diff --git a/common/variables.common.subnets.tf b/common/variables.common.subnets.tf
index a4c5cfe..1e7f772 100644
--- a/common/variables.common.subnets.tf
+++ b/common/variables.common.subnets.tf
@@ -8,7 +8,8 @@ variable "public_subnets" {
     #      subnets     = list(string)
     #      labels      = list(string)
     #      availability_zones = list(string)
-    tags = map(string)
+    # optional
+    # tags = map(string)
   }))
   default = []
 }
@@ -23,7 +24,8 @@ variable "private_subnets" {
     #      subnets     = list(string)
     #      labels      = list(string)
     #      availability_zones = list(string)
-    tags = map(string)
+    # optional
+    # tags = map(string)
   }))
   default = []
 }