Do You Need a Permit for a Retaining Wall? Rules in All 50 States

Whether you need a permit for a retaining wall usually comes down to one number: 4 feet. The model residential code exempts shorter walls that don’t hold back a driveway, slope or building. But states adopt that code differently, and some have no statewide residential code at all, so the real answer depends on your state and town. Here’s the rule in all 50 states and D.C.

What counts as a surcharge

A surcharge is any extra load on the soil the wall is holding back: a driveway or parking area, a slope rising above the wall, a building or deck footing, a pool, or another wall above it in a terrace. Codes treat surcharged walls as structural at any height, because that load pushes much harder than flat soil.

Retaining wall permit rules in all 50 states

State	Statewide residential code	Retaining wall permit exemption
Alabama	2015 IRC with Alabama amendments (Alabama Residential Building Code, eff. Oct 1, 2016). Applies only in jurisdictions that had no residential code before March 2010; those with an earlier local code may keep it.	Exempt if not over 4 ft measured from bottom of footing to top of wall, unless supporting a surcharge or impounding Class I, II or IIIA liquids (2015 IRC R105.2 as adopted; Alabama's amendments change only IRC Chapters 3, 11, 24 and 34).
Alaska	No statewide residential code (local adoption)	Set locally
Arizona	No statewide residential code (local adoption)	Set locally
Arkansas	2021 IRC as Arkansas Fire Prevention Code Vol. III (Residential), eff. Jan 1, 2023	No state-specific rule. The state's adopting rule amends parts of the code's permit chapter but lists no retaining wall change. Check with your city or county building department.
California	2025 California Residential Code (Title 24, Part 2.5), based on 2024 IRC, eff. Jan 1, 2026	Set locally. CRC Chapter 1 Division II (incl. R105.2) is not adopted by HCD except where indicated, so cities and counties adopt it, often with amendments. The CRC's R105.2 text exempts walls not over 4 ft from bottom of footing to top of wall, unless supporting a surcharge.
Colorado	No statewide residential code (local adoption). The 2024 IRC applies only to construction by state agencies (OSA Exhibit A, rev. 10/2026).	Set locally
Connecticut	2022 Connecticut State Building Code (2021 IRC portion with CT amendments), eff. Oct 1, 2022	Exempt if not higher than 3 ft (914 mm) measured from finished grade at the bottom of the wall to finished grade at the top, unless supporting a surcharge or impounding Class I, II or IIIA liquids (CT amendment to §105.2; towns apply the same 3 ft rule to homes under R105.2).
Delaware	No statewide residential code (local adoption)	Set locally
District of Columbia	2017 DC Construction Codes (built on the 2015 ICC model codes, incl. IRC, amended by 12 DCMR), eff. May 29, 2020	—
Florida	Florida Building Code, 8th Edition (2023), Residential volume, statewide, eff. Dec 31, 2023 (based on the 2021 IRC, according to FEMA)	No statewide height exemption: the Florida Building Code's permit-exemption list, as published by Miami-Dade and Lake County, doesn't include retaining walls. Since July 1, 2026 (HB 803, ch. 2026-63), a wall that spans several single-family, two-family or townhouse lots gets one permit for the whole project, and the new $7,500 single-family exemption doesn't apply to structural work.
Georgia	2024 IRC with Georgia amendments (mandatory state minimum standard), eff. Jan 1, 2026	Set locally. Georgia's IRC amendments delete Chapter 1 (incl. R105.2) and keep it only as a reference and guide for local governments; this amendment was carried forward for the 2024 code.
Hawaii	State Residential Code: 2018 IRC (as adopted by the State Building Code Council). The 2021 IRC was adopted by default without state amendments, but the counties enforce their own 2018-based codes.	Set locally (county building codes)
Idaho	Idaho Residential Code (2020 Edition) = 2018 IRC Parts I–III and IX with Idaho amendments. Local enforcement is optional, but jurisdictions that enforce must use the state code.	Exempt if not over 4 ft from bottom of footing to top of wall, unless supporting a surcharge or impounding Class I, II or IIIA liquids (2018 IRC R105.2 as adopted; Idaho amends only R105.2 items 7 (pools) and 11 (flag poles)).
Illinois	No statewide residential code. According to FEMA, jurisdictions that enforce a code must use an IRC edition published within the past 9 years. In areas without a building code, the new-home contract must adopt the IRC or a local code; the current IRC is the default (815 ILCS 670).	Set locally
Indiana	2020 Indiana Residential Code (2018 IRC with Indiana amendments, 675 IAC 14-4.4)	Set locally. Indiana deletes IRC R105 (incl. the R105.2 exemption list) and replaces it with an additions-and-alterations section.
Iowa	2024 IRC in the Iowa State Building Code (481 IAC 301.8, ARC 9474C, eff. Sept 10, 2025). Applies only to buildings covered by the state code under Iowa Code ch. 103A; according to FEMA, that means state-owned or state-financed buildings and cities over 15,000 without an equivalent local code.	Set locally. Iowa's adoption deletes IRC sections R103–R114 (incl. R105.2).
Kansas	No statewide residential code (local adoption)	Set locally
Kentucky	2018 Kentucky Residential Code, 3rd Ed. (Aug 2024), based on 2015 IRC (815 KAR 7:125, eff. Dec 3, 2024)	Set locally. The state regulation says permits, inspections and certificates of occupancy are not required for a single-family dwelling unless a local ordinance requires them (815 KAR 7:125 §2(2)(a)).
Louisiana	2021 IRC as amended by the Louisiana State Uniform Construction Code Council, eff. Jan 1, 2023	Set locally. Louisiana adopts the 2021 IRC 'not including Parts I-Administrative' (LAC 17:I.107), so the IRC's R105.2 permit exemptions aren't part of the state code.
Maine	2021 IRC with Maine amendments (MUBEC). The amended adoption has been enforced since Apr 7, 2025; enforcement is mandatory in municipalities of 4,000+ and optional below that.	Exempt if not over 4 ft (1219 mm) in height measured from finish grade to the top of the wall, unless supporting a surcharge (Maine replacement of IRC R105.2 item 3, 16-642 CMR ch. 5). Municipalities may add exemptions by ordinance.
Maryland	2021 IRC through the Maryland Building Performance Standards. Local jurisdictions may modify it with wide discretion (according to FEMA).	Model rule by default: exempt if not over 4 ft from bottom of footing to top of wall, unless supporting a surcharge or impounding Class I, II or IIIA liquids (2021 IRC R105.2 as incorporated by COMAR 09.12.51.04, which makes no change to R105). Counties and cities may change it by local amendment, and local amendments prevail (COMAR 09.12.51.05).
Massachusetts	780 CMR 10th Edition, Ch. 51 Massachusetts Residential Code (2021 IRC with MA amendments). First effective Oct 11, 2024; the only code in effect since the concurrency period ended June 30, 2025.	Exempt if not over 4 ft (1,219 mm) measured from the bottom of the footing to the top of the wall, unless supporting a surcharge (780 CMR 51.00 R105.2 item 3, 10th Edition).
Michigan	Michigan Residential Code based on 2021 IRC, eff. Aug 29, 2025 (replaced a code based on the 2015 IRC)	Exempt if not more than 4 ft from bottom of footing to top of wall, unless supporting a surcharge (Mich. Admin. Code R 408.30505, amending IRC R105.2). This is the wording from the code in effect until Aug. 29, 2025.
Minnesota	Minnesota Residential Code based on 2018 IRC (according to FEMA), part of the Minnesota State Building Code	Exempt if not over 4 ft (1,219 mm) measured from the bottom of the footing to the top of the wall, unless supporting a surcharge or impounding Class I, II or III-A liquids (Minn. R. 1300.0120, subp. 4.A.4).
Mississippi	According to FEMA, a statewide rule requires jurisdictions to adopt one of the three most recent IRC editions, and jurisdictions could opt out when the law passed. The International Code Council's adoption chart (Apr 2026) lists the 2024 IRC.	Set locally
Missouri	No statewide residential code (local adoption)	Set locally
Montana	2021 IRC (ARM 24.301.154; IRC Chs. 11–14 and 16–43 deleted; last amended eff. Sept 21, 2024)	Montana adopts the 2021 IRC (ARM 24.301.154) and lists no change to its permit exemptions. Confirm the 4 ft rule with your local building department or the state Building Codes Program.
Nebraska	2018 IRC as part of the state building code (Neb. Rev. Stat. 71-6403; excludes R313 and Chs. 25–33)	Set locally. Nebraska's state building code (2018 IRC) carries the model 4 ft R105.2 exemption, but counties, cities and villages administer their own codes and may amend permit and inspection provisions (Neb. Rev. Stat. 71-6406). There is no state permit program for homes.
Nevada	No statewide residential code (local adoption). The state's 2024 IRC adoption applies only to state-owned projects.	Set locally
New Hampshire	2021 IRC as part of the NH State Building Code (RSA 155-A:1, IV), eff. July 1, 2024 (HB 1059 of 2024)	Set locally. The state code applies statewide, but building permits exist only where a town or city has adopted local enforcement; that municipality decides.
New Jersey	2024 IRC (New Jersey edition) under the NJ Uniform Construction Code (N.J.A.C. 5:23-3.21), eff. Aug 17, 2026; applications may use the previous (2021) codes through Feb 17, 2027	A permit is required for any retaining wall with a total height of 4 ft or more, and for shorter walls that have a negative impact on a foundation. Total height is the sum of all walls on the same slope, measured from bottom of footing to top of wall (N.J.A.C. 5:23-2.14(g)). Walls dedicated to the municipality, bonded under the MLUL, or reviewed by a county engineer or NJDOT are excluded.
New Mexico	2021 New Mexico Residential Building Code (2021 IRC, 14.7.3 NMAC), eff. July 14, 2023; applies to work on or after Dec 14, 2023	Exempt if the wall retains less than 36 in (915 mm) of unbalanced fill and has a total height of 6 ft or less from top of wall to bottom of footing. Walls supporting a surcharge or impounding Class I, II or III-A liquids are not exempt (14.5.2.9(B) NMAC, modifying IRC R105.2(3)).
New York	2025 Residential Code of New York State (2025 Uniform Code), eff. Dec 31, 2025, with a transition period allowing the 2020 code. Based on the 2024 IRC, according to FEMA.	Not on the statewide exemption list. 19 NYCRR 1203.3's list of work exempt from building permits (small sheds, awnings, partitions, finish work, etc.) doesn't include retaining walls; local enforcement programs decide.
North Carolina	2018 NC Residential Code (2015 IRC basis) remains in effect. The 2024 NC Residential Code (2021 IRC basis) was adopted, but its effective date is delayed by legislation (according to FEMA, June 2025).	Set by your county or city inspections department. State law (G.S. 160D-1110(c)) waives permits for work of $40,000 or less in a single-family home unless it involves load-bearing structures or certain other work; it doesn't address retaining walls specifically.
North Dakota	2024 IRC in the North Dakota State Building Code, eff. Jan 1, 2026. Local enforcement is optional, but jurisdictions that enforce must use the state code and may amend it.	Set locally (optional local enforcement; local amendments allowed)
Ohio	Residential Code of Ohio (based on 2018 IRC, first printing); OAC 4101:8, Chapter 1 rule eff. July 1, 2019	Exempt if not over 4 ft (1219 mm) measured from the bottom of the footing to the top of the wall, unless supporting a surcharge (RCO §102.10, Building item 3).
Oklahoma	2024 IRC as the statewide minimum code (OAC 748:20-6), eff. Sept 14, 2026; previously the 2018 IRC	IRC R105.2 as adopted: exempt if not over 4 ft from bottom of footing to top of wall, unless surcharged or impounding Class I, II or IIIA liquids. The state adopts the code's permit chapter only where it doesn't conflict with state law or local enforcement authority.
Oregon	2026 Oregon Residential Specialty Code (2024 IRC basis), eff. Oct 1, 2026 (Chapter 1 adopted by OAR 918-480-0005)	No fixed statewide height. Statewide, a permit is required for retaining walls that provide safeguards for building users, support a regulated building, or retain material that could impact a regulated building if not restrained. Cities and counties may require permits for other walls by ordinance, but not for walls 4 ft or less (bottom of footing to top of wall) unless they support an ascending slope steeper than 3:1 or a nonsoil surcharge; a higher local threshold is allowed (2026 ORSC R101.2.2 item 2).
Pennsylvania	2021 IRC with PA modifications under the Uniform Construction Code, eff. Jan 1, 2026 (L&I Triennial Update, Reg. #12-125 / IRRC #3455: approved Oct 16, 2025, published in the Pa. Bulletin Nov 8, 2025). It replaced the 2018 IRC adoption that took effect Feb 14, 2022.	Exempt if not over 4 ft measured from the lowest level of grade to the top of the wall, unless the wall supports a surcharge (34 Pa. Code §403.62(c)(2)).
Rhode Island	RISBC-2 Rhode Island State One and Two Family Dwelling Code (2021 IRC with RI amendments, 510-RICR-00-00-2); current version eff. Dec 1, 2025	Exempt if not over 32 in high measured from the lower finished grade to the top of the wall, unless supporting a surcharge. Any cast-in-place concrete retaining wall over 24 in requires a permit (RISBC-2 R105.2 item 3, 510-RICR-00-00-2).
South Carolina	2021 IRC with SC modifications, eff. Jan 1, 2023. The 2024 SC Building Codes take effect Jan 1, 2027.	Exempt if not over 4 ft from bottom of footing to top of wall, unless supporting a surcharge or impounding Class I, II or IIIA liquids (2021 IRC R105.2 as adopted; the Council's 2021 modification index has no Chapter 1 changes).
South Dakota	No statewide residential code. According to FEMA, jurisdictions that adopt one must use the 2021 IRC.	Set locally
Tennessee	2018 IRC with Tennessee amendments (Rule 0780-02-23-.02), eff. July 16, 2020, adopted by the State Fire Marshal. According to FEMA, jurisdictions may opt out if they enforce a code no more than 7 years older than the latest edition.	Set locally. The state's residential program requires state permits only for new one- and two-family dwellings and townhouses and for additions of 30 sq ft or more of interior space (Rule 0780-02-23-.05); retaining walls aren't covered. Cities and counties that enforce their own codes decide.
Texas	No code for the whole state. According to FEMA, the 2012 IRC is the residential code for municipalities, which may amend it broadly.	Set locally
Utah	2021 IRC with Utah amendments (Utah Code Title 15A). HB 65 (2026) keeps the 2021 IRC while moving other codes to 2024.	Exempt if retaining less than 4 ft (1219 mm) of unbalanced fill, unless supporting a surcharge or requiring design per IRC R404.4 (HB 65 (2026) replacement of R105.2 item 3 in §15A-3-202, eff. July 1, 2026).
Vermont	No statewide residential code (local adoption)	Set locally
Virginia	2021 Virginia Uniform Statewide Building Code (2021 IRC basis), eff. Jan 18, 2024	Exempt if supporting less than 3 ft of unbalanced fill and not built to impound Class I, II or III-A liquids or to support a surcharge other than ordinary unbalanced fill (USBC §108.2, item 7; 13VAC5-63-80).
Washington	2021 IRC with WA amendments (State Building Code), eff. Mar 15, 2024. The 2024 IRC is targeted for adoption Oct 16, 2026, effective May 3, 2027.	Exempt if not over 4 ft from bottom of footing to top of wall, unless supporting a surcharge or impounding Class I, II or IIIA liquids (2021 IRC R105.2; WA's 2021 IRC amendment insert pages contain no R105.2 change).
West Virginia	2018 IRC in the WV State Building Code (87CSR4). It applies only where a city or county adopts the State Building Code.	Exempt if not over 4 ft from bottom of footing to top of wall, unless supporting a surcharge or impounding Class I, II or IIIA liquids (2018 IRC R105.2 as adopted; 87CSR4 amendments don't touch Chapter 1), in jurisdictions that adopt the code.
Wisconsin	Uniform Dwelling Code (Wis. Admin. Code SPS 320–325), Wisconsin's own code, not the IRC (according to FEMA)	Set locally. The Uniform Dwelling Code covers new one- and two-family dwellings and doesn't regulate retaining walls; municipalities may regulate structures outside its scope (detached buildings, fences, driveways and the like) by local ordinance (SPS 320.02(2)(c), per DSPS's UDC commentary).
Wyoming	No statewide residential code (local adoption)	Set locally

State-by-state details

Before you build any wall

Permit or not, a wall still has to stand up. Most wall failures come from water and poor compaction, not from the block. Plan the base, drainage stone and outlets first; our guides to retaining wall drainage, base depth and segmental wall systems cover the details, and the retaining wall block calculator sizes the order.

Frequently Asked Questions

How tall can a retaining wall be without a permit?

Under the model International Residential Code, 4 feet measured from the bottom of the footing to the top of the wall, as long as it doesn’t support a surcharge. Many states and towns follow that, but some measure differently or set a lower limit. Check your state above and your local building department.

Do I need an engineer for a retaining wall?

Usually once a wall is over the permit height or supports a surcharge like a driveway or slope. Wall block manufacturers also call for an engineered design above certain heights, especially with geogrid.

Does a terraced wall count as one wall or two?

It depends on the spacing. Walls stacked close together act like one taller wall, and building departments may treat them that way. Ask before you build terraces.

What happens if I build a retaining wall without a permit?

If one was required, the town can order you to stop, get a permit after the fact, open it up for inspection or remove it. It can also come up when you sell the house.

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Last checked October 31, 2026 against official state and local sources for all 51 entries. Rules change; your state agency or local building department has the final word. Spot something out of date? Email info@muthlerlandscaping.com and we’ll fix it.