diff -u b/core/lib/Drupal/Core/Config/Config.php b/core/lib/Drupal/Core/Config/Config.php
--- b/core/lib/Drupal/Core/Config/Config.php
+++ b/core/lib/Drupal/Core/Config/Config.php
@@ -193,6 +193,7 @@
    * Saves the configuration object.
    */
   public function save() {
+    $this->validateData($this->data);
     $this->sortByKey($this->data);
     $this->storageDispatcher->selectStorage('write', $this->name)->write($this->name, $this->data);
     $this->isNew = FALSE;
@@ -230,2 +231,34 @@
   }
+
+  /**
+   * Validates configuration data.
+   *
+   * @param array $data
+   *   The configuration data to validate.
+   *
+   * @throws ConfigException
+   */
+  public function validateData(array $data) {
+    array_walk_recursive($data, array('self', 'validateValue'));
+  }
+
+  /**
+   * Validates a configuration value.
+   *
+   * Helper callback for array_walk_recursive().
+   *
+   * @param mixed $value
+   *   The configuration data value to validate.
+   * @param string $key
+   *   The key of the value.
+   *
+   * @throws ConfigException
+   *
+   * @see Config::validateData()
+   */
+  public function validateValue($value, $key) {
+    if (!is_scalar($value)) {
+      throw new ConfigException(sprintf('Unsupported non-scalar value of type %s in key %s in config object %s', gettype($value), $key, $this->name));
+    }
+  }
 }
reverted:
--- b/core/lib/Drupal/Core/Config/DatabaseStorage.php
+++ a/core/lib/Drupal/Core/Config/DatabaseStorage.php
@@ -13,7 +13,7 @@
 /**
  * Defines the Database storage controller.
  */
+class DatabaseStorage implements StorageInterface {
-class DatabaseStorage extends StorageBase {
 
   /**
    * Database connection options for this storage controller.
@@ -77,7 +77,6 @@
    * @todo Ignore slave targets for data manipulation operations.
    */
   public function write($name, array $data) {
-    $this->validateData($name, $data);
     $data = $this->encode($data);
     $options = array('return' => Database::RETURN_AFFECTED) + $this->options;
     return (bool) $this->getConnection()->merge('config', $options)
reverted:
--- b/core/lib/Drupal/Core/Config/FileStorage.php
+++ a/core/lib/Drupal/Core/Config/FileStorage.php
@@ -12,7 +12,7 @@
 /**
  * Defines the file storage controller.
  */
+class FileStorage implements StorageInterface {
-class FileStorage extends StorageBase {
 
   /**
    * Configuration options for this storage controller.
@@ -86,7 +86,6 @@
    * @throws Drupal\Core\Config\StorageException
    */
   public function write($name, array $data) {
-    $this->validateData($name, $data);
     $data = $this->encode($data);
     $status = @file_put_contents($this->getFilePath($name), $data);
     if ($status === FALSE) {
reverted:
--- b/core/lib/Drupal/Core/Config/NullStorage.php
+++ a/core/lib/Drupal/Core/Config/NullStorage.php
@@ -21,7 +21,7 @@
  *
  * This also can be used for testing purposes.
  */
+class NullStorage implements StorageInterface {
-class NullStorage extends StorageBase {
   /**
    * Implements Drupal\Core\Config\StorageInterface::__construct().
    */
reverted:
--- b/core/lib/Drupal/Core/Config/StorageBase.php
+++ /dev/null
@@ -1,35 +0,0 @@
-<?php
-
-/**
- * @file
- * Definition of Drupal\Core\Config\StorageBase.
- */
-
-namespace Drupal\Core\Config;
-
-/**
- * Defines an abstract class for configuration storage controllers.
- *
- * Classes extending this allow reading, writing and validating configuration
- * data from and to the storage.
- */
-abstract class StorageBase implements StorageInterface {
-
-  /**
-   * Implements Drupal\Core\Config\StorageInterface::validateData().
-   */
-  public function validateData($name, array $data) {
-    array_walk_recursive($data, array('self', 'validateValue'), $name);
-  }
-
-  /**
-   * Implements Drupal\Core\Config\StorageInterface::validateValue().
-   */
-  public function validateValue($value, $key, $name) {
-    if (!is_scalar($value)) {
-      throw new StorageException(sprintf('Unsupported non-scalar value of type %s in key %s in config object %s', gettype($value), $key, $name));
-    }
-  }
-}
-
-?>
reverted:
--- b/core/lib/Drupal/Core/Config/StorageInterface.php
+++ a/core/lib/Drupal/Core/Config/StorageInterface.php
@@ -89,36 +89,6 @@
   public static function decode($raw);
 
   /**
-   * Validates configuration data.
-   *
-   * @param string $name
-   *   The name of a configuration object to validate.
-   * @param array $data
-   *   The configuration data to validate.
-   *
-   * @throws StorageException
-   */
-  public function validateData($name, array $data);
-
-  /**
-   * Validates a configuration value.
-   *
-   * Helper callback for array_walk_recursive().
-   *
-   * @param mixed $value
-   *   The configuration data value to validate.
-   * @param string $key
-   *   The key of the value.
-   * @param string $name
-   *   The name of the configuration object.
-   *
-   * @throws StorageException
-   *
-   * @see StorageBase::validateData()
-   */
-  public function validateValue($value, $key, $name);
-
-  /**
    * Gets configuration object names starting with a given prefix.
    *
    * Given the following configuration objects:
diff -u b/core/modules/config/lib/Drupal/config/Tests/ConfigCRUDTest.php b/core/modules/config/lib/Drupal/config/Tests/ConfigCRUDTest.php
--- b/core/modules/config/lib/Drupal/config/Tests/ConfigCRUDTest.php
+++ b/core/modules/config/lib/Drupal/config/Tests/ConfigCRUDTest.php
@@ -9,6 +9,7 @@
 
 use Drupal\Core\Config\DatabaseStorage;
 use Drupal\Core\Config\StorageException;
+use Drupal\Core\Config\ConfigException;
 use Drupal\simpletest\WebTestBase;
 
 /**
@@ -169,7 +170,7 @@
     try {
       $config->save();
     }
-    catch (StorageException $e) {
+    catch (ConfigException $e) {
       $message = $e->getMessage();
     }
     $this->assertEqual($message, 'Unsupported non-scalar value of type resource in key invalid_type in config object config_test.invalid_data');
@@ -180,7 +181,7 @@
     try {
       $config->setData($data)->save();
     }
-    catch (StorageException $e) {
+    catch (ConfigException $e) {
       $message = $e->getMessage();
     }
     $this->assertEqual($message, 'Unsupported non-scalar value of type object in key invalid_type in config object config_test.invalid_data');
diff -u b/core/modules/config/lib/Drupal/config/Tests/Storage/ConfigStorageTestBase.php b/core/modules/config/lib/Drupal/config/Tests/Storage/ConfigStorageTestBase.php
--- b/core/modules/config/lib/Drupal/config/Tests/Storage/ConfigStorageTestBase.php
+++ b/core/modules/config/lib/Drupal/config/Tests/Storage/ConfigStorageTestBase.php
@@ -8,7 +8,6 @@
 namespace Drupal\config\Tests\Storage;
 
 use Drupal\simpletest\WebTestBase;
-use Drupal\Core\Config\StorageException;
 
 /**
  * Base class for testing storage controller operations.
@@ -135,23 +134,6 @@
     $this->assertIdentical($read_data, $data);
   }
 
-  /**
-   * Tests storage controller writing an invalid data type.
-   */
-  function testInvalidData() {
-    $name = 'config_test.invalid_data';
-    $data = array(
-      'invalid_key' => new \stdClass(),
-    );
-    try {
-      $data = $this->storage->write($name, $data);
-    }
-    catch (StorageException $e) {
-      $message = $e->getMessage();
-    }
-    $this->assertEqual($message, sprintf('Unsupported non-scalar value of type object in key invalid_key in config object %s', $name));
-  }
-
   abstract protected function read($name);
 
   abstract protected function insert($name, $data);