diff --git a/src/ZB.MOM.WW.ScadaBridge.TemplateEngine/Services/InstanceService.cs b/src/ZB.MOM.WW.ScadaBridge.TemplateEngine/Services/InstanceService.cs
index 0e7ed342..0d4a497e 100644
--- a/src/ZB.MOM.WW.ScadaBridge.TemplateEngine/Services/InstanceService.cs
+++ b/src/ZB.MOM.WW.ScadaBridge.TemplateEngine/Services/InstanceService.cs
@@ -213,6 +213,7 @@ public class InstanceService
     /// <param name="triggerConfigurationOverride">Override JSON for the trigger configuration.</param>
     /// <param name="priorityLevelOverride">Override priority level, or null to use template value.</param>
     /// <param name="user">Username of the user setting the override.</param>
+    /// <param name="isMesReportableOverride">Override for the alarm's MES-reportable flag, or null to use the template value.</param>
     /// <param name="cancellationToken">Cancellation token.</param>
     /// <returns>Result containing the alarm override or failure message.</returns>
     public async Task<Result<InstanceAlarmOverride>> SetAlarmOverrideAsync(
@@ -221,6 +222,7 @@ public class InstanceService
         string? triggerConfigurationOverride,
         int? priorityLevelOverride,
         string user,
+        bool? isMesReportableOverride = null,
         CancellationToken cancellationToken = default)
     {
         var instance = await _repository.GetInstanceByIdAsync(instanceId, cancellationToken);
@@ -254,6 +256,7 @@ public class InstanceService
         {
             existingOverride.TriggerConfigurationOverride = triggerConfigurationOverride;
             existingOverride.PriorityLevelOverride = priorityLevelOverride;
+            existingOverride.IsMesReportableOverride = isMesReportableOverride;
             await _repository.UpdateInstanceAlarmOverrideAsync(existingOverride, cancellationToken);
             await _repository.SaveChangesAsync(cancellationToken);
 
@@ -268,7 +271,8 @@ public class InstanceService
             {
                 InstanceId = instanceId,
                 TriggerConfigurationOverride = triggerConfigurationOverride,
-                PriorityLevelOverride = priorityLevelOverride
+                PriorityLevelOverride = priorityLevelOverride,
+                IsMesReportableOverride = isMesReportableOverride
             };
 
             await _repository.AddInstanceAlarmOverrideAsync(newOverride, cancellationToken);
diff --git a/src/ZB.MOM.WW.ScadaBridge.TemplateEngine/TemplateService.cs b/src/ZB.MOM.WW.ScadaBridge.TemplateEngine/TemplateService.cs
index c524a344..e559ab45 100644
--- a/src/ZB.MOM.WW.ScadaBridge.TemplateEngine/TemplateService.cs
+++ b/src/ZB.MOM.WW.ScadaBridge.TemplateEngine/TemplateService.cs
@@ -621,6 +621,7 @@ public class TemplateService
         existing.Description = proposed.Description;
         existing.OnTriggerScriptId = proposed.OnTriggerScriptId;
         existing.IsLocked = proposed.IsLocked;
+        existing.IsMesReportable = proposed.IsMesReportable;
         if (template?.IsDerived == true)
             existing.IsInherited = proposed.IsInherited;
         else
diff --git a/tests/ZB.MOM.WW.ScadaBridge.TemplateEngine.Tests/Services/InstanceServiceTests.cs b/tests/ZB.MOM.WW.ScadaBridge.TemplateEngine.Tests/Services/InstanceServiceTests.cs
index b7e0a7fc..ae38bade 100644
--- a/tests/ZB.MOM.WW.ScadaBridge.TemplateEngine.Tests/Services/InstanceServiceTests.cs
+++ b/tests/ZB.MOM.WW.ScadaBridge.TemplateEngine.Tests/Services/InstanceServiceTests.cs
@@ -220,6 +220,101 @@ public class InstanceServiceTests
         Assert.Contains("locked", result.Error, StringComparison.OrdinalIgnoreCase);
     }
 
+    [Fact]
+    public async Task SetAlarmOverrideAsync_StoresIsMesReportableOverride()
+    {
+        var instance = new Instance("Inst1") { Id = 1, TemplateId = 1 };
+        _repoMock.Setup(r => r.GetInstanceByIdAsync(1, It.IsAny<CancellationToken>()))
+            .ReturnsAsync(instance);
+        _repoMock.Setup(r => r.GetAllTemplatesAsync(It.IsAny<CancellationToken>()))
+            .ReturnsAsync(new List<Template>
+            {
+                TemplateWithAlarms(1, new TemplateAlarm("HighTemp") { Id = 10, IsLocked = false })
+            });
+        _repoMock.Setup(r => r.GetAlarmOverrideAsync(1, "HighTemp", It.IsAny<CancellationToken>()))
+            .ReturnsAsync((InstanceAlarmOverride?)null);
+        _repoMock.Setup(r => r.SaveChangesAsync(It.IsAny<CancellationToken>()))
+            .ReturnsAsync(1);
+
+        InstanceAlarmOverride? added = null;
+        _repoMock.Setup(r => r.AddInstanceAlarmOverrideAsync(
+                It.IsAny<InstanceAlarmOverride>(), It.IsAny<CancellationToken>()))
+            .Callback<InstanceAlarmOverride, CancellationToken>((o, _) => added = o);
+
+        var result = await _sut.SetAlarmOverrideAsync(
+            1, "HighTemp", "{}", null, "admin", isMesReportableOverride: true);
+
+        Assert.True(result.IsSuccess);
+        Assert.NotNull(added);
+        Assert.True(added!.IsMesReportableOverride);
+        Assert.True(result.Value.IsMesReportableOverride);
+    }
+
+    [Fact]
+    public async Task SetAlarmOverrideAsync_NullIsMesReportableOverride_ClearsExistingOverride()
+    {
+        var instance = new Instance("Inst1") { Id = 1, TemplateId = 1 };
+        _repoMock.Setup(r => r.GetInstanceByIdAsync(1, It.IsAny<CancellationToken>()))
+            .ReturnsAsync(instance);
+        _repoMock.Setup(r => r.GetAllTemplatesAsync(It.IsAny<CancellationToken>()))
+            .ReturnsAsync(new List<Template>
+            {
+                TemplateWithAlarms(1, new TemplateAlarm("HighTemp") { Id = 10, IsLocked = false })
+            });
+
+        var existingOverride = new InstanceAlarmOverride("HighTemp")
+        {
+            Id = 5,
+            InstanceId = 1,
+            IsMesReportableOverride = true
+        };
+        _repoMock.Setup(r => r.GetAlarmOverrideAsync(1, "HighTemp", It.IsAny<CancellationToken>()))
+            .ReturnsAsync(existingOverride);
+        _repoMock.Setup(r => r.SaveChangesAsync(It.IsAny<CancellationToken>()))
+            .ReturnsAsync(1);
+
+        var result = await _sut.SetAlarmOverrideAsync(
+            1, "HighTemp", "{}", null, "admin", isMesReportableOverride: null);
+
+        Assert.True(result.IsSuccess);
+        Assert.Null(existingOverride.IsMesReportableOverride);
+        Assert.Null(result.Value.IsMesReportableOverride);
+        _repoMock.Verify(r => r.UpdateInstanceAlarmOverrideAsync(
+            It.Is<InstanceAlarmOverride>(o => o.IsMesReportableOverride == null),
+            It.IsAny<CancellationToken>()), Times.Once);
+    }
+
+    [Fact]
+    public async Task SetAlarmOverrideAsync_UpdatesIsMesReportableOverrideOnExisting()
+    {
+        var instance = new Instance("Inst1") { Id = 1, TemplateId = 1 };
+        _repoMock.Setup(r => r.GetInstanceByIdAsync(1, It.IsAny<CancellationToken>()))
+            .ReturnsAsync(instance);
+        _repoMock.Setup(r => r.GetAllTemplatesAsync(It.IsAny<CancellationToken>()))
+            .ReturnsAsync(new List<Template>
+            {
+                TemplateWithAlarms(1, new TemplateAlarm("HighTemp") { Id = 10, IsLocked = false })
+            });
+
+        var existingOverride = new InstanceAlarmOverride("HighTemp")
+        {
+            Id = 5,
+            InstanceId = 1,
+            IsMesReportableOverride = null
+        };
+        _repoMock.Setup(r => r.GetAlarmOverrideAsync(1, "HighTemp", It.IsAny<CancellationToken>()))
+            .ReturnsAsync(existingOverride);
+        _repoMock.Setup(r => r.SaveChangesAsync(It.IsAny<CancellationToken>()))
+            .ReturnsAsync(1);
+
+        var result = await _sut.SetAlarmOverrideAsync(
+            1, "HighTemp", "{}", 3, "admin", isMesReportableOverride: false);
+
+        Assert.True(result.IsSuccess);
+        Assert.False(existingOverride.IsMesReportableOverride);
+        Assert.Equal(3, existingOverride.PriorityLevelOverride);
+    }
+
     [Fact]
     public async Task Enable_ExistingInstance_SetsEnabled()
     {
diff --git a/tests/ZB.MOM.WW.ScadaBridge.TemplateEngine.Tests/TemplateServiceTests.cs b/tests/ZB.MOM.WW.ScadaBridge.TemplateEngine.Tests/TemplateServiceTests.cs
index 7c7adc1f..e00ac6a3 100644
--- a/tests/ZB.MOM.WW.ScadaBridge.TemplateEngine.Tests/TemplateServiceTests.cs
+++ b/tests/ZB.MOM.WW.ScadaBridge.TemplateEngine.Tests/TemplateServiceTests.cs
@@ -530,6 +530,65 @@ public class TemplateServiceTests
         Assert.Contains("TriggerType", result.Error);
     }
 
+    [Fact]
+    public async Task UpdateAlarmAsync_CopiesIsMesReportable()
+    {
+        var existing = new TemplateAlarm("HighTemp")
+        {
+            Id = 1,
+            TemplateId = 1,
+            TriggerType = AlarmTriggerType.ValueMatch,
+            PriorityLevel = 500,
+            IsMesReportable = false
+        };
+        _repoMock.Setup(r => r.GetTemplateAlarmByIdAsync(1, It.IsAny<CancellationToken>())).ReturnsAsync(existing);
+
+        var template = new Template("Pump") { Id = 1 };
+        _repoMock.Setup(r => r.GetTemplateByIdAsync(1, It.IsAny<CancellationToken>())).ReturnsAsync(template);
+
+        var proposed = new TemplateAlarm("HighTemp")
+        {
+            TriggerType = AlarmTriggerType.ValueMatch,
+            PriorityLevel = 500,
+            IsMesReportable = true
+        };
+        var result = await _service.UpdateAlarmAsync(1, proposed, "admin");
+
+        Assert.True(result.IsSuccess);
+        Assert.True(result.Value.IsMesReportable);
+        Assert.True(existing.IsMesReportable);
+        _repoMock.Verify(r => r.UpdateTemplateAlarmAsync(
+            It.Is<TemplateAlarm>(a => a.IsMesReportable), It.IsAny<CancellationToken>()), Times.Once);
+    }
+
+    [Fact]
+    public async Task UpdateAlarmAsync_ClearsIsMesReportable()
+    {
+        var existing = new TemplateAlarm("HighTemp")
+        {
+            Id = 1,
+            TemplateId = 1,
+            TriggerType = AlarmTriggerType.ValueMatch,
+            PriorityLevel = 500,
+            IsMesReportable = true
+        };
+        _repoMock.Setup(r => r.GetTemplateAlarmByIdAsync(1, It.IsAny<CancellationToken>())).ReturnsAsync(existing);
+
+        var template = new Template("Pump") { Id = 1 };
+        _repoMock.Setup(r => r.GetTemplateByIdAsync(1, It.IsAny<CancellationToken>())).ReturnsAsync(template);
+
+        var proposed = new TemplateAlarm("HighTemp")
+        {
+            TriggerType = AlarmTriggerType.ValueMatch,
+            PriorityLevel = 500,
+            IsMesReportable = false
+        };
+        var result = await _service.UpdateAlarmAsync(1, proposed, "admin");
+
+        Assert.True(result.IsSuccess);
+        Assert.False(result.Value.IsMesReportable);
+    }
+
     // ========================================================================
     // WP-4: Script Definitions
     // ========================================================================