diff --git a/conftest.py b/conftest.py
index 6f644831..191d886e 100644
--- a/conftest.py
+++ b/conftest.py
@@ -28,6 +28,12 @@ def pytest_addoption(parser):
         default=False,
         help="run expensive tests",
     )
+    parser.addoption(
+        "--sanitycheck",
+        action="store_true",
+        default=False,
+        help="run sanity checks",
+    )
 
 
 def pytest_configure(config):
@@ -39,6 +45,10 @@ def pytest_configure(config):
     config.addinivalue_line(
         "markers", "runexpensive: mark test to run expensive tests"
     )
+    config.addinivalue_line(
+        "markers",
+        "sanitycheck: mark test to run checks in dependencies' code.",
+    )
 
 
 def pytest_collection_modifyitems(config, items):  # noqa:C901
@@ -47,6 +57,7 @@ def pytest_collection_modifyitems(config, items):  # noqa:C901
         config.getoption("--runsetup")
         & config.getoption("--runinteg")
         & config.getoption("--runexpensive")
+        & config.getoption("--sanitycheck")
     ):
         # do full test suite when all flags are given
         return
@@ -75,3 +86,12 @@ def pytest_collection_modifyitems(config, items):  # noqa:C901
         for item in items:
             if "runexpensive" in item.keywords:
                 item.add_marker(skip_runexpensive)
+
+    # do not add sanitycheck marks when the sanitycheck flag is given
+    if not config.getoption("--sanitycheck"):
+        skip_sanitycheck = pytest.mark.skip(
+            reason="need --sanitycheck option to run"
+        )
+        for item in items:
+            if "sanitycheck" in item.keywords:
+                item.add_marker(skip_sanitycheck)
diff --git a/tests/gtfs/test_validation.py b/tests/gtfs/test_validation.py
index 038d988f..54dff447 100644
--- a/tests/gtfs/test_validation.py
+++ b/tests/gtfs/test_validation.py
@@ -117,7 +117,7 @@ def test_is_valid(self, gtfs_fixture):
             found_cols == exp_cols
         ).all(), f"Expected columns {exp_cols}. Found: {found_cols}"
 
-    @pytest.mark.runinteg
+    @pytest.mark.sanitycheck
     def test_trips_unmatched_ids(self, gtfs_fixture):
         """Tests to evaluate gtfs-klt's reaction to invalid IDs in trips.
 
@@ -167,7 +167,7 @@ def test_trips_unmatched_ids(self, gtfs_fixture):
         ), "gtfs-kit failed to recognise invalid service_id"
         assert len(new_valid) == 10, "Validation table not expected size"
 
-    @pytest.mark.runinteg
+    @pytest.mark.sanitycheck
     def test_routes_unmatched_ids(self, gtfs_fixture):
         """Tests to evaluate gtfs-klt's reaction to invalid IDs in routes.
 
@@ -206,7 +206,7 @@ def test_routes_unmatched_ids(self, gtfs_fixture):
         ), "gtfs-kit failed to recognise that there are routes with no trips"
         assert len(new_valid) == 9, "Validation table not expected size"
 
-    @pytest.mark.runinteg
+    @pytest.mark.sanitycheck
     def test_unmatched_service_id_behaviour(self, gtfs_fixture):
         """Tests to evaluate gtfs-klt's reaction to invalid IDs in calendar.