diff --git a/common-tools/clas-detector/src/main/java/org/jlab/detector/calib/utils/OccupancyTable.java b/common-tools/clas-detector/src/main/java/org/jlab/detector/calib/utils/OccupancyTable.java
new file mode 100644
index 0000000000..aca5de13c2
--- /dev/null
+++ b/common-tools/clas-detector/src/main/java/org/jlab/detector/calib/utils/OccupancyTable.java
@@ -0,0 +1,94 @@
+package org.jlab.detector.calib.utils;
+
+import java.util.Map;
+import org.jlab.io.base.DataBank;
+import org.jlab.utils.groups.IndexedTable;
+
+/**
+ * Utility class for storing occupancy/multiplicity in an IndexedTable and
+ * writing it to an occupancy bank with format (index... weight [*])
+ * 
+ * @author baltzell
+ */
+public class OccupancyTable {
+
+    private String[] indexNames;
+    private IndexedTable table;
+
+    public OccupancyTable(String... index) {
+        if (index.length != 3 && index.length != 4)
+            throw new IllegalArgumentException("Invalid index length: "+index.length);
+        indexNames = index;
+        table = new IndexedTable(indexNames.length, new String[]{"occ/D"});
+    }
+
+    /**
+     * Reset the occupancy table.
+     */
+    public void reset() {
+        table = new IndexedTable(indexNames.length, new String[]{"occ/D"});
+    }
+
+    /**
+     * Fill occupancy, user-defined weight.
+     * @param weight
+     * @param index 
+     */
+    public void add(double weight, int... index) {
+        final long hash = IndexedTable.DEFAULT_GENERATOR.hashCode(index);
+        if (!table.hasEntry(index)) {
+            table.addEntry(index);
+            table.setDoubleValueByHash(0.0, indexNames.length, hash);
+        }
+        table.setDoubleValueByHash(weight + table.getDoubleValueByHash(indexNames.length, hash), indexNames.length, hash);
+    }
+
+    /**
+     * Fill occupancy, unity weight.
+     * @param index 
+     */
+    public void add(int... index) {
+        add(1, index);
+    }
+
+    /**
+     * Fill occupancy from hits bank, one per bank row.
+     * Note, bank index data types are hard-coded here! 
+     * @param b hit bank
+     */
+    public void add(DataBank b) {
+        final int rows = b.rows();
+        for (int i=0; i<rows; i++) {
+            if (indexNames.length == 3)
+                add(b.getByte(0, i), b.getByte(1,i), b.getShort(2,i));
+            else
+                add(b.getByte(0, i), b.getByte(1,i), b.getShort(2,i), b.getByte(3,i));
+        }
+    }
+
+    /**
+     * Get the number of rows for the occupancy bank.
+     * @return rows 
+     */
+    public int getRows() {
+        return table.getRowCount();
+    }
+   
+    /**
+     * Update an occupancy bank.
+     * @param b occupancy bank
+     */
+    public void update(DataBank b) {
+        int i = 0;
+        Map<Long,Integer> m = table.getList().getMap();
+        for (Map.Entry<Long,Integer> entry : m.entrySet()) {
+            b.setInt(0, i, IndexedTable.DEFAULT_GENERATOR.getIndex(entry.getKey(), 0));
+            b.setInt(1, i, IndexedTable.DEFAULT_GENERATOR.getIndex(entry.getKey(), 1));
+            b.setInt(2, i, IndexedTable.DEFAULT_GENERATOR.getIndex(entry.getKey(), 2));
+            if (indexNames.length == 4)
+                b.setInt(3, i, IndexedTable.DEFAULT_GENERATOR.getIndex(entry.getKey(), 3));
+            b.setInt(indexNames.length, i, entry.getValue());
+            i++;
+        }
+    }
+}
\ No newline at end of file
diff --git a/common-tools/clas-utils/src/main/java/org/jlab/utils/groups/IndexedTable.java b/common-tools/clas-utils/src/main/java/org/jlab/utils/groups/IndexedTable.java
index 28dcdf629d..a82bd23715 100644
--- a/common-tools/clas-utils/src/main/java/org/jlab/utils/groups/IndexedTable.java
+++ b/common-tools/clas-utils/src/main/java/org/jlab/utils/groups/IndexedTable.java
@@ -167,6 +167,10 @@ public void setIntValueByHash(Integer value, int column, long hash) {
         this.entries.getItemByHash(hash).setValue(column, value);
     }
 
+    public void setDoubleValueByHash(Double value, int column, long hash) {
+        this.entries.getItemByHash(hash).setValue(column, value);
+    }
+
     public int getIntValueByHash(int index, long hash) {
         return entries.getItemByHash(hash).getValue(index).intValue();
     }
diff --git a/etc/bankdefs/hipo4/occupancy.json b/etc/bankdefs/hipo4/occupancy.json
new file mode 100644
index 0000000000..82722ec54f
--- /dev/null
+++ b/etc/bankdefs/hipo4/occupancy.json
@@ -0,0 +1,14 @@
+[
+    {
+        "name": "DC::occ",
+        "group": 20600,
+        "item": 20,
+        "info": "Event Header Bank",
+        "entries": [
+            { "name":"sector"    , "type":"B", "info":"sector"},
+            { "name":"layer"     , "type":"B", "info":"layer"},
+            { "name":"component" , "type":"S", "info":"component"},
+            { "name":"hits"      , "type":"S", "info":"number of hits"}
+        ]
+    }
+]