🧱 Retaining Wall permit in Delaware
A wall holding back soil where grade changes — height triggers engineering and permit thresholds. Here is the Delaware-specific rule: who issues it, typical fees, timeline, go / no-go, and the official source to verify.
Retaining Wall permit in Delaware
The Delaware rule for a retaining wall, with fee range, timeline, go / no-go, and the official source.
Delaware
🧱 Retaining Wall
Exact permit fees are set by the local building department. WikEst shows the published or code-based range where one exists, linked to its official source — verify the final amount at the source before budgeting.
🧱 Retaining Wall permit fee in Delaware
ConditionalGenerally allowedcounty authority
Permit fee range
Valuation-based when over the height threshold.
Typical timeline
Varies
Setback
—
Exempt if
Retaining walls ≤4 ft above grade and not supporting a surcharge are generally exempt.
Exempt criteria: Retaining walls ≤4 ft above grade (not supporting a driveway, structure, or slope above) are commonly exempt; taller walls require a permit and engineered design.
Expansive clay soils and high water tables affect wall design.
Official sources: Delaware Code — Title 16, Chapter 76 (County/Municipal Building Codes) · Kent County, DE — Adopted Building Codes · City of Wilmington — Land Use & Planning (Permits)
Representative cities for Delaware: Wilmington, Dover.
All 20 project fee ranges in Delaware
Official-source ranges where published; “By local jurisdiction” means no flat fee is published and the amount is set case by case.
| Project | Permit? | Authority | Fee range | Go / no-go |
|---|---|---|---|---|
| 🏠 Accessory Dwelling Unit (ADU) | yes | county | Valuation-based; set by the county (unincorporated) or city. | case-by-case |
| 🪵 Deck / Porch | conditional | county | Valuation-based; set by the county or city. | allowed |
| 🧱 Fence / Wall | conditional | county | Usually no building permit for fences ≤6–7 ft; zoning/height rules apply. | allowed |
| 🛖 Shed / Outbuilding | conditional | county | Valuation-based; set by the county or city. | allowed |
| 🪜 Basement Finish | yes | county | Valuation-based; includes trade permits. | allowed |
| 🚗 Garage / Carport | yes | county | Valuation-based; includes trade permits. | allowed |
| ☀️ Rooftop Solar PV | yes | county | Building + electrical permits; fee set by the county or city. | allowed |
| 🌡️ HVAC Replacement | conditional | county | Mechanical permit; fee set by the county or city. | allowed |
| 🍳 Kitchen Remodel | conditional | county | Valuation-based when structural, plumbing, or electrical work is included. | allowed |
| 🛁 Bathroom Remodel | conditional | county | Valuation-based when plumbing is relocated. | allowed |
| 🏗️ Room Addition | yes | county | Valuation-based; includes trade permits. | allowed |
| 🪟 Window / Door Replacement | conditional | county | Usually no fee for in-kind swaps; a permit is needed if the opening is enlarged. | allowed |
| 🏘️ Roof Replacement | conditional | county | Often over-the-counter or exempt for same-footprint re-roof. | allowed |
| 🅿️ Driveway / Parking Pad | conditional | county | Building permit often not required; curb-cut/right-of-way work is separate. | allowed |
| 🏊 Swimming Pool / Spa | yes | county | Valuation-based; includes barrier/fencing and electrical bonding review. | allowed |
| 🧱 Retaining Wall | conditional | county | Valuation-based when over the height threshold. | allowed |
| 💥 Demolition / Teardown | yes | county | Demolition permit fee set by the county (unincorporated) or city. | allowed |
| 🚰 Septic System | yes | state | Septic permit fees set by DNREC; engineered systems cost more. | allowed |
| 🔌 EV Charger | conditional | county | Electrical permit fee set by the county (unincorporated) or city. | allowed |
| ⚡ Standby Generator | yes | county | Electrical (and often mechanical/gas) permit fee set by the county (unincorporated) or city. | allowed |
Delaware rule at a glance
Needs permit
conditional
Issuing authority
county
Typical fee
Valuation-based when over the height threshold.
Typical timeline
Varies
Setback
—
Exempt if
Retaining walls ≤4 ft above grade and not supporting a surcharge are generally exempt.
Expansive clay soils and high water tables affect wall design.
Frequently asked questions
Does a retaining wall need a permit in Delaware?
In Delaware, a retaining wall is conditional / size-dependent. Issuance is at the county level. Confirm the exact threshold with the local building department using the sources on this page.
Who issues the retaining wall permit in Delaware?
Delaware permits for this project are handled at the county level — usually the city or county building department. Use the county permit authority lookup to find the exact office for your property.
How much does a retaining wall permit cost in Delaware?
Fees are set locally in Delaware and are not a single statewide number. Open the official authority link on this page for the current schedule.
What exemptions apply to a retaining wall in Delaware?
A common threshold: Retaining walls ≤4 ft above grade and not supporting a surcharge are generally exempt.. Retaining walls ≤4 ft above grade (not supporting a driveway, structure, or slope above) are commonly exempt; taller walls require a permit and engineered design. City or county amendments may apply — verify locally.
🗺️ All projects in Delaware
The full Delaware permit guide across 20 home projects.
📊 Retaining Wall in every state
Compare the retaining wall rule across all U.S. states.
Retaining Wall in other states
| State | Permit? | Authority | Typical fee | Timeline | Go / No-Go | Key notes |
|---|---|---|---|---|---|---|
| California | Conditional | city | No fee under the exemption; a permit applies if over the threshold. | 2–4 weeks if required. | Generally allowed | Walls over 4 ft or supporting a surcharge (deck, vehicle, structure) require design and a permit. Exempt: Retaining walls ≤4 ft (measured bottom of footing to top), not supporting a surcharge, are exempt (CBC R105.2). |
| Texas | Conditional | city | No fee under the exemption; a permit applies if over the threshold. | 2–4 weeks if required. | Generally allowed | Taller walls or walls supporting a surcharge (driveway, structure, slope above) require design and a permit. Exempt: Retaining walls not over 4 ft (bottom of footing to top) are exempt (Dallas; IRC 105.2). |
| Florida | Conditional | city | No fee under the exemption; a permit applies if over the threshold. | 2–4 weeks if required. | Generally allowed | Taller or surcharge-supporting walls need design and a permit. Exempt: Retaining walls ≤4 ft (bottom of footing to top), not supporting a surcharge, are exempt (FBC R105.2). |
| New York | Conditional | city | No fee under the exemption; a permit applies if over the threshold. | 2–4 weeks if required. | Generally allowed | Taller or surcharge-supporting walls need design and a permit. Exempt: Retaining walls ≤4 ft (bottom of footing to top), not supporting a surcharge, are exempt (RCNYS R105.2). |
| Pennsylvania | Conditional | city | — | — | Generally allowed | Height and whether the wall supports a surcharge (driveway, structure, or slope above) determine the permit threshold. Verify with your municipality. |
| Illinois | Conditional | city | — | — | Generally allowed | Height and whether the wall supports a surcharge (driveway, structure, or slope above) determine the permit threshold. Verify with your municipality. |
| Ohio | Conditional | city | Columbus minimum permit fee $125 where a permit is required. | — | Generally allowed | Height and whether the wall supports a surcharge (driveway, structure, or slope above) determine the permit threshold. Verify with your municipality. |
| Georgia | Conditional | city | Atlanta minimum permit cost $150 plus $25 fee where a permit is required. | — | Generally allowed | Height and whether the wall supports a surcharge (driveway, structure, or slope above) determine the permit threshold. Verify with your municipality. |
| North Carolina | Conditional | city | Building permit where required; verify with the city. | 1–3 weeks; walls over threshold may need engineered drawings. | Generally allowed | Retaining walls holding more than 48 in of fill (measured bottom of footing to top of fill) require a permit and often professional design. Check HOA too. Exempt: Charlotte/Cary: walls retaining >48 in (4 ft) of fill require a permit. |
| Michigan | Conditional | city | Building permit where required; verify with the city. | 1–3 weeks; walls over threshold may need engineered drawings. | Generally allowed | Retaining walls holding more than 4 ft of fill require a permit and often professional design. Check HOA and drainage too. Exempt: State R105.2 exempts retaining walls ≤4 ft measured from bottom of footing to top (unless supporting a surcharge). |
| New Jersey | Conditional | city | Construction permit where required; verify with the city. | 1–3 weeks; walls over threshold may need engineered drawings. | Generally allowed | Retaining walls over ~4 ft require a UCC construction permit and often professional design. Check HOA and drainage/erosion rules. Exempt: Newark: retaining walls over 4 ft require a UCC construction permit. |
| Virginia | Conditional | city | Building permit where required; verify with the city. | 1–3 weeks; walls over threshold may need engineered drawings. | Generally allowed | Retaining walls holding more than 3 ft of unbalanced fill require a permit and often professional design. Tiered walls have special rules. Check HOA too. Exempt: VUSBC exempts retaining walls supporting <3 ft (36 in) of unbalanced fill. Over 3 ft requires a permit. |
| Washington | Conditional | city | Valuation-based when over the height threshold. | Over-threshold walls need plan review. | Generally allowed | Walls in Environmentally Critical Areas need a pre-application site visit. Exempt: Walls <4 ft from bottom of footing are generally exempt. |
| Arizona | Conditional | city | Valuation-based when over the height threshold. | Over-threshold walls need plan review. | Generally allowed | Walls in hillside/overlay zones have stricter rules. Exempt: Walls ≤30 in above grade and not supporting a surcharge are often exempt. |
| Massachusetts | Conditional | city | Valuation-based when over the height threshold. | Over-threshold walls need plan review. | Generally allowed | Walls in wetland or steep-slope areas may trigger additional review. Exempt: Walls <4 ft from bottom of footing to top are exempt (780 CMR R105.2). |
| Tennessee | Conditional | city | Valuation-based when over the height threshold. | Over-threshold walls need plan review. | Generally allowed | Walls in steep-slope or karst/expansive-soil areas may trigger soils review. Exempt: Walls ≤4 ft (Nashville) / ≤3 ft (Memphis) are exempt unless supporting a surcharge. |
| Indiana | Conditional | city | — | — | Generally allowed | Height and whether the wall supports a surcharge (driveway, structure, or slope above) determine the permit threshold. Verify with your building department. |
| Missouri | Conditional | city | No fee under the exemption; a permit applies if over the threshold. | Varies by municipality — if required, typically several weeks. | Generally allowed | Walls over 4 ft or supporting a surcharge require design and a permit. Verify with your municipal building department. Exempt: Retaining walls ≤4 ft (not supporting a surcharge) are exempt under the locally adopted IRC R105.2. |
| Maryland | Conditional | city | — | — | Generally allowed | Height and surcharge determine the threshold. Annapolis requires sheeting/shoring permits for adjacent excavations. Verify with your city. |
| Wisconsin | Conditional | city | No fee under the exemption; a permit applies if over the threshold. | Varies by municipality — if required, typically several weeks. | Generally allowed | Walls over 4 ft or supporting a surcharge require design and a permit. Verify with your municipal building inspection department. Exempt: Retaining walls ≤4 ft (not supporting a surcharge) are exempt (UDC references IRC R105.2). |
| Alaska | Conditional | city | Valuation-based when over the height threshold. | — | Generally allowed | Frost heave and drainage are major design factors for retaining walls in Alaska. Exempt: Retaining walls ≤4 ft above grade and not supporting a surcharge are generally exempt. |
| Alabama | Conditional | city | Valuation-based when over the height threshold. | — | Generally allowed | Expansive-clay sites may require drainage design even for lower walls. Exempt: Retaining walls ≤4 ft above grade and not supporting a surcharge are generally exempt. |
| Arkansas | Conditional | city | Valuation-based; Little Rock minimum building-permit fee $50 (work over $5,000 or requiring inspection). | — | Generally allowed | Expansive clay soils in the Delta and rocky soils in the northwest affect wall design. Exempt: Walls >4 ft require a permit; Little Rock requires an engineered plan for walls over 4 ft. |
| Colorado | Conditional | city | Valuation-based when over the height threshold. | — | Generally allowed | Sloped mountain lots often trigger engineered retaining-wall requirements. Exempt: PPRBD requires a permit for retaining walls >4 ft; walls ≤4 ft not supporting a surcharge are generally exempt. |
| Connecticut | Conditional | city | Valuation-based when over the height threshold. | — | Generally allowed | Hillside lots may require engineered retaining-wall design. Exempt: Retaining walls ≤4 ft above grade and not supporting a surcharge are generally exempt. |
| Hawaii | Conditional | county | Valuation-based when over the height threshold. | Over-threshold walls need plan review. | Generally allowed | Walls in hillside/SMA zones have stricter rules. Verify with the county building department. Exempt: Walls with ≤3 ft of retained earth and ≤6 ft total height (not supporting a surcharge or impounding liquids) are exempt. |
| Iowa | Conditional | city | Valuation-based when over the height threshold; Cedar Rapids charges a flat $25 retaining-wall permit. | Over-threshold walls need plan review. | Generally allowed | Taller or surcharge-supporting walls require a sealed design. Exempt: Walls 4 ft or less above grade and not supporting a surcharge are typically exempt. |
| Idaho | Conditional | city | Valuation-based when over the height threshold. | Over-threshold walls need plan review. | Generally allowed | Walls in hillside/WUI zones have stricter rules. Verify with the local building department. Exempt: Walls ≤4 ft (measured from bottom of footing to top) and not supporting a surcharge are commonly exempt. |
| Kansas | Conditional | city | Valuation-based when over the height threshold. | Over-threshold walls need plan review. | Generally allowed | Taller or surcharge-supporting walls require a sealed design. Exempt: Overland Park: retaining walls 48 in or higher require a permit with a sealed engineered design. Walls 4 ft or less are typically exempt under the IRC. |
| Kentucky | Conditional | city | Valuation-based when over the height threshold. | Over-threshold walls need plan review. | Generally allowed | Taller or surcharge-supporting walls require a sealed design. Exempt: Walls 4 ft or less above grade and not supporting a surcharge are typically exempt under the KRC. |
| Louisiana | Conditional | city | Valuation-based when over the height threshold. | Over-threshold walls need plan review. | Generally allowed | Taller or surcharge-supporting walls require a sealed design; floodplain properties need extra review. Exempt: NOLA exempts retaining walls not over 3 ft; taller walls require a permit. |
| Maine | Conditional | city | Valuation-based when over the height threshold. | Over-threshold walls need plan review (1–4 weeks). | Generally allowed | Walls in shoreland zones or supporting a driveway/structure usually need a permit regardless of height. Verify with the Code Enforcement Officer. Exempt: Walls ≤4 ft measured from bottom of footing to top are exempt (unless supporting a surcharge). |
| Minnesota | Conditional | city | No fee under the exemption; a permit applies if over the threshold. | Varies by municipality — if required, typically several weeks. | Generally allowed | Walls over 4 ft or supporting a surcharge require design and a permit. Verify with your municipal building department. Exempt: Retaining walls not over 4 ft (measured from bottom of footing to top) and not supporting a surcharge are exempt (Minnesota Residential Code, based on IRC R105.2). |
| Mississippi | Conditional | city | Where enforced, a permit applies if over 4 ft; verify locally. | Varies by jurisdiction. | Generally allowed | Walls over 4 ft or supporting a surcharge require a permit. Confirm with your local building department. Exempt: Where a code is enforced (IRC), retaining walls not over 4 ft (bottom of footing to top) and not supporting a surcharge are exempt. |
| Montana | Conditional | city | Where enforced, a permit applies if over 4 ft; verify locally. | Where enforced, often over-the-counter to a few weeks. | Generally allowed | Walls over 4 ft or supporting a surcharge require a permit. Confirm with your local building department. Exempt: Retaining walls not over 4 ft (bottom of footing to top) and not supporting a surcharge are exempt (2021 IRC R105.2). |
| North Dakota | Conditional | city | — | — | Generally allowed | Deep frost and expansive soils make proper footing design critical. Verify the threshold with your building department. Exempt: Retaining walls not over 4 ft (bottom of footing to top) are exempt (IRC R105.2). |
| Nebraska | Conditional | city | No fee under the exemption; a permit applies if over the threshold. | Varies by municipality — if required, typically several weeks. | Generally allowed | Walls over 4 ft or supporting a surcharge require design and a permit. Verify with your municipal building department. Exempt: Retaining walls not over 4 ft (bottom of footing to top) and not supporting a surcharge are exempt (2018 IRC R105.2). |
| New Hampshire | Conditional | city | — | — | Generally allowed | Local towns may set a stricter height (e.g., Plaistow lists hardscaping under 6 ft as exempt from a building permit). Verify with your building department. Exempt: Retaining walls not over 4 ft (measured bottom of footing to top) are exempt. |
| New Mexico | Conditional | city | — | — | Generally allowed | The CID requires a professional seal for retaining walls over 4 ft. Verify the threshold with your building department. Exempt: Retaining walls not over 4 ft (bottom of footing to top) are exempt (NM Residential Code §105.2(3)). |
| Nevada | Conditional | city | Valuation-based when over the height threshold. | Over-threshold walls need plan review (engineering for surcharge/wind). | Generally allowed | Walls supporting a surcharge (driveway, slope, structure) or in hillside/grading zones require engineered design. Exempt: Clark County exempts retaining walls up to 24 in; IRC R105.2 exempts retaining walls ≤4 ft not supporting a surcharge. |
| Oklahoma | Conditional | city | Valuation-based when over the height threshold. | Over-threshold walls need plan review (engineering for surcharge/wind). | Generally allowed | Expansive-clay soils and wind loading make engineered design important for taller walls. Exempt: Retaining walls ≤4 ft above grade (not supporting a surcharge) are exempt (IRC R105.2); OKC requires a permit for masonry/retaining walls over 4 ft. |
| Oregon | Conditional | city | Valuation-based when over the height threshold. | Over-threshold walls need plan review (engineering for surcharge). | Generally allowed | Oregon’s hillside/seismic conditions make engineered design important for taller walls. Exempt: Retaining walls >4 ft, or supporting a slope/drive/structure, require a permit (Portland). |
| Rhode Island | Conditional | city | Valuation-based when over the height threshold (statewide formula, $125 min). | Over-threshold walls need plan review (engineering for surcharge). | Generally allowed | Rhode Island’s threshold (32 in) and the cast-in-place concrete carve-out (24 in) differ from the base IRC (4 ft) — a key state-specific rule. Exempt: Rhode Island exempts retaining walls ≤32 in (measured from lower finished grade to top), unless supporting a surcharge. |
| South Carolina | Conditional | city | Valuation-based when over the height threshold. | Over-threshold walls need plan review (engineering for surcharge). | Generally allowed | Coastal grading and floodplain/drainage rules can affect wall design; engineered retaining may be required in higher hazard areas. Exempt: S.C. Code § 40-59-265 exempts retaining walls not over 4 ft measured from bottom of footing to top, unless supporting a surcharge. |
| South Dakota | Conditional | city | Valuation-based when over the height threshold. | Over-threshold walls need plan review. | Generally allowed | Walls in hillside or drainage-path areas have stricter rules; verify with the building department. Exempt: Walls ≤4 ft above grade and not supporting a surcharge are exempt under IRC R105.2. |
| Utah | Conditional | city | Valuation-based when over the height threshold. | Over-threshold walls need plan review. | Generally allowed | Walls in hillside or drainage-path areas have stricter rules; verify with the building department. Exempt: Walls ≤4 ft above grade and not supporting a surcharge are exempt under IRC R105.2. |
| Vermont | Conditional | city | Valuation-based when over the height threshold, where enforced. | Over-threshold walls need plan review where enforced. | Generally allowed | Walls in hillside or drainage-path areas have stricter rules; verify with the town. Exempt: Walls ≤4 ft above grade and not supporting a surcharge are exempt under IRC R105.2. |
| West Virginia | Conditional | city | Valuation-based when over the height threshold. | Over-threshold walls need plan review. | Generally allowed | Walls in hillside or drainage-path areas have stricter rules; verify with the building department. Exempt: Walls ≤4 ft above grade and not supporting a surcharge are exempt under IRC R105.2. |
| Wyoming | Conditional | city | Valuation-based when over the height threshold, where enforced. | Over-threshold walls need plan review where enforced. | Generally allowed | Walls in hillside or drainage-path areas have stricter rules; verify with the building department. Exempt: Walls ≤4 ft above grade and not supporting a surcharge are exempt under IRC R105.2. |