Index: firmware/App/Modes/ModeDrain.c
===================================================================
diff -u -r2e3b3b2034ee5afb52a8630568145c9705afff9f -r78a138b18328bce8312abac79d76aad9dfe8ea3a
--- firmware/App/Modes/ModeDrain.c	(.../ModeDrain.c)	(revision 2e3b3b2034ee5afb52a8630568145c9705afff9f)
+++ firmware/App/Modes/ModeDrain.c	(.../ModeDrain.c)	(revision 78a138b18328bce8312abac79d76aad9dfe8ea3a)
@@ -34,7 +34,8 @@
 // ********** private definitions **********
 
 #define TARGET_DRAIN_PUMP_RPM           1800                                ///< Target drain pump speed (in RPM).
-#define DRAIN_WEIGHT_UNCHANGE_TIMEOUT    ( 2 * MS_PER_SECOND )              ///< Time period of unchanged weight during draining before timeout.
+#define DRAIN_WEIGHT_UNCHANGE_TIMEOUT   ( 2 * MS_PER_SECOND )               ///< Time period of unchanged weight during draining before timeout.
+#define DRAIN_EMPTY_TARE_WAIT           ( MS_PER_SECOND )                   ///< Time period to wait after drain complete and before taring load cells.
 
 #define TARGET_RO_PRESSURE_PSI          130                                 ///< Target pressure for RO pump.
 #define TARGET_RO_FLOW_RATE_L           0.3                                 ///< Target flow rate for RO pump.
@@ -44,11 +45,13 @@
 
 // ********** private data **********
 
-static DG_DRAIN_STATE_T drainState = DG_DRAIN_STATE_START;                  ///< Currently active drain state.
+static DG_DRAIN_STATE_T drainState;                                         ///< Currently active drain state.
+static U32 drainEmptyTareTimerCtr;                                          ///< Timer counter for delay between drain complete and load cell tare.
 
 // ********** private function prototypes **********
 
 static DG_DRAIN_STATE_T handleDrainState( void );
+static DG_DRAIN_STATE_T handleTareState( void );
 
 /*********************************************************************//**
  * @brief
@@ -60,6 +63,7 @@
 void initDrainMode( void )
 {
     drainState = DG_DRAIN_STATE_START;
+    drainEmptyTareTimerCtr = 0;
 }
 
 /*********************************************************************//**
@@ -121,6 +125,10 @@
             drainState = handleDrainState();
             break;
 
+        case DG_DRAIN_STATE_TARE:
+            drainState = handleTareState();
+            break;
+
         default:
             SET_ALARM_WITH_2_U32_DATA( ALARM_ID_DG_SOFTWARE_FAULT, SW_FAULT_ID_DRAIN_MODE_INVALID_EXEC_STATE, drainState )
             drainState = DG_DRAIN_STATE_START;
@@ -132,9 +140,10 @@
 
 /*********************************************************************//**
  * @brief
- * The handleDrainState function handles the drain state  of the drain mode state machine.
+ * The handleDrainState function handles the drain state of the drain mode
+ * state machine.
  * @details Inputs: none
- * @details Outputs: Drain out from reservoir
+ * @details Outputs: none
  * @return the next state
  *************************************************************************/
 static DG_DRAIN_STATE_T handleDrainState( void )
@@ -146,7 +155,6 @@
     if ( hasTargetDrainVolumeBeenReached( inactiveReservoir, DRAIN_WEIGHT_UNCHANGE_TIMEOUT ) )
     {
         setDrainPumpTargetRPM( 0 );
-        requestNewOperationMode( DG_MODE_CIRC );
 
 #ifndef V_2_SYSTEM
         if ( DG_RESERVOIR_1 == inactiveReservoir )
@@ -158,13 +166,45 @@
             setValveState( VRD2, VALVE_STATE_CLOSED );
         }
 #endif
+
+        if ( TRUE == isReservoirTarePending() )
+        {   // Tare reservoir load cells at empty if requested
+            result = DG_DRAIN_STATE_TARE;
+        }
+        else
+        {
+            requestNewOperationMode( DG_MODE_CIRC );
+        }
     }
 
     return result;
 }
 
 /*********************************************************************//**
  * @brief
+ * The handleTareState function handles the tare state of the drain mode
+ * state machine.
+ * @details Inputs: drainEmptyTareTimerCtr
+ * @details Outputs: drainEmptyTareTimerCtr
+ * @return the next state
+ *************************************************************************/
+static DG_DRAIN_STATE_T handleTareState( void )
+{
+    DG_DRAIN_STATE_T result = DG_DRAIN_STATE_TARE;
+    DG_RESERVOIR_ID_T inactiveReservoir = getInactiveReservoir();
+
+    if ( ++drainEmptyTareTimerCtr > DRAIN_EMPTY_TARE_WAIT )
+    {
+        drainEmptyTareTimerCtr = 0;
+        tareLoadCellsAtEmpty( inactiveReservoir );
+        requestNewOperationMode( DG_MODE_CIRC );
+    }
+
+    return result;
+}
+
+/*********************************************************************//**
+ * @brief
  * The getCurrentDrainState function returns the current state of the drain mode.
  * @details Inputs: drainState
  * @details Outputs: none
Index: firmware/App/Services/Reservoirs.c
===================================================================
diff -u -r847478dd75aac2edfe27df454ac5a644b6f30040 -r78a138b18328bce8312abac79d76aad9dfe8ea3a
--- firmware/App/Services/Reservoirs.c	(.../Reservoirs.c)	(revision 847478dd75aac2edfe27df454ac5a644b6f30040)
+++ firmware/App/Services/Reservoirs.c	(.../Reservoirs.c)	(revision 78a138b18328bce8312abac79d76aad9dfe8ea3a)
@@ -472,21 +472,47 @@
     if ( hasTimeOut || hasTargetReached )
     {
         result = TRUE;
+        // Reset for next drain
         reservoirLowestWeight[ reservoirId ] = MAX_RESERVOIR_WEIGHT;
-
-        if ( tareLoadCellRequest )
-        {
-            tareLoadCellRequest = FALSE;
-            tareLoadCell( associatedLoadCell[ reservoirId ] );
-            tareLoadCell( redundantLoadCell[ reservoirId ] );
-        }
     }
 
     return result;
 }
 
 /*********************************************************************//**
  * @brief
+ * The tareLoadCellsAtEmpty function tares the load cells for the inactive
+ * reservoir when ModeDrain empties it and tare request is pending.
+ * @details Inputs: tareLoadCellRequest
+ * @details Outputs: tareLoadCellRequest
+ * @param reservoirId ID of reservoir to tare
+ * @return none
+ *************************************************************************/
+void tareLoadCellsAtEmpty( DG_RESERVOIR_ID_T reservoirId )
+{
+    if ( TRUE == tareLoadCellRequest )
+    {
+        tareLoadCellRequest = FALSE;
+        tareLoadCell( associatedLoadCell[ reservoirId ] );
+        tareLoadCell( redundantLoadCell[ reservoirId ] );
+    }
+}
+
+/*********************************************************************//**
+ * @brief
+ * The isReservoirTarePending function determines whether a reservoir tare
+ * request is currently pending.
+ * @details Inputs: tareLoadCellRequest
+ * @details Outputs: none
+ * @return tareLoadCellRequest
+ *************************************************************************/
+BOOL isReservoirTarePending( void )
+{
+    return tareLoadCellRequest;
+}
+
+/*********************************************************************//**
+ * @brief
  * The getActiveReservoir function gets the active reservoir.
  * @details Inputs: activeReservoir
  * @details Outputs: none
Index: firmware/App/Services/Reservoirs.h
===================================================================
diff -u -rebbb1f85550a1f9b8f946655f7b2b63f76fbf67d -r78a138b18328bce8312abac79d76aad9dfe8ea3a
--- firmware/App/Services/Reservoirs.h	(.../Reservoirs.h)	(revision ebbb1f85550a1f9b8f946655f7b2b63f76fbf67d)
+++ firmware/App/Services/Reservoirs.h	(.../Reservoirs.h)	(revision 78a138b18328bce8312abac79d76aad9dfe8ea3a)
@@ -85,7 +85,9 @@
 F32 getReservoirWeight( DG_RESERVOIR_ID_T reservoirId );
 
 BOOL hasTargetFillVolumeBeenReached( DG_RESERVOIR_ID_T reservoirId );
-BOOL hasTargetDrainVolumeBeenReached( DG_RESERVOIR_ID_T reservoirId , U32 timeout );
+BOOL hasTargetDrainVolumeBeenReached( DG_RESERVOIR_ID_T reservoirId, U32 timeout );
+void tareLoadCellsAtEmpty( DG_RESERVOIR_ID_T reservoirId );
+BOOL isReservoirTarePending( void );
 
 BOOL testSetDGActiveReservoirOverride( DG_RESERVOIR_ID_T value );
 BOOL testResetDGActiveReservoirOverride( void );