diff --git a/core/src/main/java/org/elasticsearch/cluster/ClusterModule.java b/core/src/main/java/org/elasticsearch/cluster/ClusterModule.java
index fd720513fb7..fba16641ca3 100644
--- a/core/src/main/java/org/elasticsearch/cluster/ClusterModule.java
+++ b/core/src/main/java/org/elasticsearch/cluster/ClusterModule.java
@@ -131,7 +131,6 @@ public class ClusterModule extends AbstractModule {
         registerIndexDynamicSetting(IndexMetaData.SETTING_SHARED_FS_ALLOW_RECOVERY_ON_ANY_NODE, Validator.EMPTY);
         registerIndexDynamicSetting(IndexMetaData.SETTING_PRIORITY, Validator.NON_NEGATIVE_INTEGER);
         registerIndexDynamicSetting(PrimaryShardAllocator.INDEX_RECOVERY_INITIAL_SHARDS, Validator.EMPTY);
-        registerIndexDynamicSetting(MergePolicyConfig.INDEX_MERGE_POLICY_EXPUNGE_DELETES_ALLOWED, Validator.DOUBLE);
         registerIndexDynamicSetting(MergePolicyConfig.INDEX_MERGE_POLICY_FLOOR_SEGMENT, Validator.BYTES_SIZE);
         registerIndexDynamicSetting(MergePolicyConfig.INDEX_MERGE_POLICY_MAX_MERGE_AT_ONCE, Validator.INTEGER_GTE_2);
         registerIndexDynamicSetting(MergePolicyConfig.INDEX_MERGE_POLICY_MAX_MERGE_AT_ONCE_EXPLICIT, Validator.INTEGER_GTE_2);
diff --git a/core/src/main/java/org/elasticsearch/index/MergePolicyConfig.java b/core/src/main/java/org/elasticsearch/index/MergePolicyConfig.java
index 0fa59bc317f..e6bffad2295 100644
--- a/core/src/main/java/org/elasticsearch/index/MergePolicyConfig.java
+++ b/core/src/main/java/org/elasticsearch/index/MergePolicyConfig.java
@@ -128,7 +128,7 @@ public final class MergePolicyConfig {
     public static final double          DEFAULT_RECLAIM_DELETES_WEIGHT      = 2.0d;
     public static final Setting<Double> INDEX_COMPOUND_FORMAT_SETTING       = new Setting<>("index.compound_format", Double.toString(TieredMergePolicy.DEFAULT_NO_CFS_RATIO), MergePolicyConfig::parseNoCFSRatio, true, Setting.Scope.INDEX);
 
-    public static final String INDEX_MERGE_POLICY_EXPUNGE_DELETES_ALLOWED = "index.merge.policy.expunge_deletes_allowed";
+    public static final Setting<Double> INDEX_MERGE_POLICY_EXPUNGE_DELETES_ALLOWED_SETTING = Setting.doubleSetting("index.merge.policy.expunge_deletes_allowed", DEFAULT_EXPUNGE_DELETES_ALLOWED, 0.0d, true, Setting.Scope.INDEX);
     public static final String INDEX_MERGE_POLICY_FLOOR_SEGMENT = "index.merge.policy.floor_segment";
     public static final String INDEX_MERGE_POLICY_MAX_MERGE_AT_ONCE = "index.merge.policy.max_merge_at_once";
     public static final String INDEX_MERGE_POLICY_MAX_MERGE_AT_ONCE_EXPLICIT = "index.merge.policy.max_merge_at_once_explicit";
@@ -141,6 +141,7 @@ public final class MergePolicyConfig {
      MergePolicyConfig(ESLogger logger, IndexSettings indexSettings) {
         this.logger = logger;
         indexSettings.addSettingsUpdateConsumer(INDEX_COMPOUND_FORMAT_SETTING, this::setNoCFSRatio);
+         indexSettings.addSettingsUpdateConsumer(INDEX_MERGE_POLICY_EXPUNGE_DELETES_ALLOWED_SETTING, this::expungeDeletesAllowed);
         double forceMergeDeletesPctAllowed = indexSettings.getSettings().getAsDouble("index.merge.policy.expunge_deletes_allowed", DEFAULT_EXPUNGE_DELETES_ALLOWED); // percentage
         ByteSizeValue floorSegment = indexSettings.getSettings().getAsBytesSize("index.merge.policy.floor_segment", DEFAULT_FLOOR_SEGMENT);
         int maxMergeAtOnce = indexSettings.getSettings().getAsInt("index.merge.policy.max_merge_at_once", DEFAULT_MAX_MERGE_AT_ONCE);
@@ -166,6 +167,10 @@ public final class MergePolicyConfig {
                 forceMergeDeletesPctAllowed, floorSegment, maxMergeAtOnce, maxMergeAtOnceExplicit, maxMergedSegment, segmentsPerTier, reclaimDeletesWeight);
     }
 
+    private void expungeDeletesAllowed(Double value) {
+        mergePolicy.setForceMergeDeletesPctAllowed(value);
+    }
+
     private void setNoCFSRatio(Double noCFSRatio) {
         mergePolicy.setNoCFSRatio(noCFSRatio);
     }
@@ -189,13 +194,6 @@ public final class MergePolicyConfig {
     }
 
     void onRefreshSettings(Settings settings) {
-        final double oldExpungeDeletesPctAllowed = mergePolicy.getForceMergeDeletesPctAllowed();
-        final double expungeDeletesPctAllowed = settings.getAsDouble(INDEX_MERGE_POLICY_EXPUNGE_DELETES_ALLOWED, oldExpungeDeletesPctAllowed);
-        if (expungeDeletesPctAllowed != oldExpungeDeletesPctAllowed) {
-            logger.info("updating [expunge_deletes_allowed] from [{}] to [{}]", oldExpungeDeletesPctAllowed, expungeDeletesPctAllowed);
-            mergePolicy.setForceMergeDeletesPctAllowed(expungeDeletesPctAllowed);
-        }
-
         final double oldFloorSegmentMB = mergePolicy.getFloorSegmentMB();
         final ByteSizeValue floorSegment = settings.getAsBytesSize(INDEX_MERGE_POLICY_FLOOR_SEGMENT, null);
         if (floorSegment != null && floorSegment.mbFrac() != oldFloorSegmentMB) {
diff --git a/core/src/test/java/org/elasticsearch/index/MergePolicySettingsTests.java b/core/src/test/java/org/elasticsearch/index/MergePolicySettingsTests.java
index 48592832b82..10c3d51162b 100644
--- a/core/src/test/java/org/elasticsearch/index/MergePolicySettingsTests.java
+++ b/core/src/test/java/org/elasticsearch/index/MergePolicySettingsTests.java
@@ -83,8 +83,10 @@ public class MergePolicySettingsTests extends ESTestCase {
         assertThat(mp.getMergePolicy().getNoCFSRatio(), equalTo(0.1));
 
         assertEquals(((TieredMergePolicy) mp.getMergePolicy()).getForceMergeDeletesPctAllowed(), MergePolicyConfig.DEFAULT_EXPUNGE_DELETES_ALLOWED, 0.0d);
-        mp.onRefreshSettings(Settings.builder().put(MergePolicyConfig.INDEX_MERGE_POLICY_EXPUNGE_DELETES_ALLOWED, MergePolicyConfig.DEFAULT_EXPUNGE_DELETES_ALLOWED + 1.0d).build());
-        assertEquals(((TieredMergePolicy) mp.getMergePolicy()).getForceMergeDeletesPctAllowed(), MergePolicyConfig.DEFAULT_EXPUNGE_DELETES_ALLOWED + 1.0d, 0.0d);
+
+        IndexSettings indexSettings = indexSettings(Settings.EMPTY);
+        indexSettings.updateIndexMetaData(newIndexMeta("index", Settings.builder().put(MergePolicyConfig.INDEX_MERGE_POLICY_EXPUNGE_DELETES_ALLOWED_SETTING.getKey(), MergePolicyConfig.DEFAULT_EXPUNGE_DELETES_ALLOWED + 1.0d).build()));
+        assertEquals(((TieredMergePolicy) indexSettings.getMergePolicy()).getForceMergeDeletesPctAllowed(), MergePolicyConfig.DEFAULT_EXPUNGE_DELETES_ALLOWED + 1.0d, 0.0d);
 
         assertEquals(((TieredMergePolicy) mp.getMergePolicy()).getFloorSegmentMB(), MergePolicyConfig.DEFAULT_FLOOR_SEGMENT.mbFrac(), 0);
         mp.onRefreshSettings(Settings.builder().put(MergePolicyConfig.INDEX_MERGE_POLICY_FLOOR_SEGMENT, new ByteSizeValue(MergePolicyConfig.DEFAULT_FLOOR_SEGMENT.mb() + 1, ByteSizeUnit.MB)).build());
@@ -111,8 +113,9 @@ public class MergePolicySettingsTests extends ESTestCase {
         assertEquals(((TieredMergePolicy) mp.getMergePolicy()).getSegmentsPerTier(), MergePolicyConfig.DEFAULT_SEGMENTS_PER_TIER + 1, 0);
 
         mp.onRefreshSettings(EMPTY_SETTINGS); // update without the settings and see if we stick to the values
-
-        assertEquals(((TieredMergePolicy) mp.getMergePolicy()).getForceMergeDeletesPctAllowed(), MergePolicyConfig.DEFAULT_EXPUNGE_DELETES_ALLOWED + 1.0d, 0.0d);
+        indexSettings.updateIndexMetaData(newIndexMeta("index", EMPTY_SETTINGS));
+        // this will fail because we now reset each setting which is not passed with the sttings update. are we sure this is the desired behavior?
+        assertEquals(((TieredMergePolicy) indexSettings.getMergePolicy()).getForceMergeDeletesPctAllowed(), MergePolicyConfig.DEFAULT_EXPUNGE_DELETES_ALLOWED + 1.0d, 0.0d);
         assertEquals(((TieredMergePolicy) mp.getMergePolicy()).getFloorSegmentMB(), new ByteSizeValue(MergePolicyConfig.DEFAULT_FLOOR_SEGMENT.mb() + 1, ByteSizeUnit.MB).mbFrac(), 0.001);
         assertEquals(((TieredMergePolicy) mp.getMergePolicy()).getMaxMergeAtOnce(), MergePolicyConfig.DEFAULT_MAX_MERGE_AT_ONCE-1);
         assertEquals(((TieredMergePolicy) mp.getMergePolicy()).getMaxMergeAtOnceExplicit(), MergePolicyConfig.DEFAULT_MAX_MERGE_AT_ONCE_EXPLICIT-1);