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

50-1, Authorized Land Uses for Mixed-Use Base Zoning Districts, carries the row for LBCS 1121, described as "Secondary or accessory dwelling unit," with a "P" (permitted by right, per Sec. 2(b)(1)) in only the U-1S and U-1R columns, and an "X" in OBM-1, OBM-2, TCMU, and all three FC subdistricts. 40-1, prohibits the use outright ("X") across all five industrial base districts: I-MU, I-L, I-H, I-LF, and AIM. A "P" designation is not always the last word in U-1S: under Sec. 3(a)(1)(a), a "P" use there is reclassified as a special permitted use (SPU) requiring Jefferson Parish Council approval under Sec.

23 if it falls within any trigger listed in Sec. 3(a)(2), including single-, two-, three-, or four-family development exceeding ten lots or two acres, or a residential use sited less than 3,000 feet from the NOLA Motorsports main track as it existed when Ordinance 25020 was adopted October 7, 2015. In the U-1R district, Sec. 1 describes land "where it has been determined that development will be restricted due to the natural topography of the area," and Sec. 2(a) requires a Parish Infrastructure and Environmental Review (PIER) certificate under Sec.

39-10 for any use sited on the unprotected side of the Pontchartrain and Vicinity Hurricane Protection Levee, the West Bank and Vicinity Hurricane Protection Levee, the Mississippi River and Tributaries Flood Protection Levee, or beyond the parish's Urban Growth Limit Line. Notably, Sec. 10, the Residential Zoning Districts Use Matrix that would cover standard districts such as S-1, R-1A, R-1B, R-2, RR-3, and R-3, is marked "(reserved)" in the current UDC text, so those districts are still zoned under the legacy Chapter 40 ordinance rather than under a UDC accessory-dwelling standard.