Water Distribution

Water Distribution System / Backflow Requirements

Drinking water is delivered to homes and businesses through the water distribution system, a network of infrastructure that includes pipes, valves, fire hydrants, pump stations, and storage tanks. Orangeburg DPU has more than 600 miles of water mains, all of which must be maintained to ensure the water keeps flowing 24 hours a day, 365 days a year.

Pumps at our John F Pearson Water Treatment Plant pump water into the distribution system. Pressures leaving the plant range from 70 to 80 pounds per square inch (psi), depending on the number and type of pumps in operation. We also have  3 pumping stations and 9 storage tanks throughout the distribution system to maintain pressure and meet peak water demands.

Fire Hydrants
Fire hydrants are owned and maintained by Orangeburg DPU and our water distribution system currently has more than 1,600 fire hydrants in service.

We do allow fire hydrants to be used for temporary water service, but this requires a fire hydrant meter to be installed. For more information, please contact our Water Division at 803-268-4404.

Water Main Flushing
Over time, minerals and other deposits can accumulate inside water mains. To clean the mains and remove these deposits, DPU Water Division personnel periodically use a technique called Unidirectional Flushing, or UDF.

Flushing water mains involves opening a nearby fire hydrant and discharging water from the hydrant; the high velocity of the water cleans the inside of the mains.

Backflow Requirements:

Safeguarding our public water system is an essential part of our mission to protect public health. 

Each connection on our system, residential homes and commercial businesses, present an opportunity for contaminated water to enter our water system.  Without the use of backflow preventers, water from private systems, such as industrial plants, and medical facilities, could enter our system, and impact the water quality.

To protect our system, DPU has a backflow prevention program that is strictly monitored and enforced. 

What is backflow?

Backflow (BF) is the reversed flow of non-potable water or other substances into the public water system.  It is caused by a drop in pressure in the public water system.

Who is required to have a Backflow Preventing Device?

Since backflow hazards are determined by the type of business, and how water is used, we evaluate each account on an individual basis.  The types of accounts that require a backflow preventer are:

  1. Restaurants
  2. Dry Cleaners
  3. Medical Offices
  4. Funeral Homes
  5. Beauty and Nail Salons
  6. Car Washes
  7. Multi-tenant Retail Space
  8. Commercial Buildings 3 stories or taller
  9. Commercial Space with a Dedicated Fire Service Line/Sprinkler System
  10. Churches with Baptismal Pools
  11. Irrigation systems
DPU Responsibilities
  1. Preventing water from unapproved sources, or any other substance, from entering the Water Distribution System.
  2. Maintaining a viable cross-connection program by State and Federal Regulations.
  3. Locating and eliminating unprotected cross-connections.
  4. Maintaining records of existing backflow preventer locations and annual test results.
  5. Advising the customer of two methods of protection, Isolation and Containment.
  6. Determining when a backflow device is needed.
  7. Notifying customers by mail of upcoming tests
Plumbing Inspector Responsibilities
    1. Inquire about the intended use of water.
    2. Recognize where a potential cross-connection might be made.
    3. Recognize where a potential cross-connection is called for by the plans.
    4. Consult with the customer and the department about these findings.
Customer Responsibilities
  1. Preventing pollutants and contaminants from entering his/her potable water system or the public water system.
  2. The customer will be required, by the Department of Public Utilities, to perfom  the following for their backflow prevention devices.
    1. Install
    2. Operate
    3. Annually Test
    4. Maintain
  3. Maintain accurate records of tests and repairs made to BF devices.
  4. Testing of devices after any repair, overhaul, re-piping or relocation insuring it to be in good operation condition and will prevent backflow.
  5. Have certified tester repair BF devices.
  6. Notify DPU’s BF Representative of the date and time of the test and/or repairs.

Tester Responsibility


  1. Perform accurate field test
  2. Repair or Overhaul BF devices
  3. Report repairs and overhauling to customer and DPU.
  4. Must be equipped with and capable of using the necessary tools, gages, and other equipment to properly test, repair and maintain BF devices
  5. The tester may not change the design, material or operational characteristics of an assembly during repair or maintenance without prior approval of the Department of Public Utilities.
  6. The tester shall perform the work and will be responsible for the accuracy of the reports.
  7. Completely fill out the test report form. (New Device, Replacement, Removal etc.…) (Link to Test Form)
  8. Report any issues around the devices to DPU.
  9. Notify the customer and DPU of potential cross-connections.
  10. The ability to communicate with DPU if questions or problems arise.
  11. Notify DPU’s Cross Connection Control Representative of the date and time of the test and/or repairs.
  12. DPU performs inspections periodically.  When an inspection is done and the department sees that something is not reported, your testing privileges on the DPU water system may be revoked.

Backflow Device Selection


      1. Devices are required on meters 1.5” and larger unless potential for cross-connection is a high hazard facility.
      2. BF assembly selection and installation must meet requirements set by:
        1. University of Southern California Foundation for Cross Connection Control and Hydraulic Research
        2. South Carolina Department of Health and Environmental Control
        3. Current South Carolina Building Code
        4. Department of Public Utilities Code of Practice
      3. BF assemblies must be selected from the South Carolina Department of Health and Environmental Control’s list of approved devices. (http://www.scdhec.gov/Environment/docs/dwbf_assembly.doc)
      4. Backflow assemblies permitted for containment protection are as follows:
        1. Double Check Valve Assembly (DCVA) Low Hazard
        2. Reduced Pressure Principle Assembly (RP) High Hazard
        3. Pressure Vacuum Breaker (PVB)
      1. BF assemblies two (2”) inches and smaller must be equipped with ball valves, one on each side of the assembly.
      2. BF assemblies larger than two (2”) inches must be equipped with resilient seat gate valves, one on each side of the assembly.
      3. DPU will require and endorse the installation of BF devices at meter for Containment protection and favors isolation method for protection within the work area.
      4. It is recommended that adequate space is left inside the building or near the meter should system modifications require BF protection.
      5. BF assemblies shall be installed on the customers’ side of the water meter prior to any tap, tee, or service connection.
      6. BF assemblies must be readily available for in line maintenance and testing
        1. BF assemblies must be installed per manufacturer’s and DPU’s specs.  Details of proper installation are available upon request from DPU by calling 803-268-4404

Backflow Device Installation Requirements
      1. The certified tester shall send the completed test report form with the following:
        1. Exact location of each device
        2. Make
        3. Model
        4. Size
        5. Type BF device
        6. Serial Number
        7. Installation Date
        8. Signature
        9. Certification Number
        10. All Contact Information for tester and facility
      2. The following steps must be taken after the installation of a new tap and newly installed device:
        1. The meter will be turned off after installation of a new tap
        2. Someone must notify the Cross-Connection Control Representative and schedule the meter to be turned on for testing and inspection of the newly installed assembly 2 days in advance of the testing.  Testing and inspection of assembly can be done at the same time.
        3. If the device fails the meter will be turned back off, repairs will be made and steps 1-2 will be repeated.
        4. After testing is completed and the assembly has passed inspection the meter will be left on.  Test reports must be turned in to the Department within 1 business day.  Meter will be turned off if reports are not turned in to the department.
    1. Backflow Device Replacement or Restoration Requirements

When replacing or restoring an existing assembly to service, the following procedures apply:

      1. Replacing
        1. Reassessment – Prior to replacing an existing backflow assembly, contact the Department Cross-Connection Control Representative to request a reassessment of system protection requirements.  The purpose of reassessment is to ensure system protection is in accordance with the most current Program requirements.
        2. Inspection – When an existing backflow assembly is replaced, the new assembly must be inspected by an approved certified tester to verify it is in accordance with Program requirements.  A request for inspection must be received within 2 days of installation.
        3. Testing – When an existing backflow assembly is replaced, the new assembly must be tested by an approved certified tester.  Testing must be performed within 10 days upon successful completion of inspection by an approved certified tester

        ii. Restoring Service
        1. When an existing backflow assembly is restored to service after previously being disconnected or removed from service, the assembly must be tested by an approved certified tester. Testing must be performed within 10 days upon restoring the assembly to service.
        2. Documents and Forms
          1. SCDHEC Certified Tester List
          2. Backflow Test Form