diff --git a/src/stream/src/executor/agg_common.rs b/src/stream/src/executor/agg_common.rs
index 2e32c297113c2..1ef9500457345 100644
--- a/src/stream/src/executor/agg_common.rs
+++ b/src/stream/src/executor/agg_common.rs
@@ -40,6 +40,7 @@ pub struct AggExecutorArgs<S: StateStore> {
     pub storages: Vec<AggStateStorage<S>>,
     pub result_table: StateTable<S>,
     pub distinct_dedup_tables: HashMap<usize, StateTable<S>>,
+    pub watermark_epoch: AtomicU64Ref,
 
     // extra
     pub extra: Option<AggExecutorArgsExtra>,
@@ -53,5 +54,4 @@ pub struct AggExecutorArgsExtra {
     // things only used by hash agg currently
     pub metrics: Arc<StreamingMetrics>,
     pub chunk_size: usize,
-    pub watermark_epoch: AtomicU64Ref,
 }
diff --git a/src/stream/src/executor/global_simple_agg.rs b/src/stream/src/executor/global_simple_agg.rs
index 5bdcc14996924..880b759ab2f5d 100644
--- a/src/stream/src/executor/global_simple_agg.rs
+++ b/src/stream/src/executor/global_simple_agg.rs
@@ -12,8 +12,6 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-use std::sync::atomic::AtomicU64;
-
 use futures::StreamExt;
 use futures_async_stream::try_stream;
 use risingwave_common::array::StreamChunk;
@@ -32,6 +30,7 @@ use crate::error::StreamResult;
 use crate::executor::aggregation::{generate_agg_schema, AggCall, AggGroup};
 use crate::executor::error::StreamExecutorError;
 use crate::executor::{BoxedMessageStream, Message};
+use crate::task::AtomicU64Ref;
 
 /// `GlobalSimpleAggExecutor` is the aggregation operator for streaming system.
 /// To create an aggregation operator, states and expressions should be passed along the
@@ -76,6 +75,9 @@ struct ExecutorInner<S: StateStore> {
     /// One table per distinct column (may be shared by multiple agg calls).
     distinct_dedup_tables: HashMap<usize, StateTable<S>>,
 
+    /// Watermark epoch.
+    watermark_epoch: AtomicU64Ref,
+
     /// Extreme state cache size
     extreme_cache_size: usize,
 }
@@ -140,6 +142,7 @@ impl<S: StateStore> GlobalSimpleAggExecutor<S> {
                 storages: args.storages,
                 result_table: args.result_table,
                 distinct_dedup_tables: args.distinct_dedup_tables,
+                watermark_epoch: args.watermark_epoch,
                 extreme_cache_size: args.extreme_cache_size,
             },
         })
@@ -306,10 +309,7 @@ impl<S: StateStore> GlobalSimpleAggExecutor<S> {
                 &this.input_schema,
             )
             .await?,
-            distinct_dedup: DistinctDeduplicater::new(
-                &this.agg_calls,
-                &Arc::new(AtomicU64::new(0)), // TODO(rc): use real watermark epoch?
-            ),
+            distinct_dedup: DistinctDeduplicater::new(&this.agg_calls, &this.watermark_epoch),
             state_changed: false,
         };
 
diff --git a/src/stream/src/executor/hash_agg.rs b/src/stream/src/executor/hash_agg.rs
index 582fd734f1e98..03e0774f595dd 100644
--- a/src/stream/src/executor/hash_agg.rs
+++ b/src/stream/src/executor/hash_agg.rs
@@ -96,7 +96,7 @@ struct ExecutorInner<K: HashKey, S: StateStore> {
     /// One table per distinct column (may be shared by multiple agg calls).
     distinct_dedup_tables: HashMap<usize, StateTable<S>>,
 
-    /// Lru manager. None if using local eviction.
+    /// Watermark epoch.
     watermark_epoch: AtomicU64Ref,
 
     /// The maximum size of the chunk produced by executor at a time.
@@ -199,7 +199,7 @@ impl<K: HashKey, S: StateStore> HashAggExecutor<K, S> {
                 storages: args.storages,
                 result_table: args.result_table,
                 distinct_dedup_tables: args.distinct_dedup_tables,
-                watermark_epoch: extra_args.watermark_epoch,
+                watermark_epoch: args.watermark_epoch,
                 chunk_size: extra_args.chunk_size,
                 extreme_cache_size: args.extreme_cache_size,
                 metrics: extra_args.metrics,
@@ -685,13 +685,13 @@ mod tests {
             storages,
             result_table,
             distinct_dedup_tables: Default::default(),
+            watermark_epoch: Arc::new(AtomicU64::new(0)),
 
             extra: Some(AggExecutorArgsExtra {
                 group_key_indices,
 
                 metrics: Arc::new(StreamingMetrics::unused()),
                 chunk_size: 1024,
-                watermark_epoch: Arc::new(AtomicU64::new(0)),
             }),
         })
         .unwrap()
diff --git a/src/stream/src/executor/test_utils.rs b/src/stream/src/executor/test_utils.rs
index 1597f79252291..3773370a48b22 100644
--- a/src/stream/src/executor/test_utils.rs
+++ b/src/stream/src/executor/test_utils.rs
@@ -207,6 +207,9 @@ pub trait StreamExecutorTestExt: MessageStream + Unpin {
 impl StreamExecutorTestExt for BoxedMessageStream {}
 
 pub mod agg_executor {
+    use std::sync::atomic::AtomicU64;
+    use std::sync::Arc;
+
     use risingwave_common::catalog::{ColumnDesc, ColumnId, TableId};
     use risingwave_common::types::DataType;
     use risingwave_common::util::sort_util::OrderType;
@@ -374,6 +377,7 @@ pub mod agg_executor {
             storages,
             result_table,
             distinct_dedup_tables: Default::default(),
+            watermark_epoch: Arc::new(AtomicU64::new(0)),
 
             extra: None,
         })
diff --git a/src/stream/src/from_proto/global_simple_agg.rs b/src/stream/src/from_proto/global_simple_agg.rs
index e9147c8b4f3a5..d78fb26107da8 100644
--- a/src/stream/src/from_proto/global_simple_agg.rs
+++ b/src/stream/src/from_proto/global_simple_agg.rs
@@ -66,6 +66,7 @@ impl ExecutorBuilder for GlobalSimpleAggExecutorBuilder {
             storages,
             result_table,
             distinct_dedup_tables,
+            watermark_epoch: stream.get_watermark_epoch(),
 
             extra: None,
         })?
diff --git a/src/stream/src/from_proto/hash_agg.rs b/src/stream/src/from_proto/hash_agg.rs
index ca94c7a69e271..417a166f020eb 100644
--- a/src/stream/src/from_proto/hash_agg.rs
+++ b/src/stream/src/from_proto/hash_agg.rs
@@ -108,13 +108,13 @@ impl ExecutorBuilder for HashAggExecutorBuilder {
                 storages,
                 result_table,
                 distinct_dedup_tables,
+                watermark_epoch: stream.get_watermark_epoch(),
 
                 extra: Some(AggExecutorArgsExtra {
                     group_key_indices,
 
                     metrics: params.executor_stats,
                     chunk_size: params.env.config().developer.stream_chunk_size,
-                    watermark_epoch: stream.get_watermark_epoch(),
                 }),
             },
             group_key_types,