For some 50 years, the Geotechnical Unit has compiled data on the soil, including data on about 280,000 individual drillings. Geotechnical analysis and groundwater data, soil maps, bedrock maps and constructability maps, cost data, and information on different foundation methods are available. Soil factors should be taken into account as one cost factor already when purchasing a plot, or no later than when a building is sited on the plot and the foundation method for the building studied.  In addition, information on how to take radon into consideration in construction is provided.