text: fig2 illustrates a cross - sectional view of a watering system 32 , according to an embodiment of the present invention . the system 32 includes a basin 34 having a base 36 integrally formed with an upstanding circumferential wall 38 . a reservoir 40 is positioned over the basin 34 , and is configured to allow water to pass into an annular drinking trough 42 defined by the wall 38 and an interior island 44 of the basin 34 . as shown in fig1 , the island 44 is lower than upper edges of the wall 38 . accordingly , a fluid path 46 is defined from the interior of the reservoir 40 , over the island 44 , and into the drinking trough 42 . at least one heating element 48 is secured above or below the upper surface of the island 44 and directed toward the interior chamber 50 of the reservoir 50 . the heating element 48 is configured to heat water within the interior chamber 50 . the heating element 48 may be a disk - shaped heating element that covers , or is underneath , a top surface of the island 44 . the heating element 48 is electrically connected to a temperature sensor 52 . additionally , at least one heating element 54 is secured on or underneath the island 44 proximate the trough 42 . the heating element 54 is configured to heat water within the trough 42 . the heating element 54 may be an annular - shaped heating element that tracks an inner wall of the basin that defines an inner boundary of the trough 42 . the heating element 54 is electrically connected to a temperature sensor 56 . the sensor 56 is disposed proximate the inner wall of the island 44 . optionally , the sensor 56 may be located proximate the bottom surface of the trough 42 . it has been found that placement of the sensor 56 in these locations provides exceptional sensing response . the wattage of the heating element 54 may differ from that of the heating element 48 . thus , the system 32 may enable differential heating of water at different locations . that is , water within the trough 42 may be heated to a first temperature , while water within the reservoir 40 may be heated to a second temperature that differs from the first temperature . as shown , embodiments of the present invention provide a system 32 including two separate heating elements 48 and 54 . the heating element 48 provides heat to water within the interior chamber 50 of the reservoir 40 , while the heating element 54 provides heat to water within the trough 42 . each heating element 48 and 54 is independently controlled by a separate and distinct temperature sensor 52 and 56 , respectively . the heating element 48 may be electrically connected to the temperature sensor 52 through a switch 60 . similarly , the heating element 54 may be electrically connected to the temperature sensor 56 through a switch 62 . the switches 60 and 62 allow the temperature sensors 52 and 56 , respectively , to selectively activate and deactivate the heating elements 48 and 54 , respectively , based on set - points of the sensors 52 and 56 . each heating element 48 and 54 is independently controlled by its respective thermostat 52 and 56 and the switches 60 and 62 to form a heating circuit . the two separate and distinct heating circuits can be wired in parallel to a single power source ( not shown ). in certain embodiments , the sensors 52 , 56 , and switches 60 and 62 , respectively , combine to form bimetal thermostats that are used as control devices for each heating element 48 and 54 , respectively . in such a configuration , each thermostat is in thermal contact with the outer surfaces of the island 44 . for plastic basins , a metal insert or screw that passes through the basin 34 may be employed to increase the thermal conductivity between the reservoir water and the thermostat , if desired . the sensors 52 and 56 may be mechanical , such as bimetal thermostats , or electronic , such as thermistors . the switches 60 and 62 may be mechanical contacts , such as found in a thermostat , or a triac and / or a relay . additional heating elements with their own respective controlling devices may be added in parallel . for example , a small heating element may be desired to cover a tube leading from the reservoir to the drinking trough or to a detached drinking tough . the temperature sensors 52 and 56 and heating elements 48 and 54 may be affixed directly to the underside of the basin 34 ( such as an upwardly - indented portion that defines the island 44 ). alternatively , the sensors 52 and 56 and the heating elements 48 and 54 may be detachably secured to mounting brackets that attach to the basin 34 . the power supplied to the heating elements 48 and 54 may be alternating or direct current , and may be supplied through a single electrical cord leading to a power source , such that the heating circuits are wired in parallel . optionally , power to each heating circuit may be routed from separate and distinct power sources . optionally , a processing unit 64 may be positioned on or within the basin 34 . the processing unit 64 may be in electrical communication with the heating elements 48 and 54 and the sensors 52 and 56 . the processing unit 64 may be programmed to control operation of the heating elements 48 and 54 based on detected water temperatures . that is , the processing unit 64 may activate and deactivate the heating elements 48 and 54 based on temperature readings that are relayed to the processing unit 64 through the sensors 52 and 56 . in this embodiment , the sensors 52 and 56 may be thermometers that detect the temperature of water and / or surface temperatures of the basin 34 at the locations of the sensors 52 and 56 . fig3 illustrates a flow chart of a method of operating a watering device , according to an embodiment of the present invention . at 70 , temperature within a water reservoir is monitored , as described above . at 72 , a temperature sensing circuit determines whether the water within the reservoir is above a temperature set - point . if the temperature exceeds the set point , the heating element is not activated at 74 , and the process returns to 70 . if , however , the temperature is below the set - point , the heating element is activated at 76 to heat the water within the reservoir , and the process returns to 70 . additionally , at 78 , the temperature of the water within the drinking trough is monitored with a separate and distinct sensing circuit , which determines at 80 whether the water within the trough is above a temperature set - point . at 82 , if the temperature of the water within the trough is above the set - point , the separate and distinct trough water heating element is not activated , and the process returns to 78 . if , however , the trough water temperature is below the set - point , at 84 , the separate and distinct trough water heating element is activated , and the process returns to 78 . embodiments of the present invention may be used in conjunction with the systems and methods shown and described in u . s . application ser . no . 12 / 695 , 769 , filed jan . 28 , 2010 , entitled “ system and method for automatically deactivating a poultry watering device ,” assigned to allied precision industries inc ., which is hereby incorporated by reference in its entirety thus , embodiments of the present invention provide a system and method of efficiently heating water within a watering system . because separate and distinct heating circuits are used to heat water within the trough and the reservoir , each heating circuit may be configured to heat water within each location to an ideal temperature that does not waste electricity . while various spatial terms , such as upper , bottom , lower , mid , lateral , horizontal , vertical , and the like may be used to describe embodiments of the present invention , it is understood that such terms are merely used with respect to the orientations shown in the drawings . the orientations may be inverted , rotated , or otherwise changed , such that an upper portion is a lower portion , and vice versa , horizontal becomes vertical , and the like . while the invention has been described with reference to certain embodiments , it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted without departing from the scope of the invention . in addition , many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from its scope . therefore , it is intended that the invention not be limited to the particular embodiments disclosed , but that the invention will include all embodiments falling within the scope of the appended claims .