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Backflow Construction

Backflow prevention is important to keep Charlotte's water safe. Backflow prevention assemblies (BPAs) prevent dangerous substances from contaminating the drinking water system and must be tested once a year. On this page you can:

Learn how to comply with the application and installation processes for BPDs.

Application Process

Follow these steps to get your backflow prevention assembly connected, installed, and approved:

Obtain a metered connection with Charlotte Water by calling 980.338.1289 or 311 (locally) and ask for "New Services."
Complete and submit a Backflow Service Application.
Have your backflow plan reviewed if your project requires a new backflow preventer or the altering of an existing one.
Get a backflow prevention assembly inspection for each newly installed, relocated, or replaced backflow installation.

*Charlotte Water will apply fees for steps 3 and 4 on projects covered under Chapter 23: Article IV of the Charlotte City Code. The fees will be collected in the building permit fee collection process.

Backflow Installation Process and Requirements

With Irrigation Meter Connections

These are the required steps for installing an irrigation meter connection:

A licensed plumber must install the backflow prevention assembly.
Mecklenburg County Code Enforcement must inspect the installation. Call the Mecklenburg County Code Enforcement at 704.336.3829.
Charlotte Water must inspect the backflow prevention device assembly. Contact Charlotte Water (CLT Water) at 704-336-2456 for an inspection.

An initial passing test must be completed and submitted by an Approved Charlotte Water Backflow Tester within ten business days of the water meter being activated.

All Other Metered Connections

These are the requirements for all other metered connections, excluding single family or duplex residential homes:

All piping connected between the building and the Charlotte Water meter must be installed per any applicable NC Building Code and inspected by Mecklenburg County Code Enforcement Department according to its requirements.
A permit from Code Enforcement is required. Code Enforcement will inspect the work and release the permit holds it controls.
As part of the permitting and/or meter application process with Charlotte Water, a Backflow Service Application (BSA) will be required to be completed and returned with appropriate documents and/or fees.
This BSA becomes a Charlotte Water backflow permit request to install the backflow preventer. This work involves the backflow preventer and the piping five feet before and five feet after the backflow preventer.
Charlotte Water needs to inspect all work involved with installing the backflow preventer. Call Charlotte Water Backflow Inspections at 704-336-2456 to verify the status of a Backflow Hold or to schedule a backflow inspection.
Once the work has passed inspection, the Backflow Hold controlled by Charlotte Water will be released by the Installations and Development Services Section of the Engineering Division.
An initial passing test must be completed and submitted by an Approved Charlotte Water Backflow Tester within ten business days of the water meter being activated.
Submit an initial test of the backflow assembly in one of the following ways:

Backflow Inspection Checklist

Once your backflow prevention device has been installed, please review the following checklist of requirements before requesting an inspection from Mecklenburg County Code Enforcement or Charlotte Water.

Irrigation System Requirement

Mecklenburg County Code Enforcement will inspect all piping from the Charlotte Water installed meter up to and including the Reduced Pressure Principle (RP) backflow assembly.

An open ditch is needed for the inspection.
A meter will be required to pass inspection.
Coordinate activities to minimize conflicts with the open ditch.
Once Code Enforcement's inspection is completed, Charlotte Water Backflow will need to be contacted at 704.391.5188 to inspect the RP backflow assembly and activate the meter upon acceptance.

Piping Material

For ¾" to 1" Piping Material: Type K or Type L copper tubing, 1" min., or Sch. 40 PVC (conforming to ASTM D1785, pressure rated for water, using 1120 PVC compounds). When using Sch. 40 PVC pipe, Sch. 80 PVC fittings are required. When using PVC, vertical support at backflow assembly will be required and horizontal support is recommended. Proper priming (purple color) of PVC is required.
For 11/2" to 2" Piping Material: Type K or Type L copper tubing.
For 2 ½" to 12" Piping Material: Ductile iron pipe(minimum pressure Class 350), Type K or Type L copper tubing

Backflow Assembly

Correct type assembly installed as required by Charlotte Water.

Concrete Pad

All backflows 1½" and greater in size require a minimum of 4" thick concrete pad. All backflow smaller than 1½" requires a minimum of 4" thick washed stone.

Cover

Above-ground Installations need an insulated cover meeting ASSE 1060 requirements.
If it is an RP, the cover should provide drainage per Charlotte Water requirements.
Non-removable enclosures: If the structure is non-removable and must be entered in order to test or repair the assembly, the same minimum and maximum clearance that is specified for vault installations shall apply.

Vault

Below-ground Installations require a vault with a concrete or stone bottom.
All vaults must have drains according to Charlotte Water requirements.

Clearances/Locations

Make sure you meet all minimum required clearances.

For Reduced Pressure Principle Assemblies: Installed upright horizontal - aboveground outside zoning setback according to Charlotte Water standard details; minimum height from relief port to the ground is 12" and maximum is 30" inside a building or partially buried vault (special approval needed).

Size: Minimum Clearance

¾"-2", 30" from wall or any obstruction on the side utilized for testing and 6" from other side.
2½" -12", 30" from wall or any obstruction on the side utilized for testing and 12" from other side.
All: 4" from wall to shut off valve.
All: Floor drain or air-gap drain.

For Double Check Valve Assemblies:

Must be Installed upright and horizontal - above or below ground; outside zoning setback if above ground according to Charlotte Water standard details.
If below ground, device must be installed in vault with a concrete or stone bottom and provide for drainage to free atmosphere.
Minimum height from bottom of the assembly to the ground is 12" and the maximum is 30".

Vault

¾"-1": 8" from wall or any obstruction on the side utilized for testing and 4" from other side.
11/2"-2": 12" from wall or any obstruction on the side utilized for testing and 6" from other side.
4" clearance on each end.
2½"-12": 30" from wall or any obstruction on the side utilized for testing and 12" from other side.
8" clearance on each end.

Inside Building (special approval needed)

All: 4" from wall to shut off valve.
¾'-2": 30" from wall or any obstruction on the side utilized for testing and 6" from other side.
2½"-12": 30" from wall or any obstruction on the side utilized for testing and 12" from other side.

Contact Us

Charlotte Water Installation Development Services (IDS) oversees the application, sizing and construction of backflow prevention devices.

For all plan review, inspection, and permit fees, please send mail to the following address:

600 East Trade Street

Suite 20

Charlotte, NC 28202

For further questions, contact Mark Bullins (Environmental Compliance Manager - Backflow Prevention) at 704-432-5800.

Construction Resources

Need to request a backflow inspection after installation?

Call 704-336-2456 or email our backflow team. Charlotte Water Backflow Inspectors ensure your backflow prevention device was installed properly. After the inspection is completed, a backflow test performed by an approved tester is also required after approved. Schedule a test by finding a vendor near you on our List of Approved Testers(PDF, 136KB) - (updated periodically).