now please cite the Mass law that says the occupant may not increase the temperature.
the law specifies the max temperature a licensed individual may set.
if one opts to install an instant sink-side heater delivering 185'F water, there is no prohibition of the sale, installation, or use of such a device.
don't misunderstand my point - it is quite clear public policy/law is established to prevent people from becoming injured by overly hot water. there is however no law that prohibits a person from making their own hot water hotter than public law allows within their domicile.
the law only prohibits the owner/landlord to set the temperature of delivered hot water higher than xxx'F