Delaware Plumbing Inspection: Process, Fees, and Re-Inspection Rules

Inspections Are Managed Locally, Not by the State Licensing Board

The Division of Professional Regulation issues your Master Plumber license, but they don't inspect your work. Plumbing inspections in Delaware are handled by whichever local Authority Having Jurisdiction covers the job site — the Division of Public Health in unincorporated Kent and Sussex County areas, New Castle County's Department of Land Use, or the municipal inspection departments in Wilmington, Dover, and Newark.

Each authority runs its own scheduling system, charges its own fees, and enforces the 2021 International Plumbing Code (IPC) with Delaware-specific amendments. Getting the process wrong doesn't just delay the project — it can trigger re-inspection fees that eat into your margins.

The Standard Inspection Sequence

Regardless of which jurisdiction manages the inspection, plumbing projects in Delaware generally follow a three-phase sequence:

Rough-in inspection. Conducted after the drain, waste, and vent piping is installed but before walls and ceilings are closed up. The inspector verifies pipe sizing, slope, material compatibility, and code-required clearances. All piping must be pressurized and accessible — if the inspector arrives and finds drywall covering the rough-in, you'll be asked to demo it and reschedule.

Top-out inspection. Covers the water supply distribution system after piping is complete but before fixtures are set. The inspector checks pressure testing, support and securing, and proper valve placement.

Final inspection. Conducted after all fixtures are installed, connected, and operational. The inspector runs water through the system, checks trap seals, verifies temperature-pressure relief valve configurations on water heaters, and confirms that the installation matches the approved permit drawings.

DPH Inspection Rules (Kent and Sussex Counties)

The Division of Public Health manages inspections in areas without local code enforcement departments. Their rules are straightforward:

• Schedule inspections at least three business days in advance
• The first three inspections per permit are included in the $100 permit fee
• Each additional inspection beyond the third costs $50
• The inspector will verify compliance with the 2021 IPC plus Delaware-specific amendments

The three-inspection limit is the most important number to remember. If your rough-in, top-out, and final all pass on the first visit, you pay nothing beyond the original permit fee. But if a rough-in fails and needs a re-inspection, that's your third included visit used up — and the final inspection becomes a $50 charge.

New Castle County Inspections

New Castle County schedules inspections through the eServices portal at ePlans.nccde.org. After submitting your inspection request online, you can track which discipline (zoning, plumbing, fire marshal) has been assigned and contact the reviewer directly through the department directory if there's a delay.

The county enforces the same 2021 IPC with Delaware amendments, but local NCC-specific amendments may apply for projects in the unincorporated county area. Contractors must hold an active NCC business registration before the county will accept inspection requests.

Wilmington Inspections

The City of Wilmington's Department of Licenses and Inspections enforces building subcode compliance alongside the adopted plumbing code. Wilmington runs its own inspection scheduling — separate from NCC — and applies its own fee structure.

The city's $20 base trade permit fee covers the standard inspection sequence. For larger commercial projects calculated on the valuation-based fee schedule ($12 per $1,000 of project value), the inspection cost is wrapped into the overall permit fee. The $50 Certificate of Compliance fee is assessed at project completion.

Dover Re-Inspection Fees

Dover uses an escalating re-inspection fee schedule that makes failed inspections progressively more expensive:

• First re-inspection: free
• Second re-inspection: $25
• Third re-inspection: $50
• Subsequent re-inspections: $100 each

This structure penalizes repeat failures more heavily than a flat re-inspection fee would. A plumber who fails the rough-in twice and then has a final inspection issue could pay $75 in re-inspection fees on top of the original permit cost.

How to Avoid Re-Inspection Charges

Most failed inspections come down to a few preventable issues:

Incomplete work. Calling for an inspection before all required work in that phase is actually finished. If the inspector arrives for a rough-in and finds supply lines not yet pressurized, it counts as a failed inspection even though nothing is technically wrong.

Accessibility. Piping must be visible and accessible at the time of inspection. Covered pipe, cluttered work areas, or locked job sites all result in a failed visit.

Permit mismatch. The installation must match what was submitted on the permit application. Significant changes in fixture count, pipe routing, or equipment specifications need a permit revision before the inspection, not an explanation during it.

Code reference. Delaware enforces the 2021 IPC with state-specific amendments — not the most recent IPC edition and not a generic "national plumbing code." If your work follows a different edition, the inspector will flag the discrepancy.

The Delaware Plumber License Guide includes a jurisdiction-by-jurisdiction inspection directory covering scheduling methods, fee schedules, and the specific portal links for each AHJ in the state.

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