In 2014 there were 1,598 private households in Sempach with an average household size of 2.58persons. Of the 635 inhabited buildings in the municipality, in 2000, about 58.0% were single family homes and 18.3% were multiple family buildings. Additionally, about 14.0% of the buildings were built before 1919, while 21.4% were built between 1991 and 2000. In 2013 the rate of construction of new housing units per 1000 residents was 5.78. The vacancy rate for the municipality, , was 0.64%. there were 615 inhabited buildings in the municipality, of which 474 were built only as housing, and 141 were mixed use buildings. There were 358 single family homes, 44 double family homes, and 72 multi-family homes in the municipality. Most homes were either two (248) or three (163) story structures. There were only 16 single story buildings and 47 four or more story buildings.