Delaware permit requirements

We have read and dated 26 permit rules across 2 jurisdictions in Delaware. They do not agree with each other: on deck, fence and HVAC work the answers change depending on which Delaware jurisdiction you are in.

Jurisdictions: 2
Verified rules: 26
Permit always required: 14
Depends on the project: 12

Do you need a building permit in Delaware?

Usually yes, but not from Delaware itself: permits are issued by the city or county, not the state, so the rule that governs your project is the one your own jurisdiction publishes. 14 of those local rules require a permit outright, 12 depend on a size or scope condition the office publishes, and 0 need none. Delaware sets the building code those local rules derive from; your city or county sets the threshold and the fee.

Where Delaware jurisdictions split

The verdict for each project across the 2 Delaware jurisdictions we cover. On 8 of 13 projects they do not give the same answer, which is why a statewide answer is not one.

Project	Permit required	Depends	Across the state
Deck	1	1	Answer varies
Fence	1	1	Answer varies
HVAC	1	1	Answer varies
Patio	1	1	Answer varies
Pool	1	1	Answer varies
Shed	1	1	Answer varies
Solar	1	1	Answer varies
Water Heater	1	1	Answer varies
Bathroom Remodel		2	Same answer everywhere
Electrical	2		Same answer everywhere
EV Charger	2		Same answer everywhere
Plumbing	2		Same answer everywhere
Roof Replacement		2	Same answer everywhere

Building without a permit in Delaware

Delaware sets no single statewide fine for building without a permit. Instead, Title 9 of the Delaware Code gives each of the three counties its own building permit chapter, and the penalty depends on where the work sits.

Penalties, the as-built path, and what the statute actually says

What you can build without a permit in Delaware

0 of the 26 answered rules across Delaware need no permit at all and 12 turn on a size or scope condition the jurisdiction publishes, by project and jurisdiction, in each office's own words.

The exemptions and conditions, jurisdiction by jurisdiction

What each Delaware jurisdiction publishes

One line per jurisdiction, written from its own rules rather than from a state summary. This is the section that used to be a list of links, and the states with the fewest jurisdictions to compare are the ones it says the most about.

New Castle County 13 rules
5 of 13 projects always need a permit and 8 turn on the size or scope of the work. Published thresholds include deck at 200 sq ft and patio at 30 inches.
Sussex County 13 rules
9 of 13 projects always need a permit and 4 turn on the size or scope of the work. The ones that depend on the project are bathroom remodel, HVAC, roof replacement and water heater.