Backflow Laws: Delaware
Delaware Backflow Prevention Laws, Regulations, and Compliance Requirements
Delaware's backflow prevention requirements are administered by the Delaware Department of Natural Resources and Environmental Control (DNREC) Division of Water. Delaware is classified nationally as a high-regulation state, requiring a comprehensive cross-connection control plan, regular hazard assessments, and maintenance of all survey and backflow assembly test records for at least 10 years — one of the longest record retention requirements in the nation. This guide covers Delaware's state framework, Artesian Water, SUEZ Water Delaware, and the municipal utilities serving Wilmington and Dover.
Delaware State Regulatory Framework
Delaware’s drinking water program is administered by the Delaware Department of Natural Resources and Environmental Control (DNREC), Division of Water, which holds EPA primacy under the federal Safe Drinking Water Act. Delaware’s cross-connection control requirements are established in the Delaware Regulations Governing Public Drinking Water Systems.
Delaware requires each public water system to develop and maintain a comprehensive cross-connection control program that includes: a written cross-connection control plan; regular hazard assessments of service connections; maintenance of a complete inventory of all backflow prevention assemblies; annual testing of all required assemblies; and record retention of all survey records and backflow assembly test results for a minimum of 10 years. This 10-year record retention requirement is among the most demanding in the United States.
Delaware’s program applies to commercial, industrial, institutional, and multi-family service connections. Single-family residential connections are generally assessed on a case-by-case basis when specific hazards are identified (such as auxiliary water supplies or irrigation systems connected to chemical injection equipment).
Tester Certification in Delaware
Delaware certification requirements are set locally by water purveyors and local jurisdictions — state-level certification is not centrally administered by DNREC for backflow testers. The most widely accepted credentials in Delaware are ASSE 5110 (Backflow Prevention Assembly Tester) and ABPA (American Backflow Prevention Association) certifications. Confirm the specific credential requirements with your water utility before scheduling testing.
Delaware's 10-Year Record Retention Requirement
Delaware’s requirement to retain all survey and backflow assembly test records for a minimum of 10 years is one of the strictest record-keeping requirements among all U.S. states. For commercial property owners, this means maintaining complete test histories for the life of an assembly and beyond, making organized digital recordkeeping essential. Property transactions involving Delaware commercial real estate with backflow assemblies should include a transfer of the complete 10-year compliance record to the new owner.
Major Water Purveyors in Delaware
Artesian Water Company
Artesian Water Company is Delaware’s largest investor-owned water utility, serving approximately 300,000 customers in New Castle County, Kent County, and portions of Sussex County. Artesian administers a cross-connection control program requiring hazard assessments at all commercial and industrial service connections, installation of appropriate backflow assemblies, and annual testing. Artesian’s program aligns with DNREC requirements and includes the 10-year record retention standard. Test results must be submitted to Artesian within their specified window.
SUEZ Water Delaware (formerly United Water Delaware)
SUEZ Water Delaware serves communities in New Castle County including portions of Wilmington’s suburbs. SUEZ operates a cross-connection control program aligned with DNREC requirements. Commercial and industrial customers are required to install approved backflow prevention assemblies and test them annually. SUEZ maintains its own approved tester list and filing procedures.
City of Wilmington Public Works
The City of Wilmington serves its municipality and some adjacent areas. Wilmington’s cross-connection control requirements include annual testing for all commercial and high-hazard connections. Wilmington’s Department of Public Works administers the program. Property owners in Wilmington should confirm specific assembly requirements and filing procedures with the city.
City of Dover Public Utilities
Dover Public Utilities serves the state capital. Commercial and industrial customers in Dover are required to install appropriate backflow assemblies and test them annually. Dover has been actively enforcing cross-connection control compliance as part of broader water system improvement initiatives.
Tidewater Utilities and Smaller Providers
Tidewater Utilities serves communities primarily in Sussex County (southern Delaware). Tidewater operates a cross-connection control program for its service area. Many of Sussex County’s communities are also served by small community water systems with varying program sophistication — property owners should confirm program requirements directly with their specific water system.
Commercial Real Estate Due Diligence in Delaware
Delaware’s 10-year record retention requirement means that any commercial property transaction involving a property with backflow assemblies should include a thorough review of the compliance history. A property with five or more years of test records, filed on time with no lapses, demonstrates strong compliance. A property with gaps in the 10-year record may have unresolved DNREC or utility compliance issues that should be investigated before closing.
Property Owner Compliance Summary for Delaware
Plan: Your water utility maintains the formal DNREC-compliant CCC plan, but your compliance data feeds it.
Assessment: Commercial and industrial connections receive hazard assessments determining required assembly types.
Testing: Annual testing by a credentialed tester accepted by your specific utility. Submit results within the utility’s specified window.
Records: All survey records and test results must be retained for a minimum of 10 years.
Find a Certified Backflow Tester in Delaware
Find credentialed backflow testers approved by Delaware’s major water utilities at getyourbackflowtested.com/backflow-testing-near-me/delaware-backflow-testing — covering Wilmington, Dover, and all Delaware utility service areas.
Delaware Regulatory Reference Links
| Resource / Agency | URL / Link Target |
|---|---|
DNREC Division of Water — Public Drinking Water | |
Delaware Regulations Governing Public Drinking Water Systems | |
Artesian Water Company — Cross-Connection Control | |
SUEZ Water Delaware | |
City of Wilmington Public Works | |
City of Dover Public Utilities |