California Vehicle Code definition of
House car
CVC Section 362. A "house car" is a motor vehicle originally designed, or
permanently altered, and equipped for human habitation, or to which a
camper has been permanently attached. A motor vehicle to which a
camper has been temporarily attached is not a house car except that,
for the purposes of Division 11 (commencing with Section 21000) and
Division 12 (commencing with Section 24000), a motor vehicle equipped
with a camper having an axle that is designed to support a portion
of the weight of the camper unit shall be considered a three-axle
house car regardless of the method of attachment or manner of
registration. A house car shall not be deemed to be a motortruck.