diff --git a/data_platform/ops/elementary.py b/data_platform/ops/elementary.py
index 83525b5..e1f024f 100644
--- a/data_platform/ops/elementary.py
+++ b/data_platform/ops/elementary.py
@@ -10,7 +10,17 @@ from sqlalchemy import create_engine, text
 _DBT_DIR = Path(__file__).parents[2] / "dbt"
 
 
-def _elementary_schema_exists() -> bool:
+_DAYS_BACK = 3
+
+_CLEANUP_TABLES = [
+    "elementary_test_results",
+    "dbt_run_results",
+    "dbt_invocations",
+    "dbt_source_freshness_results",
+]
+
+
+def _get_engine():
     url = "postgresql://{user}:{password}@{host}:{port}/{dbname}".format(
         user=os.environ["POSTGRES_USER"],
         password=os.environ["POSTGRES_PASSWORD"],
@@ -18,12 +28,16 @@ def _elementary_schema_exists() -> bool:
         port=os.environ.get("POSTGRES_PORT", "5432"),
         dbname=os.environ["POSTGRES_DB"],
     )
-    engine = create_engine(
+    return create_engine(
         url,
         pool_pre_ping=True,
         connect_args={"connect_timeout": 10},
     )
 
+
+def _elementary_schema_exists() -> bool:
+    engine = _get_engine()
+
     from data_platform.resources import _retry_on_operational_error
 
     def _query():
@@ -69,9 +83,34 @@ def elementary_run_models(context: OpExecutionContext) -> None:
         raise Exception(f"dbt run elementary failed with exit code {returncode}")
 
 
+def _cleanup_old_elementary_data(context: OpExecutionContext) -> None:
+    """Delete elementary rows older than _DAYS_BACK to prevent OOM during report generation."""
+    engine = _get_engine()
+    total = 0
+    with engine.begin() as conn:
+        for table in _CLEANUP_TABLES:
+            result = conn.execute(
+                text(
+                    f"DELETE FROM elementary.{table} "  # noqa: S608
+                    f"WHERE created_at < now() - interval '{_DAYS_BACK} days'"
+                )
+            )
+            if result.rowcount:
+                context.log.info(
+                    f"Cleaned up {result.rowcount} old rows from elementary.{table}"
+                )
+                total += result.rowcount
+    if total:
+        context.log.info(f"Total rows cleaned: {total}")
+    else:
+        context.log.info("No old elementary data to clean up.")
+
+
 @op(ins={"after": In(Nothing)})
 def elementary_generate_report(context: OpExecutionContext) -> None:
     """Run edr report to regenerate the Elementary HTML report."""
+    _cleanup_old_elementary_data(context)
+
     report_path = (
         Path(__file__).parents[2] / "dbt" / "edr_target" / "elementary_report.html"
     )
diff --git a/tests/test_ops.py b/tests/test_ops.py
index dbb23f2..f67f918 100644
--- a/tests/test_ops.py
+++ b/tests/test_ops.py
@@ -9,6 +9,7 @@ from data_platform.ops.check_source_freshness import (
     SourceFreshnessConfig,
 )
 from data_platform.ops.elementary import (
+    _cleanup_old_elementary_data,
     _elementary_schema_exists,
     elementary_generate_report,
     elementary_run_models,
@@ -108,21 +109,62 @@ class TestElementaryRunModels:
 # elementary_generate_report
 
 
+class TestCleanupOldElementaryData:
+    @patch("data_platform.ops.elementary._get_engine")
+    def test_deletes_old_rows(self, mock_get_engine):
+        from unittest.mock import MagicMock
+
+        mock_conn = MagicMock()
+        mock_result = MagicMock()
+        mock_result.rowcount = 5
+        mock_conn.execute.return_value = mock_result
+        mock_engine = MagicMock()
+        mock_engine.begin.return_value.__enter__ = lambda _: mock_conn
+        mock_engine.begin.return_value.__exit__ = MagicMock(return_value=False)
+        mock_get_engine.return_value = mock_engine
+
+        context = build_op_context()
+        _cleanup_old_elementary_data(context)
+        assert mock_conn.execute.call_count == 4
+
+    @patch("data_platform.ops.elementary._get_engine")
+    def test_logs_when_no_rows_deleted(self, mock_get_engine):
+        from unittest.mock import MagicMock
+
+        mock_conn = MagicMock()
+        mock_result = MagicMock()
+        mock_result.rowcount = 0
+        mock_conn.execute.return_value = mock_result
+        mock_engine = MagicMock()
+        mock_engine.begin.return_value.__enter__ = lambda _: mock_conn
+        mock_engine.begin.return_value.__exit__ = MagicMock(return_value=False)
+        mock_get_engine.return_value = mock_engine
+
+        context = build_op_context()
+        _cleanup_old_elementary_data(context)
+        assert mock_conn.execute.call_count == 4
+
+
+# elementary_generate_report
+
+
+@patch("data_platform.ops.elementary._cleanup_old_elementary_data")
 class TestElementaryGenerateReport:
     @patch("data_platform.ops.elementary.subprocess.Popen")
-    def test_calls_edr_report(self, mock_popen):
+    def test_calls_edr_report(self, mock_popen, mock_cleanup):
         mock_popen.return_value = _mock_popen(
             returncode=0, stdout_lines=["report generated\n"]
         )
         context = build_op_context()
         elementary_generate_report(context)
+        mock_cleanup.assert_called_once()
         mock_popen.assert_called_once()
         args = mock_popen.call_args[0][0]
         assert "edr" in args
         assert "report" in args
 
     @patch("data_platform.ops.elementary.subprocess.Popen")
-    def test_raises_on_failure(self, mock_popen):
+    def test_raises_on_failure(self, mock_popen, mock_cleanup):
         mock_popen.return_value = _mock_popen(
             returncode=1, stdout_lines=["fatal error\n"]
         )
@@ -131,7 +173,7 @@ class TestElementaryGenerateReport:
             elementary_generate_report(context)
 
     @patch("data_platform.ops.elementary.subprocess.Popen")
-    def test_success_returns_none(self, mock_popen):
+    def test_success_returns_none(self, mock_popen, mock_cleanup):
         mock_popen.return_value = _mock_popen(returncode=0, stdout_lines=["done\n"])
         context = build_op_context()
         result = elementary_generate_report(context)