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New Castle County, DE Building Safety: Plumbing Permits (2026)

Some Restrictions
Compiled from the official code textEditor Martyn O'NeillLast verified September 2026

Key Facts

Permit issuer
Code Official, Department of Land Use
Code enforced
Statewide Plumbing Code (International Plumbing Code)
Homeowner exemption
Own home only, not for sale or rent
State authority
16 Del. C. ch. 79
Scope
Unincorporated county; municipalities may opt in

Summary

New Castle County requires a permit before installing, altering, or replacing plumbing systems, but lets homeowners skip contractor licensing by pulling a homeowner's plumbing permit for their own home.

City-specific rules exist: Wilmington has its own plumbing permits rules that differ from New Castle County's county-level regulations. If you live in Wilmington, check the city-specific page instead.

Any permit contractor endorsement holder ... who intends to ... install, alter, repair ... or replace any ... plumbing system ... shall first make application to the Code Official and obtain the required permit. ... Owner-occupier residential plumbing permit. Any person who installs that person's own plumbing work ... in or about that person's own home and not for sale or any part for rent, shall not be required to be licensed as a licensed contractor pursuant to this Section. Homeowners may install plumbing in their private dwellings by obtaining a homeowner's plumbing permit.

View official code

Official source re-checked September 7, 2026: no newer edition of the code had been published (publisher’s edition: Code of Ordinances: Supplement 5).

Full Breakdown

The Department of Land Use enforces the Statewide Plumbing Code -- the International Plumbing Code as adopted and modified by the Delaware Division of Public Health under 16 Del. C. ch. 79 -- and requires a permit from the Code Official before installing, altering, repairing, or replacing a plumbing system. A homeowner doing the work themselves, in a home not for sale or rent, can skip contractor licensing and get a homeowner's plumbing permit instead; gas piping isn't covered by that exemption. This Building Code chapter applies to unincorporated New Castle County and reaches an incorporated municipality only if that municipality's governing body opts in. Wilmington and Newark run their own separate codes.

Violations & Fines

Working without the required permit exposes the permit holder to administrative penalties and fees set by the Code Official, on top of the permit fee itself, per Section 6.03.016(D).

Frequently Asked Questions

Do I need a permit to replace a water heater in New Castle County?
Yes -- plumbing installations and replacements need a permit from the Code Official, though minor repairs like clearing stoppages or refitting an existing fixture in place are exempt under Section 6.03.012(C)(5).
Can I do my own plumbing work in New Castle County?
Yes, if it's your own home and not for sale or rent -- you can skip contractor licensing and get a homeowner's plumbing permit instead, per Section 6.03.012(B)(2).
Does this cover Wilmington or Newark?
No -- Wilmington and Newark are incorporated cities with their own municipal codes and issue their own plumbing permits separately from New Castle County.

Sources & Official References

Other rules in New Castle County

Building PermitsSome RestrictionsCarbon Monoxide DetectorsSome RestrictionsChildcare Center RulesSome RestrictionsGreen Building CodeLight RestrictionsElectrical PermitsSome RestrictionsLead PaintSome RestrictionsBuilding InspectionsSome RestrictionsFire Sprinkler RequirementsFew RestrictionsDoor Locking HardwareSome RestrictionsElevator MaintenanceSome RestrictionsLandscaping Rules: CompostingLight RestrictionsEnvironmental Rules: Coastal DevelopmentSignificant RestrictionsNoise from Specific Sources: Delivery Truck NoiseSome RestrictionsCode Violation Reporting: How to ReportSome RestrictionsWater Use Rules: Leak Reporting DutySome RestrictionsSign Regulations: Window SignsLight Restrictions

All New Castle County rules

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Plumbing Permits in Cities Across New Castle County

Wilmington, DE