Hillside Building Regulations
In addition to the standard building regulations that exist in the California Building Code, there are other regulations for grading and building in the hillside areas of the City of Irvine to help make those areas safe.

Within the hillside areas exist numerous hazards associated with debris flow, slope instability, rock fall and erosion. The purpose of the hillside regulations is to identify which areas of the hillside are safe to build and which should be left as open space.

The following are some of the requirements that affect hillside construction: All hillside developments must be investigated from a geotechnical/geologic viewpoint to identify any potential instability or hazards. 

In general, graded slopes can be no steeper than 2:1 (horizontal:vertical) or 26 degrees. Structures must be located a specified distance (set back) from the top or toe of a slope, depending on the height and steepness of the slope. In hillside areas, roads can locally be as steep as 12 percent and driveways should not be steeper than 15 percent. 

Building in a hillside area also requires additional engineering for footings, foundations and retaining walls, which may be necessary to assure stability. Meeting requirements of hillside ordinances often means spending money for engineering and construction that would not be necessary for a flatland lot.  

For more information about hillside grading and construction, visit the City of Irvine, Community Development Department located at 1 Civic Center Plaza, from 7:30 a.m.-5:30 p.m. Monday-Thursday, and from 8 a.m.-5 p.m. Friday. 

For additional questions, contact Tom Polson, Engineering Geologist, at 949-724-6367.