Air Gap
Shall be installed assuring the vertical distance between the supply pipe and the overflow rim of the receiving tank must be at least twice the diameter of the supply pipe. (Picture of Air Gap)
Vacuum Breakers
Shall be installed as per the manufacturer's recommendations.
Double Check Valve Assembly 2" and Smaller
Must be placed prior to any branch or connection to the distribution system. The device may be installed utilizing the following options: (Picture of DCVA 2" or Smaller)
- Inside Installation: Shall be installed with adequate space to facilitate maintenance and testing. A minimum space of 12" shall be allowed on all sides for maintenance, testing and repair. The assembly shall be protected from freezing temperatures. Assembly shall be installed as per manufacturer's recommendations.
- In-Ground Installation: Shall be installed in an adequately sized box to allow for proper testing. The device shall have a minimum clearance of 6" on all sides. There must be a minimum of 6" of clean gravel placed in the bottom of the box. Assembly shall be placed in a traffic grade box within any area subject to vehicular traffic. Assembly shall be installed per manufacturer's recommendations.
Double Check Valve Assembly Larger than 2"
Must be placed prior to any branch or connection to the distribution system. The device may be installed utilizing the following options: (Picture of DCVA Larger than 2")
- Inside Installation: Shall be installed with adequate space to facilitate maintenance and testing. A minimum space of 12" shall be allowed on all sides for maintenance, testing and repair. The valve shall be protected from freezing temperatures. Assembly shall be installed as per manufacturer's recommendations.
- In-Ground Installation: Shall be installed in an adequately sized vault to allow for property testing of the device. The vault shall be equipped with a minimum of a 24" by 24" top opening hatch. Walls may be precast concrete, reinforced poured in place concrete or filled block. The vault shall be sized to meet the minimum clearances as shown in JMWSC Backflow Prevention Manual. There must be a minimum of 12" of clean gravel placed in the bottom of the box. Vault is to be constructed as to prevent the retention of water. Assembly shall be placed in a traffic grade box when located within any area subject to vehicular traffic.
- Above-Ground Installation: Shall be installed in an adequately sized enclosure to allow for proper testing of device. The sides of the vault shall be made of concrete filled block and shall be equipped with a removable top. The top shall be securely fastened to the vault. The vault shall be sized to meet the minimum clearances as shown in JMWSC Backflow Prevention Manual. The backflow assembly shall be adequately protected from freezing.
Reduced Pressure Principle Assembly
Must be placed prior to any branch or connection to the distribution system. The device may be installed utilizing the following options: (Picture of RPPA)
- Inside Installation: Shall be installed with adequate space to facilitate maintenance and testing. A minimum space of 12" plus the nominal size of the device shall be allowed on all sides from maintenance, testing and repair. The valve shall be protected from freezing temperatures. Assembly shall be installed as per manufacturer's recommendations.
- Above-Ground Installation: Shall be installed in an adequately sized enclosure to allow for proper testing of the device. The sides of the vault shall be made of concrete filled block and shall be equipped with a removable top. The top shall be securely fastened to the vault. The vault shall be sized to meet the minimum clearances as shown in JMWSC Backflow Prevention Manual.
New Commercial Assemblies
All newly installed commercial assemblies shall be tested by a certified tester immediately after installation and once each subsequent year. All costs associated with the testing of the assembly shall be the responsibility of the owner. If test results of this device are not provided to the Commission within the allotted time as prescribed in a written letter from the Commission, then the device will be tested by the Commission or a representative thereof and all costs associated with the testing of this device will be charged to the owner's account.
Existing Commercial Assemblies
As per SCDHEC requirements, all backflow prevention assemblies must be tested annually by a certified tester. All costs associated with the testing of the assembly shall be the responsibility of the owner. Copies of these test results are to be furnished to the Commission. The assembly shall be installed as per manufacturer's recommendations.
Notification of Testing
The Commission will notify all commercial owners of backflow prevention assemblies thirty (30) days prior to the due date of the test report. If this report is not received by the given due date, a second letter will be sent to the owner allowing for fifteen more days. If test results are not received by the second due date, the existing device will be tested by the Commission, or a representative thereof, and all costs associated with the testing of this device will be charged to the owner's account as per the Commission's Backflow Testing Rate Schedule.
Annual Testing Agreement
If you would like the Commission to complete the required annual testing of the backflow prevention device(s) installed at your location, please complete the Annual Testing Agreement. Upon receipt of the completed document, the Commission will test the backflow prevention device(s) until such time as the agreement is terminated in writing by the owner. All costs associated with the testing of the device(s) will be charged to the owner's account per the Commission's Commercial Backflow Testing Rate Schedule.
Certified Tester
A current list of certified testers for South Carolina can be found at SCDHEC Testers.
Commercial: When a commercial/industrial backflow prevention device is found to be malfunctioning, the device must be repaired immediately. The results of the repaired device must be provided to the Commission within fifteen days of the date that the malfunctioning device was discovered. Failure to repair this device may result in a termination of water service.
At no time shall a backflow prevention device be removed or straight piped. Doing so will result in an immediate termination of water service by the Commission.
The Commission will constantly review existing services to determine if they are meeting compliance requirements of the Commission's Cross Connection Control Program.
No Existing Device
If the Commission determines that a service is a potential hazard and there is no form of backflow prevention, then the owner/customer will be notified immediately his /her non compliance. The owner will be given 30 days to install the required device and provide the test reports of this device to the Commission. If the owner/customer is still in non compliance after thirty days, a certified letter will be sent to the owner/customer allowing fifteen (15) additional days to meet compliance. Costs will be applied to the owners account for the issuance this second notice. If the owner remains in non-compliance, water service will be terminated until requirements are met.
Improper Device
If the Commission determines that a facility has an improper device, then the owner/customer will be notified immediately of his/her non-compliance. The owner will be given thirty (30) days to install the appropriate device and provide the test reports of this device to the Commission. If the owner/customer is still in non-compliance after thirty days, a certified letter will be sent to the owner/customer allowing fifteen (15) additional days to meet compliance. Costs will be applied to the owners account for the issuance of this second notice. If the owner remains in non-compliance, water service will be terminated until requirements are met.
Improper Installation of Device
If the Commission determines that a facility has an improper installation of a device, then the owner/customer will be notified immediately of his/her non-compliance. The owner will be given thirty (30) days to correct the device and provide the test reports of this device to the Commission. If the owner/customer is still in non-compliance after thirty days, a certified letter will be sent to the owner/customer allowing fifteen (15) additional days to meet compliance. Costs will be applied to the owners account for the issuance of this second notice. If the owner remains in non-compliance, water service will be terminated until requirements are met.