diff --git a/config/install/facetapi.facet_source.yml b/config/install/facetapi.facet_source.yml
new file mode 100644
index 0000000..4aa101f
--- /dev/null
+++ b/config/install/facetapi.facet_source.yml
@@ -0,0 +1 @@
+filter_key: f
diff --git a/config/schema/facetapi.facet_source.schema.yml b/config/schema/facetapi.facet_source.schema.yml
new file mode 100644
index 0000000..b9283fa
--- /dev/null
+++ b/config/schema/facetapi.facet_source.schema.yml
@@ -0,0 +1,17 @@
+facetapi.facet_source:
+  type: config_object
+  label : 'Facet'
+  mapping:
+    filter_key:
+      type: string
+      label: 'Filter key'
+    overrides:
+      type: sequence
+      label: 'Overrides'
+      sequence:
+        type: mapping
+        label: 'Override'
+        mapping:
+          filter_key:
+            type: string
+            label: 'Filter key'
diff --git a/facetapi.routing.yml b/facetapi.routing.yml
index dec8f20..0bb1d0b 100644
--- a/facetapi.routing.yml
+++ b/facetapi.routing.yml
@@ -41,3 +41,11 @@ entity.facetapi_facet.display_form:
     _entity_form: 'facetapi_facet.display'
   requirements:
     _entity_access: 'facetapi_facet.edit'
+
+facetapi_facet.facetsource.config_form:
+  path: '/admin/config/search/facet-api/facet-source/{source_id}/edit'
+  defaults:
+    _controller: '\Drupal\facetapi\Controller\FacetSourceConfigController::facetSourceConfigForm'
+    _title: 'Edit facet source configuration'
+  requirements:
+    _entity_create_access: 'facetapi_facet'
diff --git a/src/Controller/FacetSourceConfigController.php b/src/Controller/FacetSourceConfigController.php
new file mode 100644
index 0000000..16e8f00
--- /dev/null
+++ b/src/Controller/FacetSourceConfigController.php
@@ -0,0 +1,48 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\facetapi\Controller\FacetSourceConfigController.
+ */
+
+namespace Drupal\facetapi\Controller;
+
+use Drupal\Component\Plugin\Exception\PluginNotFoundException;
+use Drupal\Core\Controller\ControllerBase;
+
+/**
+ * Provides route responses for facet source configuration.
+ */
+class FacetSourceConfigController extends ControllerBase {
+
+  /**
+   * Configuration for the facet source.
+   *
+   * @param string $source_id
+   *   The plugin id.
+   *
+   * @return array
+   *   A renderable array containing the form.
+   */
+  public function facetSourceConfigForm($source_id) {
+    /** @var \Drupal\facetapi\FacetSource\FacetSourcePluginManager $facet_source_plugin_manager */
+    $facet_source_plugin_manager = \Drupal::service('plugin.manager.facetapi.facet_source');
+
+    try {
+      $facet_source_plugin_manager->createInstance($source_id);
+    } catch (PluginNotFoundException $e) {
+      // Return a renderable array with a plugin not found message. We add a
+      // max-age to make sure that this message is not found indefinitely.
+      return [
+        '#markup' => $this->t('Plugin not found.'),
+        '#cache' => [
+          'max-age' => 5,
+        ]
+      ];
+    }
+
+    // Returns the render array of the FacetSourceConfigForm.
+    return $this->formBuilder()->getForm('\Drupal\facetapi\Form\FacetSourceConfigForm');
+  }
+
+}
diff --git a/src/FacetListBuilder.php b/src/FacetListBuilder.php
index 43e801d..de19305 100644
--- a/src/FacetListBuilder.php
+++ b/src/FacetListBuilder.php
@@ -10,7 +10,7 @@ namespace Drupal\facetapi;
 use Drupal\Core\Config\Entity\ConfigEntityInterface;
 use Drupal\Core\Config\Entity\ConfigEntityListBuilder;
 use Drupal\Core\Entity\EntityInterface;
-use Drupal\facetapi\FacetSource\FacetSourceInterface;
+use Drupal\Core\Link;
 
 /**
  * Builds a listing of facet entities.
@@ -135,7 +135,9 @@ class FacetListBuilder extends ConfigEntityListBuilder {
         'status' => array(
           'data' => '',
         ),
-        'operations' => array(),
+        'operations' => array(
+          'data' => Link::createFromRoute('Configure', 'facetapi_facet.facetsource.config_form', ['source_id' => $facet_source['id']])->toRenderable()
+        ),
       ),
       'class' => array('facet-source'),
     );
diff --git a/src/Form/FacetSourceConfigForm.php b/src/Form/FacetSourceConfigForm.php
new file mode 100644
index 0000000..491be51
--- /dev/null
+++ b/src/Form/FacetSourceConfigForm.php
@@ -0,0 +1,79 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\facetapi\Form\FacetSourceConfigForm.
+ */
+
+namespace Drupal\facetapi\Form;
+
+use Drupal\Core\Form\ConfigFormBase;
+use Drupal\Core\Form\FormStateInterface;
+
+/**
+ * Provides a form for creating and editing facet source config overrides.
+ */
+class FacetSourceConfigForm extends ConfigFormBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getFormId() {
+    return 'facet_source_config_form';
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getEditableConfigNames() {
+    return ['facetapi.facet_source'];
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function buildForm(array $form, FormStateInterface $form_state) {
+    $config = $this->config('facetapi.facet_source');
+    $facet_source_id = $this->getRequest()->get('source_id');
+    $overridden_filter_key_config = $config->get('overrides.' . $facet_source_id . '.filter_key');
+
+    $form['description'] = [
+      '#markup' => $this->t('Saving this form will create a configuration override for this specific facet source.
+      Unless you have to override facet source specific configuration, you can leave this to the default settings.')
+    ];
+
+    $form['facet_source_id'] = [
+      '#type' => 'hidden',
+      '#value' => $facet_source_id,
+    ];
+
+    // Filter key setting.
+    $form['filter_key'] = [
+      '#type' => 'textfield',
+      '#title' => $this->t('Filter key'),
+      '#size' => 20,
+      '#maxlength' => 255,
+      '#default_value' => (!is_null($overridden_filter_key_config) ? $overridden_filter_key_config : $config->get('filter_key')),
+      '#description' => $this->t('They key used for filtering in the URL, defaults to f.
+      You should change this to something else if you expect to have multiple facet sources on one page.'),
+    ];
+
+    // The parent's form build method will add a save button.
+    return parent::buildForm($form, $form_state);
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function submitForm(array &$form, FormStateInterface $form_state) {
+    // The parent's submitForm adds a message.
+    parent::submitForm($form, $form_state);
+
+    // When saving the config, make sure it's saved in the
+    // 'overrides.facetsourceid.*' config name, so we can make sure that config
+    // is possible to be overridden per facet source.
+    $config = $this->config('facetapi.facet_source');
+    $config->set('overrides.' . $form_state->getValue('facet_source_id') . '.filter_key', $form_state->getValue('filter_key'));
+    $config->save();
+  }
+}
diff --git a/src/Plugin/facetapi/processor/QueryStringUrlProcessor.php b/src/Plugin/facetapi/processor/QueryStringUrlProcessor.php
index 709e12f..0d1c310 100644
--- a/src/Plugin/facetapi/processor/QueryStringUrlProcessor.php
+++ b/src/Plugin/facetapi/processor/QueryStringUrlProcessor.php
@@ -7,6 +7,7 @@
 
 namespace Drupal\facetapi\Plugin\facetapi\processor;
 
+use Drupal\Core\Config\ConfigFactoryInterface;
 use Drupal\Core\Url;
 use Drupal\facetapi\FacetInterface;
 use Drupal\facetapi\Processor\UrlProcessorPluginBase;
@@ -40,8 +41,8 @@ class QueryStringUrlProcessor extends UrlProcessorPluginBase {
   /**
    * {@inheritdoc}
    */
-  public function __construct(array $configuration, $plugin_id, $plugin_definition, Request $request) {
-    parent::__construct($configuration, $plugin_id, $plugin_definition, $request);
+  public function __construct(array $configuration, $plugin_id, $plugin_definition, Request $request, ConfigFactoryInterface $config_factory) {
+    parent::__construct($configuration, $plugin_id, $plugin_definition, $request, $config_factory);
     $this->initializeActiveFilters();
   }
 
diff --git a/src/Processor/UrlProcessorPluginBase.php b/src/Processor/UrlProcessorPluginBase.php
index 7a3e94d..c9fd324 100644
--- a/src/Processor/UrlProcessorPluginBase.php
+++ b/src/Processor/UrlProcessorPluginBase.php
@@ -6,6 +6,7 @@
 
 namespace Drupal\facetapi\Processor;
 
+use Drupal\Core\Config\ConfigFactoryInterface;
 use Drupal\Core\Plugin\ContainerFactoryPluginInterface;
 use Symfony\Component\DependencyInjection\ContainerInterface;
 use Symfony\Component\HttpFoundation\Request;
@@ -41,10 +42,26 @@ abstract class UrlProcessorPluginBase extends ProcessorPluginBase implements Url
    * @param string $plugin_id
    * @param mixed $plugin_definition
    * @param \Symfony\Component\HttpFoundation\Request $request
+   * @param \Drupal\Core\Config\ConfigFactoryInterface $config_factory
+   *   An instance of the config factory
    */
-  public function __construct(array $configuration, $plugin_id, $plugin_definition, Request $request) {
+  public function __construct(array $configuration, $plugin_id, $plugin_definition, Request $request, ConfigFactoryInterface $config_factory) {
     parent::__construct($configuration, $plugin_id, $plugin_definition);
     $this->request = $request;
+
+    $facetSourceId = $configuration['facet']->getFacetSourceId();
+
+    $facetSourceConfig = $config_factory->get('facetapi.facet_source');
+
+    // Set the filter key from the global config.
+    $this->filter_key = $facetSourceConfig->get('filter_key');
+
+    // Check if the filter key has been overridden in facet source specific
+    // config.
+    $override = $facetSourceConfig->get('overrides.' . $facetSourceId . '.filter_key');
+    if (!is_null($override)) {
+      $this->filter_key = $override;
+    }
   }
 
   /**
@@ -53,7 +70,11 @@ abstract class UrlProcessorPluginBase extends ProcessorPluginBase implements Url
   public static function create(ContainerInterface $container, array $configuration, $plugin_id, $plugin_definition) {
     /** @var Request $request */
     $request = $container->get('request_stack')->getCurrentRequest();
-    return new static($configuration, $plugin_id, $plugin_definition, $request);
+
+    /** @var \Drupal\Core\Config\ConfigFactory $configFactory */
+    $configFactory = $container->get('config.factory');
+
+    return new static($configuration, $plugin_id, $plugin_definition, $request, $configFactory);
   }
 
 }
diff --git a/tests/src/Unit/Plugin/processor/QueryStringUrlProcessorTest.php b/tests/src/Unit/Plugin/processor/QueryStringUrlProcessorTest.php
index ad41c24..1903ea6 100644
--- a/tests/src/Unit/Plugin/processor/QueryStringUrlProcessorTest.php
+++ b/tests/src/Unit/Plugin/processor/QueryStringUrlProcessorTest.php
@@ -35,6 +35,11 @@ class QueryStringUrlProcessorTest extends UnitTestCase {
   protected $original_results;
 
   /**
+   * A mocked config storage stub.
+   */
+  protected $config;
+
+  /**
    * Creates a new processor object for use in the tests.
    */
   protected function setUp() {
@@ -47,6 +52,8 @@ class QueryStringUrlProcessorTest extends UnitTestCase {
       new Result('duck', 'Duck', 15),
       new Result('alpaca', 'Alpaca', 25),
     ];
+
+    $this->config = $this->getConfigFactoryStub(['facetapi.facet_source' => ['filter_key' => 'f']]);
   }
 
   public function testSetSingleActiveItem() {
@@ -57,7 +64,7 @@ class QueryStringUrlProcessorTest extends UnitTestCase {
     $request = new Request;
     $request->query->set('f', ['test:badger']);
 
-    $this->processor = new QueryStringUrlProcessor([], 'query_string', [], $request);
+    $this->processor = new QueryStringUrlProcessor(['facet' => $facet], 'query_string', [], $request, $this->config);
     $this->processor->preQuery($facet);
 
     $this->assertEquals(['badger'], $facet->getActiveItems());
@@ -71,9 +78,59 @@ class QueryStringUrlProcessorTest extends UnitTestCase {
     $request = new Request;
     $request->query->set('f', ['test:badger', 'test:mushroom', 'donkey:kong']);
 
-    $this->processor = new QueryStringUrlProcessor([], 'query_string', [], $request);
+    $this->processor = new QueryStringUrlProcessor(['facet' => $facet], 'query_string', [], $request, $this->config);
+    $this->processor->preQuery($facet);
+
+    $this->assertEquals(['badger', 'mushroom'], $facet->getActiveItems());
+  }
+
+  public function testSetActiveWithConfigOverride() {
+    $facet = new Facet([], 'facet');
+    $facet->setResults($this->original_results);
+    $facet->setFieldIdentifier('test');
+
+    $config = $this->getConfigFactoryStub(['facetapi.facet_source' => ['filter_key' => 'g']]);
+
+    $request = new Request;
+    $request->query->set('f', ['test:badger', 'test:mushroom', 'donkey:kong']);
+
+    $this->processor = new QueryStringUrlProcessor(['facet' => $facet], 'query_string', [], $request, $config);
     $this->processor->preQuery($facet);
 
+
+    // Configuration was globally overridden but the request was still using the
+    // old 'f' parameter. This means there are no active items found in the
+    // request.
+    $this->assertEquals([], $facet->getActiveItems());
+
+    $request = new Request;
+    $request->query->set('g', ['test:badger', 'test:mushroom', 'donkey:kong']);
+
+    $this->processor = new QueryStringUrlProcessor(['facet' => $facet], 'query_string', [], $request, $config);
+    $this->processor->preQuery($facet);
+
+    // Now that the request also uses 'g' as query parameter, we expect the same
+    // response as ::testSetMultipleActiveItems expects.
+    $this->assertEquals(['badger', 'mushroom'], $facet->getActiveItems());
+  }
+
+  public function testFacetSourceOverride() {
+    $facet = new Facet([], 'facet');
+    $facet->setResults($this->original_results);
+    $facet->setFieldIdentifier('test');
+    $facet->setFacetSourceId('fs');
+
+    $config = $this->getConfigFactoryStub(['facetapi.facet_source' => ['filter_key' => 'f', 'overrides.fs.filter_key' => 'aa']]);
+
+    $request = new Request;
+    $request->query->set('aa', ['test:badger', 'test:mushroom', 'donkey:kong']);
+
+    $processor = new QueryStringUrlProcessor(['facet' => $facet], 'query_string', [], $request, $config);
+    $processor->preQuery($facet);
+
+    // The request uses 'aa' in the parameter, this is the same as what was set
+    // in the config override and thus we should get badger and mushroom as
+    // active items.
     $this->assertEquals(['badger', 'mushroom'], $facet->getActiveItems());
   }
 
@@ -83,7 +140,7 @@ class QueryStringUrlProcessorTest extends UnitTestCase {
     $request = new Request;
     $request->query->set('f', []);
 
-    $this->processor = new QueryStringUrlProcessor([], 'query_string', [], $request);
+    $this->processor = new QueryStringUrlProcessor(['facet' => $facet], 'query_string', [], $request, $this->config);
     $results = $this->processor->build($facet, []);
     $this->assertEmpty($results);
   }
@@ -97,7 +154,7 @@ class QueryStringUrlProcessorTest extends UnitTestCase {
 
     $this->setRouter();
 
-    $this->processor = new QueryStringUrlProcessor([], 'query_string', [], $request);
+    $this->processor = new QueryStringUrlProcessor(['facet' => $facet], 'query_string', [], $request, $this->config);
     $results = $this->processor->build($facet, $this->original_results);
 
     /** @var \Drupal\facetapi\Result\ResultInterface $r */
@@ -119,7 +176,7 @@ class QueryStringUrlProcessorTest extends UnitTestCase {
 
     $this->setRouter();
 
-    $this->processor = new QueryStringUrlProcessor([], 'query_string', [], $request);
+    $this->processor = new QueryStringUrlProcessor(['facet' => $facet], 'query_string', [], $request, $this->config);
     $results = $this->processor->build($facet, $original_results);
 
     /** @var \Drupal\facetapi\Result\ResultInterface $r */