Building Permits Central: I Need a Backflow Preventer Inspection

Process Overview

Backflow preventers keep the public water supply safe from contamination from backflow or back-siphonage.

Metro Nashville requires that backflow preventers (with their meters) be installed for large residences and most commercial projects. Pools, irrigation, and sprinkler systems require backflow preventers. All backflow preventers must pass inspection for you to receive a Use and Occupancy (U and O) permit for your facility.

Where backflow preventers should be installed:

• Directly behind and as close to the water meter as possible
• Outside of the structure
• At or near the meter so no service branches are present upstream
• At least one foot above the 100-year floodplain
• In an area where the grade provides positive drainage, and the slope is not too steep

Need for Licensed Professional

The installation of a backflow preventer requires a licensed plumber who must work with you throughout the process.

Getting Started

1. Initiate a Building Permit Application

• Contact the Metro Nashville Codes Zoning Division in person by visiting the first floor of 800 2nd Avenue South, Nashville, TN 27320; by phone at 615-862-6510; or by email at [email protected].
• Zoning examiners will review plans and provide an application checklist that shows which departmental agency reviews are needed for your specific project.
• After receiving the permit application checklist, if “Cross Connect Review” is marked, you must make follow-up contact with another agency to meet the permit requirements. If the building is for a commercial project, email the Fire Department at [email protected] to start the process. If the project is residential, email Metro Water Services (MWS) at [email protected] to start the process.

2. Obtain the Permit

• Turn in your application to the Codes zoning examiners once the required signoffs and reviews are complete.
• If required, the permit allows a licensed plumber to install the backflow preventer.
• The Codes Department will issue the backflow preventer permit to the plumber.

3. Schedule an Inspection Date

• Backflow preventers must pass an initial inspection as well as an ongoing, annual inspection.
• The plumber/builder must initiate the backflow preventer inspection process by emailing [email protected].
• An inspection date will be scheduled at a time that works for both parties.
• If the scheduled date must be changed, email [email protected] to reschedule.
• Prior to the inspection, the plumber/builder will need to fill out a form with the backflow preventer specifics.

4. Installation

• The plumber/builder should install the backflow preventer and meter to be ready for the inspection date.
• The plumber should have the test ports in place at the time of the inspection.
• The plumber should make sure the backflow device and meter are accessible and meet all applicable regulations before and during the inspection.
• Schematics for all backflow inspector requirements can be accessed here. Go to the “Approved Construction Specifications and Details” section and select “Backflow Preventers” to download applicable information.

5. Inspection

• Water will be turned off at the time of the inspection. Depending on the facility, emergency authorities may need to be notified that the water will be shut off during inspection and that the system must be put into test mode.
• The inspection will ensure that the backflow preventer and meter are installed and working correctly.
• MWS will try to inspect the backflow preventer and its meter at the same time, but these are separate inspection processes and many need to be scheduled separately.

6. Inspection Results

• MWS inspectors determine and communicate the pass/fail results at the time of the inspection and provide supporting documentation. Your representative (plumber, building representative or maintenance person) receives a copy of the results from the inspector.
• If the inspection fails: The reason for failure is noted at the time of your inspection. You must call MWS to schedule a reinspection of the backflow preventer. The contact information to schedule this reinspection can be found on the information provided at the time of the inspection
• If the inspection passes, the backflow preventer will be set up for annual inspections.
• Problems can emerge at the time of the inspection. In many instances, a property owner wants to get a U and O permit and the final inspection is held up because the plumber is “long gone.” Make sure that your plumber is committed to assisting you throughout the process, up to and during all inspections required.

This description is intended to provide a general process overview and does not cover every situation. Each applicant’s situation depends on the particulars of the work to be done and the location of the property.