Delaware (DE) Plumbing Code & Permit Rules
International Plumbing Code (2021) · Updated 2026-05-31
Data: State plumbing boards, ICC, IAPMO, EPA Last verified: 2026-05-31
Delaware requires licensed plumbers for most plumbing work and mandates annual backflow testing. These regulations help protect water quality but mean higher costs for homeowners compared to states that allow DIY work.
Plumbing Code
Delaware follows the International Plumbing Code (2021 edition).
Key Regulations
| Regulation | Status | Details |
|---|---|---|
| Plumbing Code | IPC (2021) | International Plumbing Code |
| Homeowner DIY | Not allowed | Licensed plumber required |
| Water Heater Permit | Required | |
| Backflow Testing | Annual, required | |
| Seismic Strapping | Not required | Water heater restraint |
DIY Plumbing in Delaware
Delaware requires a licensed plumber for most plumbing work. Licensed plumber required
While this increases costs, it ensures:
- Work meets current code requirements
- Proper permitting and inspection
- Warranty and liability protection
- Safe connections to water and sewer systems
Backflow Prevention
Delaware requires annual backflow testing to protect the public water supply from contamination. Testing must be performed by a Certified tester.
Non-compliance penalty: Water service may be shut off if testing is not completed on schedule.
Water Conservation Requirements
Delaware follows federal water conservation standards. Federal minimums apply
Lead Service Line Replacement
Delaware has an active lead service line replacement program. Following EPA Lead and Copper Rule 2021
Data Sources
- Delaware state plumbing board and licensing agency
- International Code Council (ICC)
- IAPMO
- EPA Safe Drinking Water Act
Updated as regulations change.
Need a licensed plumber in Delaware?
Plumbing regulations vary by city. Connect with a licensed professional who knows your local code requirements.
Find a Licensed Plumber →Frequently Asked Questions
What plumbing code does Delaware follow?
Delaware follows the International Plumbing Code (2021 edition).
Can I do my own plumbing work in Delaware?
No, Delaware requires a licensed plumber for most plumbing work.
Do I need a permit to replace a water heater in Delaware?
Yes, Delaware requires a permit for water heater replacement. A licensed plumber is required for the installation.
Is backflow testing required in Delaware?
Yes, Delaware requires annual backflow testing.
Does Delaware require seismic strapping for water heaters?
No, Delaware does not require seismic strapping for water heaters. However, they remain a prudent option in areas with seismic activity.