Solar Permit in New Castle County, Delaware
It depends
Sometimes, depending on the project
Ground-mounted arrays and non-residential systems need a County building permit; every system needs State electrical inspection.
Issued byNew Castle County Department of Land Use
By Mario Bailey, verified against official sources
Quick answer
New Castle County exempts the installation of rooftop solar panels on one- and two-family dwellings from its building permit. The County does not permit or inspect electrical work, so the electrical side of a solar installation is inspected through a Delaware-licensed electrical inspection agency (or a State homeowner permit). Ground-mounted arrays are not covered by the rooftop exemption.
Typical threshold: Rooftop panels on a one- or two-family dwelling are exempt from the County building permit; electrical work still goes through the State.
Who is pulling this permit?
Apply yourself
Hire it out
Before you sign, ask the contractor:
- Who pulls the permit, you or me, and is the permit fee included in the bid?
- Which inspections will this job need, and who meets the inspector on site?
Delaware's owner-builder rule (9 Del. C. 6302(b); 9 Del. C. 4402(b); 24 Del. C. 1417; 24 Del. C. 1807(c)(2); 24 Del. C. 1820(c)(2); 16 Del. C. 7906(c)) sets what you may do on your own home without hiring anyone. Read the statute.
When a permit is usually needed
Ground-mounted arrays and non-residential systems need a County building permit; every system needs State electrical inspection.
What a solar permit costs in New Castle County
How to apply in New Castle County
In New Castle County, a rooftop solar PV permit application is a combined structural and electrical plan set: a site plan and roof framing details proving the array's mounting can carry its added loads, plus a one line electrical diagram covering listed modules and inverters, disconnects, and the rapid shutdown design. Utility interconnection is a separate approval that runs in parallel with the permit.
What most solar permit applications include:
- Both a building permit and a separate electrical permit are required, since the array must be designed and installed to the residential code's solar provisions and to the National Electrical Code (IRC R324.3).
- For New Castle County, the plan set identifies listed equipment: PV modules listed to UL 1703 (or both UL 61730-1 and UL 61730-2), and inverters listed to UL 1741, with grid-tied inverters listed for utility interaction (IRC R324.3.1).
- Structural drawings show that the roof framing is designed to structurally support the array and withstand the gravity loads it adds (IRC R324.4.1).
- For New Castle County, the site plan lays out roof access pathways at least 36 inches wide, plus a ridge setback sized to how much of the roof the array covers, so firefighters retain pathways and ventilation access (IRC R324.6.1, IRC R324.6.2).
- For New Castle County, the one line electrical diagram shows the rapid shutdown method and the location of its single initiation device, since one control point must bring all system conductors down to safe levels (NEC 690.12, NEC 690.56(C)).
- Interconnecting the array to the utility grid at a defined point of connection is a separate application process from the local building or electrical permit and must be approved before the system can operate (NEC 705.12).
- Some permitting offices route applications through SolarAPP+, an automated review platform that checks the plan set against code requirements and issues eligible permits instantly (DOE SolarAPP+).
General submittal guidance from IRC 2021 R324 (Solar Energy Systems) and NEC 2020 Article 690 (Solar Photovoltaic Systems) and Article 705 (Interconnected Power Production Sources). Source. New Castle County Department of Land Use sets the exact checklist for New Castle County.
Where to apply in New Castle County:
New Castle County Department of Land Use
- New Castle County Government Center, 87 Reads Way, New Castle, DE 19720
- Phone: 302-395-5400
- Email: permits@newcastlede.gov
Solar Permit in New Castle County compared with nearby Delaware localities
| Locality | Permit needed? | Threshold | What each Delaware schedule says | Verified |
|---|---|---|---|---|
| New Castle County | It depends | Rooftop panels on a one- or two-family dwelling are exempt from the County building permit; electrical work still goes through the State | Not published | |
| Sussex County | Permit required | Any size | ...County Building Permit Fee Guide: construction value (table rates such as... |
Inspections and closing out your permit
In New Castle County, inspectors verify the installed array against the approved plans, and some agencies run a rough check of roof attachments and penetrations while they are still exposed before the wiring and roofing close them in. The final inspection confirms rapid shutdown, disconnects, grounding, and required labels are installed correctly, and the system cannot be energized until the utility separately approves interconnection.
- In New Castle County: where an agency runs a rough or pre-inspection, it checks the array's roof penetrations while they are still exposed, confirming they are flashed and sealed (IRC R324.4.3).
- In New Castle County: the inspector confirms whether rapid shutdown is required, how it is accomplished, and that it is properly identified (NEC 690.12, NEC 690.56(C)).
- In New Castle County: pV disconnecting means must be permanently marked and installed where they are readily accessible, which the inspector confirms in the field (NEC 690.13).
- In New Castle County: bonding and grounding of the array, including every exposed non current carrying metal part and the grounding electrode system, is checked before sign off (NEC 690.43, NEC 690.47).
- In New Castle County: at the service equipment, the inspector looks for the required rapid shutdown placard, a labeled diagram showing the initiation device's location in the specified colors and letter sizes (NEC 690.56(C)).
- In New Castle County: utility interconnection is inspected and approved separately from the local building department's sign off, and the system cannot be energized until both approvals are in hand (NEC 705.12).
Schedule each inspection in advance and pass the final before you use the work or close the permit. Request inspections through the New Castle County permit portal or by phone at 302-395-5400.
Inspection sequence from NEC 2020 Article 690 (690.12 rapid shutdown, 690.13 disconnects, 690.43/690.47 grounding, 690.56 labeling) and IRC 2021 R324.4.3 (roof penetrations). Source. An open permit left un-inspected can surface later in a title search or home sale.
Your Solar Permit checklist for New Castle County
- Confirm the requirement. Sometimes, depending on the project. Typical threshold: Rooftop panels on a one- or two-family dwelling are exempt from the County building permit; electrical work still goes through the State. Usually needed: Ground-mounted arrays and non-residential systems need a County building permit; every system needs State electrical inspection.
- Budget the fee. Check the official fee schedule for current amounts.
- Apply. In New Castle County, a rooftop solar PV permit application is a combined structural and electrical plan set: a site plan and roof framing details proving the array's mounting can carry its added loads, plus a one line electrical diagram covering listed modules and inverters, disconnects, and the rapid shutdown design. Utility interconnection is a separate approval that runs in parallel with the permit. Start at the New Castle County permit portal.
- Keep the office details handy. New Castle County Department of Land Use. Phone: 302-395-5400. Address: New Castle County Government Center, 87 Reads Way, New Castle, DE 19720.
- Plan for inspections. In New Castle County, inspectors verify the installed array against the approved plans, and some agencies run a rough check of roof attachments and penetrations while they are still exposed before the wiring and roofing close them in. The final inspection confirms rapid shutdown, disconnects, grounding, and required labels are installed correctly, and the system cannot be energized until the utility separately approves interconnection.
Compiled from the official sources on this page. Last checked .
Frequently asked questions
- Do you need a solar permit in New Castle County?
- New Castle County exempts the installation of rooftop solar panels on one- and two-family dwellings from its building permit. The County does not permit or inspect electrical work, so the electrical side of a solar installation is inspected through a Delaware-licensed electrical inspection agency (or a State homeowner permit). Ground-mounted arrays are not covered by the rooftop exemption. Rooftop panels on a one- or two-family dwelling are exempt from the County building permit; electrical work still goes through the State. Always confirm with the office before starting.
- How much does a solar permit cost in New Castle County?
- Fees are set by New Castle County and are not published here. See the official fee schedule for current amounts.
- Where do you apply for a solar permit in New Castle County?
- You can apply through the New Castle County permit portal or contact the New Castle County Department of Land Use directly. The links are listed on this page.
- Can a homeowner pull a solar permit themselves in New Castle County?
- Under Delaware law (9 Del. C. 6302(b); 9 Del. C. 4402(b); 24 Del. C. 1417; 24 Del. C. 1807(c)(2); 24 Del. C. 1820(c)(2); 16 Del. C. 7906(c)): Yes. Delaware homeowners may pull permits and do their own work, with trade-specific conditions. Sussex County's statute expressly lets any owner who wants to do their own work on their own building get a permit, and Kent County issues permits in the owner's name. For electrical work, a homeowner wiring their own home that is not for sale or rent must get a homeowner's permit from the Board of Electrical Examiners and pass a final inspection; swimming pools and hot tubs are excluded. Homeowners may do their own plumbing and HVACR work (but not gas piping) in their own home that is not for sale, rent or lease, and for plumbing must file a permit application with the inspection authority. Confirm how New Castle County applies this before you apply.
From the Library
What else needs a permit in New Castle County
Every other permit type we have verified for this jurisdiction, with the rule that applies here.
| Project | Permit needed? | Threshold | Typical fee |
|---|---|---|---|
| Bathroom Remodel Permit | It depends | Finish work (tiling, cabinets, counter tops) and in-place fixture reinstallation are exempt; new or moved plumbing, walls or circuits are not | 11/04/2025): "Building Permit Fee: $12 per $1,000 of Valuation ($142 Minimum)"... |
| Deck Permit | It depends | Floor area of a free-standing deck no more than 30 inches above grade and not adjacent to or attached to the dwelling | 11/04/2025): "Building Permit Fee: $12 per $1,000 of Valuation ($142 Minimum)"... |
| Electrical Permit | Permit required | Any size | See schedule |
| EV Charger Permit | Permit required | Any size | See schedule |
| Fence Permit | It depends | Only fences that serve as swimming pool barriers need a permit | Not published |
| HVAC Permit | Permit required | Any size | ...6 Schedule of Permit and Review Fees, as amended through January 1, 2026): $5.25... |
| Patio Permit | It depends | Height of a non-structural slab, patio or decorative hardscaping at any point | Not published |
| Plumbing Permit | Permit required | Any size | ...6 Schedule of Permit and Review Fees, as amended through January 1, 2026): $5.25... |
| Pool Permit | It depends | Pool, spa or hot tub wall height; any pool designed to connect to a circulation system needs a permit regardless of height | 11/04/2025): "Building Permit Fee: $12 per $1,000 of Valuation ($142 Minimum)"... |
| Roof Replacement Permit | It depends | Share of the roof sheathing repaired or replaced during a re-roof | 11/04/2025): "Building Permit Fee: $12 per $1,000 of Valuation ($142 Minimum)"... |
| Shed Permit | It depends | Floor area of a one-story detached accessory structure with an eave height of 10 feet or less and overall height of 20 feet or less; garages never qualify | 11/04/2025): "Building Permit Fee: $12 per $1,000 of Valuation ($142 Minimum)"... |
| Water Heater Permit | Permit required | Any size | ...6 Schedule of Permit and Review Fees, as amended through January 1, 2026): $5.25... |
Solar Permit in other Delaware localities
Everything above, sourced
Code references
National and state model-code sections the general guidance on this page is drawn from. They are not New Castle County documents; the office above sets the local rules.
How this solar permit page for New Castle County was verified. 2 official sources: newcastlede.gov, newcastlede.gov; fee schedule: official document. Last checked by Mario Bailey, not confirmed with New Castle County Department of Land Use. Rules change; confirm before you build. How we verify.
Last checked: Report an error on this page
Compare Solar Permit requirements across Delaware localities