diff --git a/Data.SeaHavenIndustries/Migrations/20260813193000_SH121_BoardSearchFacets.cs b/Data.SeaHavenIndustries/Migrations/20260813193000_SH121_BoardSearchFacets.cs
new file mode 100644
index 0000000..3405792
--- /dev/null
+++ b/Data.SeaHavenIndustries/Migrations/20260813193000_SH121_BoardSearchFacets.cs
@@ -0,0 +1,25 @@
+using Microsoft.EntityFrameworkCore.Migrations;
+
+#nullable disable
+
+namespace Data.SeaHavenIndustries.Migrations
+{
+    /// <inheritdoc />
+    /// <summary>
+    /// SH-121 originally added <c>IsAddOn</c> for search facets. Column + legacy backfill
+    /// now live in <c>20260730150000_WoIsAddOn</c> (SH-184). This migration is a no-op so
+    /// both PRs can land without a duplicate column.
+    /// </summary>
+    public partial class SH121_BoardSearchFacets : Migration
+    {
+        /// <inheritdoc />
+        protected override void Up(MigrationBuilder migrationBuilder)
+        {
+        }
+
+        /// <inheritdoc />
+        protected override void Down(MigrationBuilder migrationBuilder)
+        {
+        }
+    }
+}
diff --git a/Data.SeaHavenIndustries/Models/WorkerOrder.cs b/Data.SeaHavenIndustries/Models/WorkerOrder.cs
index 3ce4cc9..b2d1989 100644
--- a/Data.SeaHavenIndustries/Models/WorkerOrder.cs
+++ b/Data.SeaHavenIndustries/Models/WorkerOrder.cs
@@ -80,7 +80,7 @@ namespace Data.SeaHavenIndustries
         // --- Analytics slice ---
         public int RescheduleCount { get; set; }
         public int CarriedOver { get; set; }
-        /// <summary>Recalculated on schedule set/change/clear (SH-184); create hint when unscheduled.</summary>
+        /// <summary>Recalculated on schedule set/change/clear (SH-184); create hint when unscheduled. Board/search facet.</summary>
         public bool IsAddOn { get; set; }
         public OperationalFlags OperationalFlags { get; set; }
 
diff --git a/SeaHaven.DataServices/Helpers/WorkOrderBoardSearchFacetFilters.cs b/SeaHaven.DataServices/Helpers/WorkOrderBoardSearchFacetFilters.cs
new file mode 100644
index 0000000..08b2c2d
--- /dev/null
+++ b/SeaHaven.DataServices/Helpers/WorkOrderBoardSearchFacetFilters.cs
@@ -0,0 +1,166 @@
+using Data.SeaHavenIndustries;
+using Data.SeaHavenIndustries.Enums;
+using Microsoft.EntityFrameworkCore;
+
+namespace SeaHaven.DataServices.Helpers
+{
+    /// <summary>
+    /// SH-121/SH-196 advanced search facets (severity, indicators, flag, internal WO#, uplift).
+    /// </summary>
+    public static class WorkOrderBoardSearchFacetFilters
+    {
+        private static readonly WorkOrderType[] SeverityEligibleTypes =
+        {
+            WorkOrderType.Emergency,
+            WorkOrderType.Reactive,
+        };
+
+        private static readonly string[] RevokedUpliftStatuses =
+        {
+            "Withdrawn",
+            "Cancelled",
+        };
+
+        public static IQueryable<WorkOrder> ApplySeverityFilter(
+            IQueryable<WorkOrder> query,
+            IReadOnlyList<int>? severities)
+        {
+            if (severities == null || severities.Count == 0)
+                return query;
+
+            var allowed = severities
+                .Where(s => s is >= 1 and <= 5)
+                .Select(s => s.ToString())
+                .Distinct()
+                .ToList();
+
+            if (allowed.Count == 0)
+                return query;
+
+            return query.Where(w =>
+                w.WorkOrderType != null
+                && SeverityEligibleTypes.Contains(w.WorkOrderType.Value)
+                && w.Severity != null
+                && allowed.Contains(w.Severity));
+        }
+
+        public static IQueryable<WorkOrder> ApplyRescheduledFilter(
+            IQueryable<WorkOrder> query,
+            bool rescheduled)
+        {
+            if (!rescheduled)
+                return query;
+
+            return query.Where(w => w.RescheduleCount >= 2);
+        }
+
+        public static IQueryable<WorkOrder> ApplyCarriedOverFilter(
+            IQueryable<WorkOrder> query,
+            bool carriedOver)
+        {
+            if (!carriedOver)
+                return query;
+
+            return query.Where(w => w.CarriedOver >= 2);
+        }
+
+        public static IQueryable<WorkOrder> ApplyAddOnFilter(
+            IQueryable<WorkOrder> query,
+            bool addOn)
+        {
+            if (!addOn)
+                return query;
+
+            return query.Where(w => w.IsAddOn);
+        }
+
+        public static IQueryable<WorkOrder> ApplyFlagColorFilter(
+            IQueryable<WorkOrder> query,
+            IReadOnlyList<string>? flagColors)
+        {
+            if (flagColors == null || flagColors.Count == 0)
+                return query;
+
+            var normalized = flagColors
+                .Where(c => !string.IsNullOrWhiteSpace(c))
+                .Select(c => c.Trim().ToUpperInvariant())
+                .Distinct()
+                .ToList();
+
+            if (normalized.Count == 0)
+                return query;
+
+            return query.Where(w =>
+                w.FlagColor != null && normalized.Contains(w.FlagColor.ToUpper()));
+        }
+
+        public static IQueryable<WorkOrder> ApplyInternalOnlyFilter(
+            IQueryable<WorkOrder> query,
+            bool internalOnly)
+        {
+            if (!internalOnly)
+                return query;
+
+            return query.Where(w =>
+                w.InternalWONumber != null
+                && EF.Functions.Like(w.InternalWONumber, "SH%"));
+        }
+
+        public static IQueryable<WorkOrder> ApplyUpliftFilter(
+            IQueryable<WorkOrder> query,
+            ApplicationDbContext context,
+            bool hasUplift,
+            IReadOnlyList<string>? upliftStatuses)
+        {
+            if (!hasUplift)
+                return query;
+
+            var mappedStatuses = MapUpliftStatuses(upliftStatuses);
+
+            return query.Where(w => context.DispatchUpliftRequests.Any(u =>
+                (u.IsDeleted == null || u.IsDeleted == false)
+                && u.Status != "Expired"
+                && !RevokedUpliftStatuses.Contains(u.Status)
+                && u.Dispatch != null
+                && (u.Dispatch.IsDeleted == null || u.Dispatch.IsDeleted == false)
+                && (
+                    u.Dispatch.WorkOrderId == w.Id
+                    || u.Dispatch.DispatchWorkOrders!.Any(link => link.WorkOrderId == w.Id))
+                && (mappedStatuses.Count == 0 || mappedStatuses.Contains(u.Status))));
+        }
+
+        internal static List<string> MapUpliftStatuses(IReadOnlyList<string>? upliftStatuses)
+        {
+            if (upliftStatuses == null || upliftStatuses.Count == 0)
+                return new List<string>();
+
+            var mapped = new List<string>();
+            foreach (var raw in upliftStatuses)
+            {
+                if (string.IsNullOrWhiteSpace(raw))
+                    continue;
+
+                switch (raw.Trim().ToLowerInvariant())
+                {
+                    case "pending":
+                        mapped.Add("Pending");
+                        mapped.Add("ChangesRequested");
+                        break;
+                    case "approved":
+                        mapped.Add("Approved");
+                        break;
+                    case "auto_approved":
+                        mapped.Add("NoApprovalRequired");
+                        break;
+                    case "rejected":
+                        mapped.Add("Rejected");
+                        mapped.Add("Denied");
+                        break;
+                }
+            }
+
+            return mapped.Distinct(StringComparer.Ordinal).ToList();
+        }
+    }
+
+}
diff --git a/SeaHaven.DataServices/Implementation/WorkOrderAdvancedSearchDataService.cs b/SeaHaven.DataServices/Implementation/WorkOrderAdvancedSearchDataService.cs
index de1f4d2..1d4892d 100644
--- a/SeaHaven.DataServices/Implementation/WorkOrderAdvancedSearchDataService.cs
+++ b/SeaHaven.DataServices/Implementation/WorkOrderAdvancedSearchDataService.cs
@@ -28,6 +28,14 @@ namespace SeaHaven.DataServices.Implementation
             baseQuery = WorkOrderBoardQueryFilters.ApplyPmTypeFilter(baseQuery, query.PmTypes);
             baseQuery = WorkOrderBoardQueryFilters.ApplyVendorFilter(baseQuery, query.VendorIds);
             baseQuery = WorkOrderBoardQueryFilters.ApplyDocStatusFilter(baseQuery, query.DocStatuses);
+            baseQuery = WorkOrderBoardSearchFacetFilters.ApplySeverityFilter(baseQuery, query.Severities);
+            baseQuery = WorkOrderBoardSearchFacetFilters.ApplyRescheduledFilter(baseQuery, query.Rescheduled);
+            baseQuery = WorkOrderBoardSearchFacetFilters.ApplyCarriedOverFilter(baseQuery, query.CarriedOver);
+            baseQuery = WorkOrderBoardSearchFacetFilters.ApplyAddOnFilter(baseQuery, query.AddOn);
+            baseQuery = WorkOrderBoardSearchFacetFilters.ApplyFlagColorFilter(baseQuery, query.FlagColors);
+            baseQuery = WorkOrderBoardSearchFacetFilters.ApplyInternalOnlyFilter(baseQuery, query.InternalOnly);
+            baseQuery = WorkOrderBoardSearchFacetFilters.ApplyUpliftFilter(
+                baseQuery, _context, query.HasUplift, query.UpliftStatuses);
 
             var normalizedSearch = WorkOrderBoardSearchFilter.NormalizeSearch(query.Search);
             if (normalizedSearch != null)
diff --git a/SeaHaven.DataServices/Interfaces/WorkOrderAdvancedSearchModels.cs b/SeaHaven.DataServices/Interfaces/WorkOrderAdvancedSearchModels.cs
index d1ef77f..b965e86 100644
--- a/SeaHaven.DataServices/Interfaces/WorkOrderAdvancedSearchModels.cs
+++ b/SeaHaven.DataServices/Interfaces/WorkOrderAdvancedSearchModels.cs
@@ -15,6 +15,14 @@ namespace SeaHaven.DataServices.Interfaces
         IReadOnlyList<string>? PmTypes,
         IReadOnlyList<int>? VendorIds,
         IReadOnlyList<DocStatus>? DocStatuses,
+        IReadOnlyList<int>? Severities,
+        bool Rescheduled,
+        bool CarriedOver,
+        bool AddOn,
+        IReadOnlyList<string>? FlagColors,
+        bool InternalOnly,
+        bool HasUplift,
+        IReadOnlyList<string>? UpliftStatuses,
         bool MyWorkOrders,
         string? CurrentUserId,
         int Page,
diff --git a/SeaHaven.Services/DTOs/WorkOrderBoardRequestDTOs.cs b/SeaHaven.Services/DTOs/WorkOrderBoardRequestDTOs.cs
index 5f1bbb9..0f7d976 100644
--- a/SeaHaven.Services/DTOs/WorkOrderBoardRequestDTOs.cs
+++ b/SeaHaven.Services/DTOs/WorkOrderBoardRequestDTOs.cs
@@ -68,6 +68,14 @@ namespace SeaHaven.Services.DTOs
         public List<string>? PmTypes { get; set; }
         public List<int>? VendorIds { get; set; }
         public List<DocStatus>? DocStatuses { get; set; }
+        public List<int>? Severities { get; set; }
+        public bool Rescheduled { get; set; }
+        public bool CarriedOver { get; set; }
+        public bool AddOn { get; set; }
+        public List<string>? FlagColors { get; set; }
+        public bool InternalOnly { get; set; }
+        public bool HasUplift { get; set; }
+        public List<string>? UpliftStatuses { get; set; }
         public bool MyWorkOrders { get; set; }
         public string? SortBy { get; set; }
         public string? SortDir { get; set; }
diff --git a/SeaHaven.Services/Implementation/WorkOrderAdvancedSearchService.cs b/SeaHaven.Services/Implementation/WorkOrderAdvancedSearchService.cs
index a4d332d..f1e79cf 100644
--- a/SeaHaven.Services/Implementation/WorkOrderAdvancedSearchService.cs
+++ b/SeaHaven.Services/Implementation/WorkOrderAdvancedSearchService.cs
@@ -51,6 +51,14 @@ namespace SeaHaven.Services.Implementation
                 query.PmTypes,
                 query.VendorIds,
                 query.DocStatuses,
+                query.Severities,
+                query.Rescheduled,
+                query.CarriedOver,
+                query.AddOn,
+                query.FlagColors,
+                query.InternalOnly,
+                query.HasUplift,
+                query.UpliftStatuses,
                 query.MyWorkOrders,
                 currentUserId,
                 page,
diff --git a/SeaHavenIndustries.Tests/WorkOrderBoardSearchTests.cs b/SeaHavenIndustries.Tests/WorkOrderBoardSearchTests.cs
index 79b6f7c..04aa6c0 100644
--- a/SeaHavenIndustries.Tests/WorkOrderBoardSearchTests.cs
+++ b/SeaHavenIndustries.Tests/WorkOrderBoardSearchTests.cs
@@ -669,4 +669,164 @@ public class WorkOrderAdvancedSearchServiceTests
         Assert.Contains(result.Items, i => i.Id == 2 && i.IsAddOn && i.WorkOrderType == WorkOrderType.PM);
         Assert.DoesNotContain(result.Items, i => i.Id == 3);
     }
+
+    [Fact]
+    public async Task SearchAsync_SeverityFilter_ReturnsEmergencyReactiveOnly()
+    {
+        await using var context = CreateContext();
+        var weekStart = new DateOnly(2026, 6, 22);
+
+        context.workOrders.AddRange(
+            new WorkOrder
+            {
+                Id = 1,
+                WorkOrderType = WorkOrderType.Emergency,
+                Severity = "1",
+                ScheduledDate = new DateTime(2026, 6, 23),
+                LifecycleStatus = LifecycleStatus.Scheduled,
+                InternalWONumber = "10000000001",
+            },
+            new WorkOrder
+            {
+                Id = 2,
+                WorkOrderType = WorkOrderType.Reactive,
+                Severity = "2",
+                ScheduledDate = new DateTime(2026, 6, 24),
+                LifecycleStatus = LifecycleStatus.Scheduled,
+                InternalWONumber = "10000000002",
+            },
+            new WorkOrder
+            {
+                Id = 3,
+                WorkOrderType = WorkOrderType.PM,
+                Severity = "1",
+                ScheduledDate = new DateTime(2026, 6, 25),
+                LifecycleStatus = LifecycleStatus.Scheduled,
+                InternalWONumber = "10000000003",
+            });
+
+        await context.SaveChangesAsync();
+
+        var dataService = new WorkOrderAdvancedSearchDataService(context);
+        var service = new SeaHaven.Services.Implementation.WorkOrderAdvancedSearchService(
+            dataService,
+            WorkOrderAccountTestHelpers.Resolver(context));
+
+        var result = await service.SearchAsync(
+            new SeaHaven.Services.DTOs.WorkOrderAdvancedSearchQueryDto
+            {
+                DatePreset = SeaHaven.Services.Helpers.WorkOrderAdvancedSearchDatePreset.Custom,
+                DateFrom = weekStart,
+                DateTo = weekStart.AddDays(6),
+                Severities = new List<int> { 1 },
+            },
+            WorkOrderAccountTestHelpers.OrgWideAdmin(),
+            null);
+
+        Assert.Equal(1, result.TotalCount);
+        Assert.Equal(1, result.Items.Single().Id);
+    }
+
+    [Fact]
+    public async Task SearchAsync_InternalOnly_ReturnsShPrefixRows()
+    {
+        await using var context = CreateContext();
+        var weekStart = new DateOnly(2026, 6, 22);
+
+        context.workOrders.AddRange(
+            new WorkOrder
+            {
+                Id = 1,
+                InternalWONumber = "SH-1001",
+                ScheduledDate = new DateTime(2026, 6, 23),
+                LifecycleStatus = LifecycleStatus.Scheduled,
+            },
+            new WorkOrder
+            {
+                Id = 2,
+                InternalWONumber = "10000000002",
+                ScheduledDate = new DateTime(2026, 6, 24),
+                LifecycleStatus = LifecycleStatus.Scheduled,
+            });
+
+        await context.SaveChangesAsync();
+
+        var dataService = new WorkOrderAdvancedSearchDataService(context);
+        var service = new SeaHaven.Services.Implementation.WorkOrderAdvancedSearchService(
+            dataService,
+            WorkOrderAccountTestHelpers.Resolver(context));
+
+        var result = await service.SearchAsync(
+            new SeaHaven.Services.DTOs.WorkOrderAdvancedSearchQueryDto
+            {
+                DatePreset = SeaHaven.Services.Helpers.WorkOrderAdvancedSearchDatePreset.Custom,
+                DateFrom = weekStart,
+                DateTo = weekStart.AddDays(6),
+                InternalOnly = true,
+            },
+            WorkOrderAccountTestHelpers.OrgWideAdmin(),
+            null);
+
+        Assert.Equal(1, result.TotalCount);
+        Assert.Equal("SH-1001", result.Items.Single().WoNumber);
+    }
+
+    [Fact]
+    public async Task SearchAsync_HasUpliftWithPendingStatus_FiltersRows()
+    {
+        await using var context = CreateContext();
+        var weekStart = new DateOnly(2026, 6, 22);
+
+        context.Vendors.Add(new Vendor { Id = 1, CompanyName = "Acme HVAC" });
+        context.Dispatches.Add(new Dispatch { Id = 10, VendorId = 1, WorkOrderId = 1 });
+        context.Dispatches.Add(new Dispatch { Id = 11, VendorId = 1, WorkOrderId = 2 });
+        context.workOrders.AddRange(
+            new WorkOrder
+            {
+                Id = 1,
+                InternalWONumber = "10000000001",
+                ScheduledDate = new DateTime(2026, 6, 23),
+                LifecycleStatus = LifecycleStatus.Scheduled,
+                PrimaryDispatchId = 10,
+            },
+            new WorkOrder
+            {
+                Id = 2,
+                InternalWONumber = "10000000002",
+                ScheduledDate = new DateTime(2026, 6, 24),
+                LifecycleStatus = LifecycleStatus.Scheduled,
+                PrimaryDispatchId = 11,
+            });
+        context.DispatchUpliftRequests.Add(new DispatchUpliftRequest
+        {
+            Id = 100,
+            DispatchId = 10,
+            RequestedNTE = 1500m,
+            Status = "Pending",
+            RequiredTier = 1,
+            NotificationStatus = "Pending",
+        });
+
+        await context.SaveChangesAsync();
+
+        var dataService = new WorkOrderAdvancedSearchDataService(context);
+        var service = new SeaHaven.Services.Implementation.WorkOrderAdvancedSearchService(
+            dataService,
+            WorkOrderAccountTestHelpers.Resolver(context));
+
+        var result = await service.SearchAsync(
+            new SeaHaven.Services.DTOs.WorkOrderAdvancedSearchQueryDto
+            {
+                DatePreset = SeaHaven.Services.Helpers.WorkOrderAdvancedSearchDatePreset.Custom,
+                DateFrom = weekStart,
+                DateTo = weekStart.AddDays(6),
+                HasUplift = true,
+                UpliftStatuses = new List<string> { "pending" },
+            },
+            WorkOrderAccountTestHelpers.OrgWideAdmin(),
+            null);
+
+        Assert.Equal(1, result.TotalCount);
+        Assert.Equal(1, result.Items.Single().Id);
+    }
 }