Sprinklers requirements for one and two family dwellings were included in the International Residential Code (IRC) by consensus vote but have been struck down by many states adopting the IRC, including Hawaii.  The opposition comes mainly from home builder associations.  The writer states the cost to be in "the tens of thousands of dollars". The standard....NFPA 13D.  It is nowhere as inclusive as the standards (NFPA 13) for a high rise.  13D systems can be run off the domestic water supply without all the alarms and monitoring of the NFPA 13 standard.  Arguments can be made that it should be the owners choice but "Tens of thousands of dollars". I think not.