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

Section 17-2041, Secondary Family Residences, permits a secondary single-family residence on a single lot specifically for immediate family members of the property owner, and the code defines that family circle narrowly: children, grandchildren, parents and grandparents, so a secondary house for a sibling, cousin or unrelated tenant does not qualify under this provision. The occupancy is capped at whatever residential density the underlying zoning district already allows under Table B, meaning a Rural or Conservation lot cannot simply add a second dwelling without regard to lot size and density limits.

The single carved-out exception is for Conservation districts, where the code relaxes the normal one-unit-per-large-lot density specifically to allow one secondary single-family residence per half-acre, a meaningfully denser allowance than Conservation's base single-family standard. The section also preserves other Ascension Parish rules on family land partitions, so a family that instead subdivides a larger tract into separate lots for relatives is governed by the parish's family-partition regulations rather than this secondary-residence allowance. Because a secondary residence is still a residential structure, it must independently meet Table B's lot size, setback and height standards for its district and go through the standard development-permit and building-permit process under Section 17-2090 before construction.