Delaware backflow testing rules
Under 16 Del. Admin. Code 4462-21.1.1 (Division of Public Health), a public water system may not serve premises with cross-connections unless they are eliminated or controlled to the satisfaction of the water system and the Division.
Who sets the rules in Delaware
Every public water system must have a plan for a comprehensive cross-connection control program, sized to the system and its customers (4462-21.2.1).
Each program is run by a person the water system designates who is trained and experienced in cross-connection control (4462-21.2.1).
Backflow prevention assemblies must meet ASSE, AWWA and ASME standards (4462-21.3.1).
Delaware's plumbing code is the International Plumbing Code, and every county, city and town must enforce it (16 Del. Admin. Code 4455-1.0).
A new backflow prevention assembly that connects to the drinking water supply needs a plumbing permit (4455-2.0, amendment to IPC 106.2).
Sources: No public water system may serve premises with uncontrolled cross-connections; Delaware's plumbing code is the 2021 IPC, enforced by every county and city
Is an annual test required?
Delaware's plumbing code requires owners of backflow assemblies to test them at least once a year (16 Del. Admin. Code 4455-2.0, amendment to IPC 312.10.2).
Source: Owners must test backflow assemblies at least annually
Which properties need a backflow preventer
An approved backflow assembly or elimination method is required at premises with an auxiliary water system and the other conditions the rule lists (4462-21.2.4.1).
High hazard premises need an assembly, including farms and dairies, bottling and food plants, car washes, chemical plants, dry cleaners, laboratories, medical facilities, metal platers, mortuaries, petroleum plants, marinas and wastewater plants (4462-21.2.4.2).
Premises that cannot be surveyed, or that have a history of cross-connections, are also covered (4462-21.2.4.4 and 21.2.4.5).
For low hazard premises, a water system may use a public education program instead of assemblies (4462-21.2.5).
Home fire sprinkler systems on drinking water piping need no backflow device unless they connect to a fire department connection or contain antifreeze (4455-2.0, amendment to IPC 608.17.4).
Sources: An approved assembly is required at premises with an auxiliary water system; Home fire sprinklers on potable piping need no backflow device unless they have a fire department connection or antifree
How the test report is filed
The state plumbing program inspects the first installation of an assembly but does not track or enforce later tests; local jurisdictions may add requirements (4455-2.0).
Water systems keep backflow test records for at least 10 years (4462-21.4.1).
Sources: The state plumbing program inspects the first installation but does not track later tests; Water systems keep backflow test records for at least 10 years
If a test is missed
A water system may shut off service until a cross-connection problem is corrected (4462-21.1.4).
Violations of the drinking water regulations carry penalties under 16 Del. C. 122(3)c (4462-21.6).
Source: Service may be shut off until a cross-connection is corrected
Common questions
Is backflow testing required every year in Delaware?
Yes. Delaware's plumbing code (16 Del. Admin. Code 4455, amendment to IPC 312.10.2) requires owners of backflow assemblies to test them at least once a year.