Backflow Laws: North Carolina
North Carolina Backflow Prevention Laws, Regulations, and Compliance Requirements
North Carolina's backflow prevention requirements are established in the Rules Governing Public Water Systems (15A NCAC 18C .0406 and Appendix B), administered by NCDEQ Division of Water Resources. A significant statewide change occurred with NC Senate Bill 166 in September 2024, which reduced residential irrigation backflow testing from every 2 years to every 3 years. Commercial backflow assemblies continue to require annual testing. North Carolina utilities certify testers locally — Raleigh, Charlotte, Durham, and other utilities each maintain their own certification schools. This guide covers the full NC regulatory framework and major utility programs.
North Carolina State Regulatory Framework
North Carolina’s cross-connection control requirements are established in the Rules Governing Public Water Systems at 15A NCAC 18C .0406 (Section 18C, Cross-Connection Control and Backflow Prevention) and its Appendix B, administered by NCDEQ Division of Water Resources. North Carolina holds EPA primacy under the federal Safe Drinking Water Act.
The NC rules require public water systems to install or require installation of appropriate testable backflow prevention assemblies prior to providing service to premises with identified cross-connection hazards. Backflow prevention assemblies must be on the USC-FCCCHR approved list and must meet ASSE standards. Assembly requirements depend on the degree of hazard assessed under Appendix B of the Rules Governing Public Water Systems.
NC Senate Bill 166 — September 2024 Residential Irrigation Change
North Carolina Senate Bill 166, signed September 2024, significantly changed the testing frequency for residential irrigation backflow assemblies that do not apply or dispose chemical feeds. Effective for certifications submitted on or after September 1, 2024: qualifying residential irrigation customers are placed on a three-year testing cycle rather than the previous two-year cycle. Commercial backflow assemblies — and residential irrigation systems that do use chemical feeds — continue to require annual testing. Multiple North Carolina utilities (Apex, Winston-Salem/Forsyth County, Union County, Raleigh) have issued updated compliance communications to customers explaining this change.
North Carolina's Locally-Administered Tester Certification
North Carolina does not administer a statewide backflow tester certification — instead, certification is handled locally by each water utility through their own certification schools. Major North Carolina utilities with established certification schools include: City of Raleigh (certifications accepted from Raleigh’s own school and a list of approved schools), Charlotte-Mecklenburg Utilities, City of Durham Department of Water Management, Greenville Utilities Commission, and North Carolina Rural Water Association (NCRWA).
Raleigh accepts certifications from its own school plus: Durham, Charlotte-Mecklenburg Utilities, Central Piedmont Community College, Greenville Utilities, and NCRWA. All testers must also maintain annual calibration of their differential or electronic test kit. Testers working across multiple North Carolina utilities must confirm their certification is accepted by each specific utility before submitting test reports there.
North Carolina's Utility-Specific Certification Schools
Because NC tester certification is locally administered, a tester certified by Raleigh may or may not be accepted by Charlotte, Winston-Salem, or Greenville. Each utility publishes a list of approved certification schools and requires registration with that utility before test reports can be submitted. Property managers working across multiple NC utilities should confirm accepted credentials with each utility — and contractors should register separately with each utility service area where they plan to work.
Major Water Purveyors in North Carolina
City of Raleigh Water (Raleigh Water)
Raleigh Water serves approximately 500,000 customers in Wake County and surrounding areas, making it North Carolina’s largest municipal water system. Raleigh’s cross-connection control program operates under Raleigh City Code Article D (Water Quality Protection) and Appendix A (Guidelines and Requirements for the Cross Connection Program), aligned with 15A NCAC 18C rules.
Raleigh’s testing schedule: commercial irrigation assemblies must be tested annually by July 1st. Residential irrigation assemblies must have a passing test every 3 years (per NC SB 166, the due date is July 31st of the assigned year). All other commercial backflow assemblies are tested annually by zip code (different zip codes have staggered annual deadlines throughout the year). Failed assemblies must be repaired, rebuilt, or replaced and retested within 15 days for health hazard facilities and 30 days for non-health hazard facilities. Raleigh uses VEPO as its test result submission system. Testers must be certified by one of Raleigh’s approved schools and registered with Raleigh’s Cross Connection Control Program before submitting reports.
Charlotte-Mecklenburg Utilities (CMUWS)
Charlotte-Mecklenburg Utilities serves approximately 1 million people in Mecklenburg County and surrounding areas. CMUWS operates one of North Carolina’s largest and most active cross-connection control programs. Annual testing is required for commercial assemblies. CMUWS maintains its own certification school (5100 Brookshire Blvd, 704-399-2426 ext. 295) and accepts testers from other approved NC schools.
City of Durham Department of Water Management
Durham’s water management department serves Durham County and surrounding areas. Durham operates its own Backflow Prevention Program with a certification school (101 City Hall Plaza, 919-560-4194 ext. 35249). Durham’s program requires annual testing for commercial assemblies. Durham-certified testers are accepted by Raleigh and other NC utilities that have reciprocal agreements with Durham’s school.
Winston-Salem / Forsyth County Utilities (WSFC Utilities)
WSFC Utilities serves the Winston-Salem metro area. WSFC has contracted with BSI Online to administer its backflow test reporting program. BSI Online sends notification letters to customers 30 days before testing due dates and manages the compliance tracking database. Testers wishing to submit results for WSFC customers must be approved by WSFC Utilities and registered with BSI Online’s bsionlinetracking.com platform. Annual testing is required for commercial and residential fire sprinkler assemblies; residential irrigation assemblies moved to triennial testing per NC SB 166.
Town of Apex
Apex’s cross-connection control program uses TecNXS Inc.’s AquaResource platform (aquaresource.app/portal/11) for electronic test result submission. Only town-approved testers may test assemblies in Apex’s service area. Commercial and residential fire sprinkler assemblies require annual testing. Residential irrigation assemblies are tested every three years with July 31st as the annual submission deadline for the assigned test year. Repair windows: 10 days for health hazard facilities, 30 days for non-health hazard.
Other Major NC Utilities
Union County Water, Aqua North Carolina, Greenville Utilities Commission, Fayetteville PWC, High Point, Greensboro Water Resources, and other North Carolina utilities each operate individual cross-connection control programs. Most have adopted BSI Online, AquaResource, or other digital platforms for test result submission. Annual testing for commercial and industrial is near-universal; residential irrigation moved to triennial per SB 166.
NC SB 166 Changed Residential Irrigation Testing — But Not Commercial
NC Senate Bill 166 (September 2024) reduced residential irrigation backflow testing to every 3 years — but this applies ONLY to residential irrigation systems that do not apply or dispose chemical feeds. All commercial backflow assemblies, all residential fire sprinkler assemblies, and any residential irrigation system with chemical injection capability remain on annual testing schedules. Do not assume the triennial schedule applies to any commercial property simply because it includes irrigation.
Property Owner Compliance Summary for North Carolina
Commercial: Annual testing. Submit results to your utility’s platform (VEPO for Raleigh, BSI Online for WSFC, AquaResource for Apex, etc.).
Residential irrigation: Every 3 years per NC SB 166 (for systems without chemical feeds). Annual deadlines vary by utility — confirm with your utility.
Tester credential: Certified by your specific utility’s approved schools and registered with that utility.
Failed assemblies: Repaired and retested within 15 days (health hazard) or 30 days (non-health hazard).
Assemblies: USC-FCCCHR approved + ASSE standards. RPZ required for residential irrigation (per Raleigh — confirm with your utility).
Find a Certified Backflow Tester in North Carolina
Find utility-approved testers at getyourbackflowtested.com/backflow-testing-near-me/north-carolina-backflow-testing — covering Raleigh, Charlotte, Durham, Winston-Salem, Greensboro, and all major North Carolina markets.
North Carolina Regulatory Reference Links
| Resource / Agency | URL / Link Target |
|---|---|
NCDEQ Division of Water Resources — Cross-Connection Control | |
15A NCAC 18C Rules Governing Public Water Systems — Backflow Appendix | |
NC Senate Bill 166 — Residential Irrigation Testing Change | |
City of Raleigh — Cross-Connection Control Program | |
Raleigh — Backflow Tester Resources | |
Town of Apex — Backflow Prevention | |
Winston-Salem/Forsyth County Utilities — Backflow Prevention |
Related Resources
getyourbackflowtested.com | Backflow Laws — North Carolina Backflow Compliance Guide