diff --git a/src/Ydb.Sdk/CHANGELOG.md b/src/Ydb.Sdk/CHANGELOG.md
index e6a04532..b5d5e014 100644
--- a/src/Ydb.Sdk/CHANGELOG.md
+++ b/src/Ydb.Sdk/CHANGELOG.md
@@ -1,6 +1,7 @@
+- Feat ADO.NET: Mark `YdbConnection.State` as `Broken` when the underlying session is broken, including background deactivation.
 - Feat ADO.NET: Added  YdbDataSource `ExecuteAsync` and `ExecuteInTransaction` convenience methods.
 - **Breaking Change**: moved and renamed `Ydb.Sdk.Services.Query.TxMode` -> `Ydb.Sdk.Ado.TransactionMode`.
-- Feat ADO.NET: cache gRPC transport by `gRPCConnectionString` to reuse channels.
+- Feat ADO.NET: Cache gRPC transport by `gRPCConnectionString` to reuse channels.
 - Fix bug wrap-around ADO.NET: Big parameterized Decimal — `((ulong)bits[1] << 32)` -> `((ulong)(uint)bits[1] << 32)`.
 - Feat ADO.NET: Parameterized Decimal overflow check: `Precision` and `Scale`.
 - Feat ADO.NET: Deleted support for `DateTimeOffset` was a mistake.
diff --git a/src/Ydb.Sdk/src/Ado/PoolManager.cs b/src/Ydb.Sdk/src/Ado/PoolManager.cs
index 1eae6b04..feb13ee5 100644
--- a/src/Ydb.Sdk/src/Ado/PoolManager.cs
+++ b/src/Ydb.Sdk/src/Ado/PoolManager.cs
@@ -50,7 +50,7 @@ CancellationToken cancellationToken
 
     internal static async Task ClearPool(string connectionString)
     {
-        if (Pools.Remove(connectionString, out var sessionPool))
+        if (Pools.TryRemove(connectionString, out var sessionPool))
         {
             try
             {
diff --git a/src/Ydb.Sdk/src/Ado/YdbConnection.cs b/src/Ydb.Sdk/src/Ado/YdbConnection.cs
index 848fc772..83a2a80e 100644
--- a/src/Ydb.Sdk/src/Ado/YdbConnection.cs
+++ b/src/Ydb.Sdk/src/Ado/YdbConnection.cs
@@ -102,30 +102,38 @@ public override async Task OpenAsync(CancellationToken cancellationToken)
 
     public override async Task CloseAsync()
     {
-        if (State == ConnectionState.Closed)
+        // ReSharper disable once SwitchStatementHandlesSomeKnownEnumValuesWithDefault
+        switch (State)
         {
-            return;
-        }
-
-        try
-        {
-            if (LastReader is { IsClosed: false })
-            {
-                await LastReader.CloseAsync();
-            }
-
-            if (CurrentTransaction is { Completed: false })
-            {
-                await CurrentTransaction.RollbackAsync();
-            }
-
-            OnStateChange(OpenToClosedEventArgs);
-
-            ConnectionState = ConnectionState.Closed;
-        }
-        finally
-        {
-            _session.Close();
+            case ConnectionState.Closed:
+                return;
+            case ConnectionState.Broken:
+                ConnectionState = ConnectionState.Closed;
+                _session.Close();
+                return;
+            default:
+                try
+                {
+                    if (LastReader is { IsClosed: false })
+                    {
+                        await LastReader.CloseAsync();
+                    }
+
+                    if (CurrentTransaction is { Completed: false })
+                    {
+                        await CurrentTransaction.RollbackAsync();
+                    }
+
+                    OnStateChange(OpenToClosedEventArgs);
+
+                    ConnectionState = ConnectionState.Closed;
+                }
+                finally
+                {
+                    _session.Close();
+                }
+
+                break;
         }
     }
 
@@ -145,19 +153,14 @@ public override string ConnectionString
 
     public override string Database => _connectionStringBuilder?.Database ?? string.Empty;
 
-    public override ConnectionState State => ConnectionState;
+    public override ConnectionState State =>
+        ConnectionState != ConnectionState.Closed && _session.IsBroken // maybe is updated asynchronously
+            ? ConnectionState.Broken
+            : ConnectionState;
 
     private ConnectionState ConnectionState { get; set; } = ConnectionState.Closed; // Invoke AsyncOpen()
 
-    internal void OnNotSuccessStatusCode(StatusCode code)
-    {
-        _session.OnNotSuccessStatusCode(code);
-
-        if (_session.IsBroken)
-        {
-            ConnectionState = ConnectionState.Broken;
-        }
-    }
+    internal void OnNotSuccessStatusCode(StatusCode code) => _session.OnNotSuccessStatusCode(code);
 
     internal YdbDataReader? LastReader { get; set; }
     internal string LastCommand { get; set; } = string.Empty;
@@ -203,7 +206,7 @@ public override Task<DataTable> GetSchemaAsync(
 
     internal void ThrowIfConnectionClosed()
     {
-        if (ConnectionState is ConnectionState.Closed or ConnectionState.Broken)
+        if (State is ConnectionState.Closed or ConnectionState.Broken)
         {
             throw new InvalidOperationException("Connection is closed");
         }
@@ -211,7 +214,7 @@ internal void ThrowIfConnectionClosed()
 
     private void ThrowIfConnectionOpen()
     {
-        if (ConnectionState == ConnectionState.Open)
+        if (State == ConnectionState.Open)
         {
             throw new InvalidOperationException("Connection already open");
         }
diff --git a/src/Ydb.Sdk/src/IDriver.cs b/src/Ydb.Sdk/src/IDriver.cs
index aaa6533e..c0a8c2ff 100644
--- a/src/Ydb.Sdk/src/IDriver.cs
+++ b/src/Ydb.Sdk/src/IDriver.cs
@@ -210,14 +210,14 @@ protected async ValueTask<CallOptions> GetCallOptions(GrpcRequestSettings settin
     }
 
     public ILoggerFactory LoggerFactory { get; }
-    public void RegisterOwner() => _ownerCount++;
+    public void RegisterOwner() => ++_ownerCount;
     public bool IsDisposed => Disposed == 1;
 
     public void Dispose() => DisposeAsync().AsTask().GetAwaiter().GetResult();
 
     public async ValueTask DisposeAsync()
     {
-        if (Interlocked.Decrement(ref _ownerCount) <= 0 && Interlocked.CompareExchange(ref Disposed, 1, 0) == 0)
+        if (--_ownerCount <= 0 && Interlocked.CompareExchange(ref Disposed, 1, 0) == 0)
         {
             await ChannelPool.DisposeAsync();
 
diff --git a/src/Ydb.Sdk/test/Ydb.Sdk.Ado.Tests/PoolManagerTests.cs b/src/Ydb.Sdk/test/Ydb.Sdk.Ado.Tests/PoolManagerTests.cs
index 562f3b04..c3c5c6a7 100644
--- a/src/Ydb.Sdk/test/Ydb.Sdk.Ado.Tests/PoolManagerTests.cs
+++ b/src/Ydb.Sdk/test/Ydb.Sdk.Ado.Tests/PoolManagerTests.cs
@@ -28,6 +28,8 @@ public class PoolManagerTests
     public async Task PoolManager_CachingAndCleanup(string[] connectionStrings, int expectedDrivers, int expectedPools)
     {
         await YdbConnection.ClearAllPools();
+        foreach (var (_, driver) in PoolManager.Drivers)
+            Assert.True(driver.IsDisposed);
         PoolManager.Drivers.Clear();
 
         var connections = connectionStrings
@@ -45,9 +47,7 @@ public async Task PoolManager_CachingAndCleanup(string[] connectionStrings, int
         await Task.WhenAll(parallelTasks);
 
         foreach (var (_, driver) in PoolManager.Drivers)
-        {
             Assert.False(driver.IsDisposed);
-        }
 
         Assert.Equal(expectedDrivers, PoolManager.Drivers.Count);
         Assert.Equal(expectedPools, PoolManager.Pools.Count);