Terrebonne Parish, LA Accessory Structures: ADU Rules (2026)

Terrebonne Parish's zoning ordinance, Chapter 28 of the parish code, defines an accessory dwelling unit at Sec. ' The definition doubles as the operative permitting standard: accessory dwelling units are a permitted use in single-family residential districts within the zoned areas of Terrebonne Parish (the Houma area), subject to two conditions written directly into the code. First, the property owner must occupy either the main dwelling or the accessory unit as a primary residence, so the arrangement cannot be run as two separate rentals with an absentee owner.

Second, the accessory unit's gross floor area cannot exceed the gross square footage of the main dwelling unit, which caps a garage apartment or guesthouse at roughly the size of the primary home. The code lists garage apartments, guesthouses and pool or game houses as examples covered by the definition. Because an ADU is also an accessory structure, it must meet the supplementary yard rules at Sec. 28-74(e): it cannot sit closer than five feet to a side or rear property line, cannot occupy any part of a required front or side yard, and in residential districts cannot cover more than thirty percent of the required rear yard.

Sec. 28-73(d) further caps any accessory structure's height at no more than the height of the main structure on the lot. Outside the zoned areas of Terrebonne Parish, this district-based permitted-use language does not apply, since those areas fall under Chapter 29 Land Use rather than Chapter 28 Zoning.