The odd cooking method among undergraduates at St Andrews in Fife has now resulted in the offenders receiving an emailed warning from university officials.
More than 300 students who live in the £3000-a-year Albany Park accommodation have been told by Cecilia Galloway, deputy residential services manager: "The boiler in house is not designed to give hot water for this length of time and when used like this it will cause problems in the boiler system and cut out the supply of the heat and hot water to the house.
"If this is appropriate to you please refrain from this action in the future."
Chef Mark Greenaway, owner of a three AA rosette restaurant in Edinburgh, said: "Jasmine and basmati rice should only take around five to 10 minutes for the water to run clear of starch."
Running a tap for an hour wastes up to 360 litres of water.