A method to control a laundry washing machine having—an outer casing, a washing tub; a rotatable drum; a water softening device provided with ion exchanger agents designed to reduce the hardness degree of fresh water to be used during said washing program; a brine tank which is designed to supply, during a regeneration cycle, a prefixed amount of the brine to the water softening device for regenerating the ion exchanger agents; perform a waste-brine cleaning cycle for washing-out the waste brine solution contained in the water softening device and/or in the brine tank. The method controls the washing machine according to a washing program comprising one or more a washing phases, one or more rinse phases and one or more spin phases; and performs the regeneration cycle and the waste-brine cleaning cycle during respective washing program phases, which are different one to the other.