La. R.S. 50:173.1. Vertical control standards

Vertical controls for all surveys shall be determined in the North American Vertical Datum of 1988 (NAVD88). All measurements shall be referenced to local control stations of the National Spatial Reference System, specifically the public domain Louisiana State University Continuously Operating Reference Stations network or other currently National Oceanographic and Atmospheric Administration National Geodetic Survey approved reference stations, such as benchmarks, monuments, or continually operating reference stations.

https://legis.la.gov/Legis/Law.aspx?d=410843