diff --git a/src/EnergyPlus/HeatBalanceInternalHeatGains.cc b/src/EnergyPlus/HeatBalanceInternalHeatGains.cc
index 54c196713a6..20070569e6d 100644
--- a/src/EnergyPlus/HeatBalanceInternalHeatGains.cc
+++ b/src/EnergyPlus/HeatBalanceInternalHeatGains.cc
@@ -154,6 +154,15 @@ void SetupSpaceInternalGain(EnergyPlusData &state,
 
     thisIntGain.device(thisIntGain.numberOfDevices).CompObjectName = UpperCaseObjectName;
     thisIntGain.device(thisIntGain.numberOfDevices).CompType = IntGainCompType;
+
+    // Tank losses should be distributed across multiplied zones/spaces - adjust the space gain fraction to account for this
+    if (std::find(AdjustTankLossMultipliers.begin(), AdjustTankLossMultipliers.end(), IntGainCompType) != AdjustTankLossMultipliers.end()) {
+        const int zoneNum = state.dataHeatBal->space(spaceNum).zoneNum;
+        const int multiplier = state.dataHeatBal->Zone(zoneNum).Multiplier * state.dataHeatBal->Zone(zoneNum).ListMultiplier;
+        if (multiplier > 1) {
+            spaceGainFraction /= multiplier;
+        }
+    }
     thisIntGain.device(thisIntGain.numberOfDevices).spaceGainFrac = spaceGainFraction;
 
     // note pointer assignments in code below!
diff --git a/src/EnergyPlus/HeatBalanceInternalHeatGains.hh b/src/EnergyPlus/HeatBalanceInternalHeatGains.hh
index eeafc2ff5c3..ea2dab8c1d4 100644
--- a/src/EnergyPlus/HeatBalanceInternalHeatGains.hh
+++ b/src/EnergyPlus/HeatBalanceInternalHeatGains.hh
@@ -83,6 +83,13 @@ void SetupSpaceInternalGain(EnergyPlusData &state,
                             int RetNodeNum = 0 // for return air heat gains
 );
 
+// Tank losses should be distributed across multiplied zones/spaces - these are the internal gains that need adjust for this
+static constexpr std::array<DataHeatBalance::IntGainType, 4> AdjustTankLossMultipliers = {
+    DataHeatBalance::IntGainType::WaterHeaterMixed,
+    DataHeatBalance::IntGainType::WaterHeaterStratified,
+    DataHeatBalance::IntGainType::ThermalStorageChilledWaterMixed,
+    DataHeatBalance::IntGainType::ThermalStorageChilledWaterStratified};
+
 struct HeatBalInternalHeatGainsData : BaseGlobalStruct
 {
 
diff --git a/tst/EnergyPlus/unit/WaterThermalTanks.unit.cc b/tst/EnergyPlus/unit/WaterThermalTanks.unit.cc
index db18cbebb3b..5013815ca80 100644
--- a/tst/EnergyPlus/unit/WaterThermalTanks.unit.cc
+++ b/tst/EnergyPlus/unit/WaterThermalTanks.unit.cc
@@ -6721,6 +6721,43 @@ TEST_F(EnergyPlusFixture, MixedTank_PVT_Per_VolumeSizing_PerSolarCollectorArea)
     EXPECT_DOUBLE_EQ(0.0, Tank.AmbientZoneGain); // Didn't define on/off cycle losses
 }
 
+TEST_F(EnergyPlusFixture, WaterThermalTankData_AdjustTankLossMultipliers)
+{
+    constexpr int ZONES = 1;
+    constexpr int SPACES = 5;
+    constexpr int FLOOR_AREA = 1000;
+    constexpr int MULTIPLIER = 10;
+
+    state->dataHeatBal->Zone.allocate(ZONES);
+    state->dataHeatBal->Zone(ZONES).numSpaces = SPACES;
+    state->dataHeatBal->Zone(ZONES).FloorArea = FLOOR_AREA;
+    state->dataHeatBal->Zone(ZONES).ListMultiplier = MULTIPLIER;
+    state->dataHeatBal->Zone(ZONES).Multiplier = MULTIPLIER;
+    state->dataHeatBal->Zone(ZONES).spaceIndexes.allocate(SPACES);
+
+    state->dataHeatBal->space.allocate(SPACES);
+    state->dataHeatBal->spaceIntGainDevices.allocate(SPACES);
+
+    for (int spaceNum = 1; spaceNum <= SPACES; spaceNum++) {
+        state->dataHeatBal->Zone(ZONES).spaceIndexes(spaceNum) = spaceNum;
+        state->dataHeatBal->space(spaceNum).FloorArea = static_cast<Real64>(FLOOR_AREA) / SPACES;
+        state->dataHeatBal->space(spaceNum).zoneNum = ZONES;
+    }
+
+    WaterThermalTanks::WaterThermalTankData tank;
+    tank.Name = "Water Heater";
+    tank.WaterThermalTankType = DataPlant::PlantEquipmentType::WtrHeaterMixed;
+    tank.AmbientTempZone = ZONES;
+    tank.setupZoneInternalGains(*state);
+
+    Real64 spaceGainFracTotal(0);
+    for (int spaceNum = 1; spaceNum <= SPACES; spaceNum++) {
+        spaceGainFracTotal += state->dataHeatBal->spaceIntGainDevices(spaceNum).device(1).spaceGainFrac * state->dataHeatBal->Zone(ZONES).Multiplier *
+                              state->dataHeatBal->Zone(ZONES).ListMultiplier;
+    }
+    EXPECT_NEAR(spaceGainFracTotal, 1, 0.001);
+}
+
 TEST_F(EnergyPlusFixture, thermalStorageTankInputReading_Autocalculate)
 {
     // Test for #11282