Exceptions are provided for the following cases:

• One single-family residence, not exceeding two stories, when not constructed in conjunction with two or more residences by a single contractor or owner on a single parcel or abutting parcels, unless the site is located in an area subject to liquefaction or landslide.
• Any agricultural use not involving a building, and any agricultural accessory structure.
• Alterations or additions to any structure, the value of which does not exceed 50 percent of the assessed value of the structure, except where the site is adjacent to a coastal bluff. Engineered grading (quantities over 5,000 cubic yards, slope of 20% or greater, or within a GSA or flood hazard area) require engineering geology and geotechnical reports as required by sections 22.05.030 of the San Luis Obispo County Inland Land Use Ordinance and 23.05.030 of the San Luis Obispo County Coastal Land Use Ordinance.

As defined in sections 22.14.070 of the San Luis Obispo County Inland Land Use Ordinance and 23.07.080 of the San Luis Obispo County Coastal Zone Land Use Ordinance, GSAs include these hazards:

• Seismic: areas of fault rupture as defined by the State of California under the Alquist-Priolo Earthquake Fault Zone Act (sections 2621 et seq. of the Public Resources Code).
• Landslide: areas within urban and village reserve lines, identified by the San Luis Obispo County Safety Element as being subject to moderately high to high landslide risk; and rural areas subject to high landslide risk.
• Liquefaction: Areas identified by the San Luis Obispo County Safety Element as being subject to liquefaction.
• Erosion: areas along the coast with bluffs and cliffs greater than 10 feet in vertical relief and that are identified in the “Assessment and atlas of shoreline erosion” (Habel and Armstrong, 1977) as being critical to future or present development.