The area surrounding Port Lincoln can be divided into three main physiographic regions, the aeolianite plain, the coastal plain, and the highlands. Soil types range from shallow, well-drained terra rossa overlying the aeolianite, to imperfectly drained duplex soils overlying the basement rocks of the highlands, and the alluvial sediments of the coastal plain. Reticulated groundwater supplies are expected to meet the demand of the Port Lincoln Water District for the next 30 to 40 years. The only potable supplies of underground water are obtained from the aeolianite aquifer. The main building foundation problems likely to be encountered are low density collapsing soils associated with soft and friable aeolianite; possible expansive soils occurring in areas subject to inundation or associated with creek alluvium; and seepage problems in hillslope excavations due to high water tables and inadequate drainage. Sufficient reserves of aggregate and construction sand exist in the area for the foreseeable future, with alternative sources of coarse sand located to the north-west of the township. Proximity to the Lincoln Fault suggests that appropriate construction code requirements for earthquake resistant buildings be adopted for larger buildings.