diff --git a/src/Service.Tests/UnitTests/HealthCheckUtilitiesUnitTests.cs b/src/Service.Tests/UnitTests/HealthCheckUtilitiesUnitTests.cs
new file mode 100644
index 0000000000..db9e2d9409
--- /dev/null
+++ b/src/Service.Tests/UnitTests/HealthCheckUtilitiesUnitTests.cs
@@ -0,0 +1,155 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
+#nullable enable
+
+using System;
+using Azure.DataApiBuilder.Config.ObjectModel;
+using Azure.DataApiBuilder.Service.HealthCheck;
+using Microsoft.Extensions.Logging;
+using Microsoft.VisualStudio.TestTools.UnitTesting;
+using Moq;
+
+namespace Azure.DataApiBuilder.Service.Tests.UnitTests
+{
+    /// <summary>
+    /// Unit tests for health check utility methods.
+    /// </summary>
+    [TestClass]
+    public class HealthCheckUtilitiesUnitTests
+    {
+        /// <summary>
+        /// Tests that connection strings are properly normalized for supported database types.
+        /// </summary>
+        [TestMethod]
+        [DataRow(
+            DatabaseType.PostgreSQL,
+            "Host=localhost;Port=5432;Database=testdb;Username=testuser;Password=XXXX",
+            "Host=localhost",
+            "Database=testdb",
+            DisplayName = "PostgreSQL connection string normalization")]
+        [DataRow(
+            DatabaseType.MSSQL,
+            "Server=localhost;Database=testdb;User Id=testuser;Password=XXXX",
+            "Data Source=localhost",
+            "Initial Catalog=testdb",
+            DisplayName = "MSSQL connection string normalization")]
+        [DataRow(
+            DatabaseType.DWSQL,
+            "Server=localhost;Database=testdb;User Id=testuser;Password=XXXX",
+            "Data Source=localhost",
+            "Initial Catalog=testdb",
+            DisplayName = "DWSQL connection string normalization")]
+        [DataRow(
+            DatabaseType.MySQL,
+            "Server=localhost;Port=3306;Database=testdb;Uid=testuser;Pwd=XXXX",
+            "Server=localhost",
+            "Database=testdb",
+            DisplayName = "MySQL connection string normalization")]
+        public void NormalizeConnectionString_SupportedDatabases_Success(
+            DatabaseType dbType,
+            string connectionString,
+            string expectedServerPart,
+            string expectedDatabasePart)
+        {
+            // Act
+            string result = HealthCheck.Utilities.NormalizeConnectionString(connectionString, dbType);
+
+            // Assert
+            Assert.IsNotNull(result);
+            Assert.IsTrue(result.Contains(expectedServerPart));
+            Assert.IsTrue(result.Contains(expectedDatabasePart));
+        }
+
+        /// <summary>
+        /// Tests that unsupported database types return the original connection string.
+        /// </summary>
+        [TestMethod]
+        public void NormalizeConnectionString_UnsupportedType_ReturnsOriginal()
+        {
+            // Arrange
+            string connectionString = "AccountEndpoint=https://test.documents.azure.com:443/;AccountKey=test";
+            DatabaseType dbType = DatabaseType.CosmosDB_NoSQL;
+
+            // Act
+            string result = HealthCheck.Utilities.NormalizeConnectionString(connectionString, dbType);
+
+            // Assert
+            Assert.AreEqual(connectionString, result);
+        }
+
+        /// <summary>
+        /// Tests that malformed connection strings are handled gracefully.
+        /// </summary>
+        [TestMethod]
+        [DataRow(DatabaseType.PostgreSQL, true, DisplayName = "PostgreSQL malformed string with logger")]
+        [DataRow(DatabaseType.MSSQL, true, DisplayName = "MSSQL malformed string with logger")]
+        [DataRow(DatabaseType.MySQL, false, DisplayName = "MySQL malformed string without logger")]
+        public void NormalizeConnectionString_MalformedString_ReturnsOriginal(
+            DatabaseType dbType,
+            bool useLogger)
+        {
+            // Arrange
+            string malformedConnectionString = "InvalidConnectionString;NoEquals";
+            Mock<ILogger>? mockLogger = useLogger ? new Mock<ILogger>() : null;
+
+            // Act
+            string result = HealthCheck.Utilities.NormalizeConnectionString(
+                malformedConnectionString,
+                dbType,
+                mockLogger?.Object);
+
+            // Assert
+            Assert.AreEqual(malformedConnectionString, result);
+            if (useLogger && mockLogger != null)
+            {
+                mockLogger.Verify(
+                    x => x.Log(
+                        LogLevel.Warning,
+                        It.IsAny<EventId>(),
+                        It.Is<It.IsAnyType>((v, t) => true),
+                        It.IsAny<Exception>(),
+                        It.Is<Func<It.IsAnyType, Exception?, string>>((v, t) => true)),
+                    Times.Once);
+            }
+        }
+
+        /// <summary>
+        /// Tests that PostgreSQL connection strings with lowercase keywords are normalized correctly.
+        /// This is the specific bug that was reported - lowercase 'host' was not supported.
+        /// </summary>
+        [TestMethod]
+        public void NormalizeConnectionString_PostgreSQL_LowercaseKeywords_Success()
+        {
+            // Arrange
+            string connectionString = "host=localhost;port=5432;database=mydb;username=myuser;password=XXXX";
+            DatabaseType dbType = DatabaseType.PostgreSQL;
+
+            // Act
+            string result = HealthCheck.Utilities.NormalizeConnectionString(connectionString, dbType);
+
+            // Assert
+            Assert.IsNotNull(result);
+            // NpgsqlConnectionStringBuilder should normalize lowercase keywords to proper format
+            Assert.IsTrue(result.Contains("Host=localhost") || result.Contains("host=localhost"));
+            Assert.IsTrue(result.Contains("Database=mydb") || result.Contains("database=mydb"));
+        }
+
+        /// <summary>
+        /// Tests that empty connection strings are handled gracefully.
+        /// </summary>
+        [TestMethod]
+        public void NormalizeConnectionString_EmptyString_ReturnsEmpty()
+        {
+            // Arrange
+            string connectionString = string.Empty;
+            DatabaseType dbType = DatabaseType.PostgreSQL;
+
+            // Act
+            string result = HealthCheck.Utilities.NormalizeConnectionString(connectionString, dbType);
+
+            // Assert
+            Assert.AreEqual(string.Empty, result);
+        }
+    }
+}
diff --git a/src/Service/HealthCheck/HealthCheckHelper.cs b/src/Service/HealthCheck/HealthCheckHelper.cs
index ab19756195..991e39983f 100644
--- a/src/Service/HealthCheck/HealthCheckHelper.cs
+++ b/src/Service/HealthCheck/HealthCheckHelper.cs
@@ -162,7 +162,7 @@ private async Task UpdateDataSourceHealthCheckResultsAsync(ComprehensiveHealthCh
             if (comprehensiveHealthCheckReport.Checks != null && runtimeConfig.DataSource.IsDatasourceHealthEnabled)
             {
                 string query = Utilities.GetDatSourceQuery(runtimeConfig.DataSource.DatabaseType);
-                (int, string?) response = await ExecuteDatasourceQueryCheckAsync(query, runtimeConfig.DataSource.ConnectionString, Utilities.GetDbProviderFactory(runtimeConfig.DataSource.DatabaseType));
+                (int, string?) response = await ExecuteDatasourceQueryCheckAsync(query, runtimeConfig.DataSource.ConnectionString, Utilities.GetDbProviderFactory(runtimeConfig.DataSource.DatabaseType), runtimeConfig.DataSource.DatabaseType);
                 bool isResponseTimeWithinThreshold = response.Item1 >= 0 && response.Item1 < runtimeConfig.DataSource.DatasourceThresholdMs;
 
                 // Add DataSource Health Check Results
@@ -182,14 +182,14 @@ private async Task UpdateDataSourceHealthCheckResultsAsync(ComprehensiveHealthCh
         }
 
         // Executes the DB Query and keeps track of the response time and error message.
-        private async Task<(int, string?)> ExecuteDatasourceQueryCheckAsync(string query, string connectionString, DbProviderFactory dbProviderFactory)
+        private async Task<(int, string?)> ExecuteDatasourceQueryCheckAsync(string query, string connectionString, DbProviderFactory dbProviderFactory, DatabaseType databaseType)
         {
             string? errorMessage = null;
             if (!string.IsNullOrEmpty(query) && !string.IsNullOrEmpty(connectionString))
             {
                 Stopwatch stopwatch = new();
                 stopwatch.Start();
-                errorMessage = await _httpUtility.ExecuteDbQueryAsync(query, connectionString, dbProviderFactory);
+                errorMessage = await _httpUtility.ExecuteDbQueryAsync(query, connectionString, dbProviderFactory, databaseType);
                 stopwatch.Stop();
                 return string.IsNullOrEmpty(errorMessage) ? ((int)stopwatch.ElapsedMilliseconds, errorMessage) : (HealthCheckConstants.ERROR_RESPONSE_TIME_MS, errorMessage);
             }
diff --git a/src/Service/HealthCheck/HttpUtilities.cs b/src/Service/HealthCheck/HttpUtilities.cs
index 9da596ae30..2a8d7b9f3e 100644
--- a/src/Service/HealthCheck/HttpUtilities.cs
+++ b/src/Service/HealthCheck/HttpUtilities.cs
@@ -49,7 +49,7 @@ public HttpUtilities(
         }
 
         // Executes the DB query by establishing a connection to the DB.
-        public async Task<string?> ExecuteDbQueryAsync(string query, string connectionString, DbProviderFactory providerFactory)
+        public async Task<string?> ExecuteDbQueryAsync(string query, string connectionString, DbProviderFactory providerFactory, DatabaseType databaseType)
         {
             string? errorMessage = null;
             // Execute the query on DB and return the response time.
@@ -65,7 +65,7 @@ public HttpUtilities(
             {
                 try
                 {
-                    connection.ConnectionString = connectionString;
+                    connection.ConnectionString = Utilities.NormalizeConnectionString(connectionString, databaseType, _logger);
                     using (DbCommand command = connection.CreateCommand())
                     {
                         command.CommandText = query;
diff --git a/src/Service/HealthCheck/Utilities.cs b/src/Service/HealthCheck/Utilities.cs
index 290410291e..888ffbca91 100644
--- a/src/Service/HealthCheck/Utilities.cs
+++ b/src/Service/HealthCheck/Utilities.cs
@@ -7,6 +7,8 @@
 using System.Text.Json;
 using Azure.DataApiBuilder.Config.ObjectModel;
 using Microsoft.Data.SqlClient;
+using Microsoft.Extensions.Logging;
+using MySqlConnector;
 using Npgsql;
 
 namespace Azure.DataApiBuilder.Service.HealthCheck
@@ -69,5 +71,32 @@ public static string CreateHttpRestQuery(string entityName, int first)
             // "EntityName?$first=4"
             return $"/{entityName}?$first={first}";
         }
+
+        public static string NormalizeConnectionString(string connectionString, DatabaseType dbType, ILogger? logger = null)
+        {
+            try
+            {
+                switch (dbType)
+                {
+                    case DatabaseType.PostgreSQL:
+                        return new NpgsqlConnectionStringBuilder(connectionString).ToString();
+                    case DatabaseType.MySQL:
+                        return new MySqlConnectionStringBuilder(connectionString).ToString();
+                    case DatabaseType.MSSQL:
+                    case DatabaseType.DWSQL:
+                        return new SqlConnectionStringBuilder(connectionString).ToString();
+                    default:
+                        return connectionString;
+                }
+            }
+            catch (Exception ex)
+            {
+                // Log the exception if a logger is provided
+                logger?.LogWarning(ex, "Failed to parse connection string for database type {DatabaseType}. Returning original connection string.", dbType);
+                // If the connection string cannot be parsed by the builder,
+                // return the original string to avoid failing the health check.
+                return connectionString;
+            }
+        }
     }
 }