ADU laws in Louisiana

In plain words

Louisiana has no state law about ADUs. An ADU, or accessory dwelling unit, is a small second home on the same lot as a house. It might be a backyard cottage, a garage apartment, or a suite inside the house. In Louisiana, each city or parish decides through its zoning. Zoning is the local rulebook for what can be built where. Many rural parishes have little zoning at all. We found no ADU bill in the Legislature's records from 2023 through 2026. A 2026 state law changes how manufactured and modular homes are licensed and inspected starting in 2027. It does not say whether ADUs are allowed. The three biggest cities take different paths. New Orleans has no ADU category in its zoning code. Baton Rouge allows one ADU in many residential zones, but only with a conditional use permit. That is a case-by-case approval that can be granted or denied, not an automatic one. Lafayette's code allows one accessory apartment per lot in its farm and residential zones, with no hearing if it meets the written standards. It can be up to 800 square feet, or a quarter of the house's size if that is bigger. It may be rented. Even where zoning allows an ADU, other rules still apply. Building codes and flood rules may affect the design. HOA rules and deed restrictions can ban a second unit. If you use a septic system, ask the health department what approval you need. Before you plan, call your city or parish planning office. You may be able to build only if local rules and your property allow it.

The rules at a glance

What to do next

1. Find out whether your property is inside a city or in unincorporated parish land, and which government's zoning applies.
2. Look up your zoning district and read the code for terms such as 'accessory dwelling', 'accessory apartment' or 'garage apartment'.
3. Ask the planning office whether an ADU needs only a building permit or a hearing, such as Baton Rouge's conditional use permit.
4. Check flood zone rules and elevation requirements for your lot before you design.
5. Contact the parish health unit early if the property uses a septic system or well.
6. Read your deed and any HOA covenants, then get every zoning approval and building permit before construction starts.

What your town still decides

Louisiana has no statute that requires or protects ADUs. Under R.S. 33:4721, a municipality may regulate building height and size, lot coverage, yards, population density and the use of land; parishes and consolidated city-parish governments (such as Baton Rouge-East Baton Rouge and Lafayette) adopt their own development codes. Each one decides whether a second home may go on a lot, and many rural parishes have little or no zoning. A 2022 House bill (HB 737), which would have let owners act as their own contractor when building an ADU, died in committee. The Legislature's own full-text bill search finds no ADU bill using 'accessory dwelling', 'accessory apartment', 'accessory unit', 'secondary dwelling', 'tiny home' or 'granny' in any regular session from 2023 through 2026 or in the 2024 and 2025 extraordinary sessions. A 2026 law, Act 765 (SB 398, effective January 1, 2027), reorganizes state regulation of manufactured and modular homes under the contractors' licensing board and requires municipalities and parishes to inspect their installation; it does not address whether ADUs are allowed. The three largest cities differ: New Orleans' zoning ordinance has no ADU category, Baton Rouge-East Baton Rouge requires a conditional use permit, and Lafayette's development code allows one accessory apartment per lot by right in its agricultural, residential and several mixed-use districts.

Examples of local rules

• New Orleans: A full-text search of the city's online Comprehensive Zoning Ordinance on this date found no accessory dwelling unit use or standards. Secondary sources report that a 2021 City Council motion asked the City Planning Commission to recommend ADU rules, but no adopted ADU ordinance was found. Many lots are zoned for two-family dwellings, which is a separate use from an ADU. Source
• Baton Rouge-East Baton Rouge Parish: Under Unified Development Code Section 9.5.2.A (September 2025 edition), one accessory dwelling may be allowed on a lot with a single-family home in the A2, A2.7, A3.1, A3.2, A3.3, A4, A5, NO and NC zoning districts. It must sit in the rear yard at least 10 feet from the side and rear lot lines and outside required buffers. A conditional use permit is required for every accessory dwelling, which means a discretionary review rather than approval by right. Source
• Lafayette (city and unincorporated Lafayette Parish): The Lafayette Development Code (amended May 2026), § 89-74, allows one 'accessory apartment' per lot, located in or on the same lot as a single-family home. The use table lists it as allowed by right in the A, RS-1, RS-2, RM, MN, MX and D districts and as a conditional use in CM and CH. Its living area may be up to 800 sq ft or 25% of the main house's floor area, whichever is greater. It may be rented but not sold separately, must meet the main house's setbacks (with a 5-foot rear setback in RS and RM districts and unincorporated areas), and a new detached unit needs a building permit with a scaled site plan. Source

What we’re still confirming

• Confirm with Lafayette planning staff which districts allow accessory apartments and whether any owner-occupancy or parking rules apply.
• Whether New Orleans is drafting new ADU rules after a 2021 City Council request for a study isn't confirmed.

This is general information, not legal advice. Your town, village, city or county decides what can be built on your property. If something here looks out of date, email the team.