross-connections and backflow.

    (D) The CCCP shall ensure testing, maintenance, and repairs of all backflow prevention assemblies, backflow elimination methods, and backflow prevention devices required and installed pursuant to 12VAC5-590-610.

    (E) 13VAC5-63-530, which incorporates the International Property Maintenance Code into the USBC, requires testing of RPZ assemblies, double check valve assemblies, double check detector backflow assemblies, and pressure vacuum breaker assemblies after initial installation, immediately after repairs or relocation, and annually thereafter…

    12VAC5-590-610. Containment of backflow.

    (A) The owner shall ensure installation of backflow prevention assemblies or backflow elimination methods (i) at the service connection or (ii) downstream of the service connection but before any unprotected takeoffs.

    12VAC5-590-630. Backflow prevention assemblies, devices, and backflow elimination methods for containment.

    (A) Any backflow prevention assembly or backflow elimination method or backflow prevention device shall be of the approved type and shall comply with the USBC.

Typically, residential customers will have either an Atmospheric Vacuum Breaker Backflow Prevention Device (AVB), Pressure Vacuum Breaker Backflow Prevention Assembly (PVB) or a Reduced Pressure Principle Backflow Prevention Assembly (RP) Installed on their Residential Lawn Irrigation System. However, each Device or Assembly has unique installation criteria and design limitations. It is important that the correct backflow preventer is installed for your design.

AVB
AVB
PVB
PVB
RP
RP
 

This Device or Assembly is typically located in a mechanical space, or immediately outside, where the supply for the Lawn Irrigations System exits the home. It may also be in your front yard close to the Meter Crock for your Water Service. If you cannot locate one of the backflow preventers (shown above) on your property, when it’s time to turn on your irrigation system for the season, ask the company you hire to locate your backflow preventer for you and show you where it is. Or contact the Fairfax County Cross Connections Program to request a free site visit and evaluation.

When it’s time to turn on your Lawn Irrigation System for the season, ask the company you hire if they are “Authorized” to test Backflow Prevention Assemblies in Fairfax County. If they are not Registered as a Fairfax County Authorized Vendor, please hire a certified tester from the Authorized Vendor List located on the Fairfax County Cross Connections Website under the “Customer Resources” tab to conduct the Backflow Testing. Please follow the steps outlined in (Question 1).

The most common Backflow Prevention Device we see installed in error, is a Dual Check Valve Backflow Prevention Device (pictured below). While this device provides some protection from backflow, it is not designed to prevent potential hazardous contamination of your drinking water during a backflow event or through migration. We encourage all our customers to install a Testable Backflow Prevention Assembly in accordance with VUSBC and VDH requirements as soon as is feasible. To find an authorized vendor, please visit the Authorized Vendor List.

Dual Check Valve Backflow Prevention Device
Dual Check Valve Backflow Prevention Device

Yes, in all instances of installation, whether as new construction or replacement, and even when you are replacing “Like for Like”. See the “Permitting and Inspections” section in this FAQ for further guidance.

FAQ - Fire Suppression Systems

All Water Based Fire Suppressions Systems require a Fire Sprinkler Permit issued by the Office of the Fire Marshal. In addition, a Plumbing Permit issued by Land Development Services is required for all Water Based Fire Suppression Systems designed under NFPA 13, 13R and 13D (Stand Alone).

The Plumbing Permit must identify, under the “Equipment Details”, all Testable Backflow Prevention Assemblies required for these systems. The Plumbing Permit for these backflow preventers must receive a “Final Inspection” prior to occupancy.

NFPA 13D offers several design options. It offers the option for a “Stand Alone” design, and options for “Multipurpose” Designs. A multipurpose design shall not require backflow prevention if it complies with all criteria identified in VRC Section P2904.

Stand Alone designs, which are interconnected with the private water distribution system, DO NOT meet the requirements of VRC Section P2904, and therefore, must meet the requirements of VRC Section P2902. Please refer to the Technical Bulletin issued by LDS in April of 2024 regarding this interpretation.

Yes, In Fairfax County, Plumbing Permits can be issued to contractors in addition to those having Plumbing Endorsements for their Contractors License. Please reference Question 2 of the “Permits and Inspections” Section.

Resources

Download Test Report

Locate and download your pre-filled Backflow Assembly Test Report.

Submit Test Reports

Please review the requirements and responsibilities prior to submitting your test report.

Update Contact

It is your responsibility to inform the county of a change in ownership or responsible party.

Register Your Residential Lawn Irrigation or Fire Suppression System

If your property has a lawn irrigation system or water-based fire suppression system, please ensure it is registered with Fairfax County.

Requirements and Responsibilities

There are minimum requirements for the installation and testing of backflow preventers.  Find out more about this and your responsibilities as an owner and contractor.

Minimum Requirements for Installation and Testing

Contact Us

For questions regarding the Cross Connections and Backflow Prevention Program, please contact Land Development Services, Building Division, at 703-222-0801, TTY 711, or by email.


 

 


Need Help? Call 703-222-0801, TTY 711.

Monday through Thursday from 8 a.m. to 4 p.m. and Friday from 9:15 a.m. to 4 p.m.

 

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