diff --git a/src/taskgraph/util/verify.py b/src/taskgraph/util/verify.py
index 90402763..30da0c55 100644
--- a/src/taskgraph/util/verify.py
+++ b/src/taskgraph/util/verify.py
@@ -235,10 +235,14 @@ def verify_routes_notification_filters(
                 )
 
 
+# https://docs.taskcluster.net/docs/reference/core/index#valid-characters
+INDEX_NAMESPACE_RE = re.compile(r"^([a-zA-Z0-9_!~*'()%-]+\.)*[a-zA-Z0-9_!~*'()%-]+$")
+
+
 @verifications.add("full_task_graph")
 def verify_index_route(task, taskgraph, scratch_pad, graph_config, parameters):
     """
-    This function ensures that routes do not contain forward slashes.
+    This function ensures that index routes would create valid taskcluster index paths
     """
     if task is None:
         return
@@ -247,11 +251,13 @@ def verify_index_route(task, taskgraph, scratch_pad, graph_config, parameters):
     route_prefix = "index."
 
     for route in routes:
-        # Check for invalid / in the index route
-        if route.startswith(route_prefix) and "/" in route:
-            raise Exception(
-                f"{task.label} has invalid route with forward slash: {route}"
-            )
+        if route.startswith(route_prefix):
+            namespace = route[len(route_prefix) :]
+            if not INDEX_NAMESPACE_RE.match(namespace):
+                raise Exception(
+                    f"{task.label} has invalid index route namespace: {route}. "
+                    f"Namespace must match {INDEX_NAMESPACE_RE.pattern}"
+                )
 
 
 @verifications.add("full_task_graph")
diff --git a/test/test_util_verify.py b/test/test_util_verify.py
index 542ba09b..91eccf23 100644
--- a/test/test_util_verify.py
+++ b/test/test_util_verify.py
@@ -211,6 +211,17 @@ def make_task_treeherder(label, symbol, platform="linux/opt"):
             pytest.raises(DeprecationWarning),
             id="routes_notfication_filter: deprecated",
         ),
+        pytest.param(
+            "verify_index_route",
+            make_graph(
+                make_task(
+                    "valid_route",
+                    task_def={"routes": ["index.example.v2.latest.taskgraph.decision"]},
+                ),
+            ),
+            does_not_raise(),
+            id="verify_index_route: valid route",
+        ),
         pytest.param(
             "verify_index_route",
             make_graph(
@@ -226,6 +237,28 @@ def make_task_treeherder(label, symbol, platform="linux/opt"):
             pytest.raises(Exception),
             id="verify_index_route: invalid slash in route",
         ),
+        pytest.param(
+            "verify_index_route",
+            make_graph(
+                make_task(
+                    "invalid_plus",
+                    task_def={"routes": ["index.example.1.0+hotfix1.latest"]},
+                ),
+            ),
+            pytest.raises(Exception),
+            id="verify_index_route: invalid plus in route",
+        ),
+        pytest.param(
+            "verify_index_route",
+            make_graph(
+                make_task(
+                    "invalid_space",
+                    task_def={"routes": ["index.example.some namespace.latest"]},
+                ),
+            ),
+            pytest.raises(Exception),
+            id="verify_index_route: invalid space in route",
+        ),
         pytest.param(
             "verify_task_dependencies",
             make_graph(