diff --git a/README.md b/README.md
index a1efe31a..03ccb69a 100644
--- a/README.md
+++ b/README.md
@@ -272,7 +272,7 @@ Available targets:
 | <a name="input_allow_ssl_requests_only"></a> [allow\_ssl\_requests\_only](#input\_allow\_ssl\_requests\_only) | Set to `true` to require requests to use Secure Socket Layer (HTTPS/SSL). This will explicitly deny access to HTTP requests | `bool` | `false` | no |
 | <a name="input_allowed_bucket_actions"></a> [allowed\_bucket\_actions](#input\_allowed\_bucket\_actions) | List of actions the user is permitted to perform on the S3 bucket | `list(string)` | <pre>[<br>  "s3:PutObject",<br>  "s3:PutObjectAcl",<br>  "s3:GetObject",<br>  "s3:DeleteObject",<br>  "s3:ListBucket",<br>  "s3:ListBucketMultipartUploads",<br>  "s3:GetBucketLocation",<br>  "s3:AbortMultipartUpload"<br>]</pre> | no |
 | <a name="input_attributes"></a> [attributes](#input\_attributes) | ID element. Additional attributes (e.g. `workers` or `cluster`) to add to `id`,<br>in the order they appear in the list. New attributes are appended to the<br>end of the list. The elements of the list are joined by the `delimiter`<br>and treated as a single ID element. | `list(string)` | `[]` | no |
-| <a name="input_availability_zone_id"></a> [availability\_zone\_id](#input\_availability\_zone\_id) | The ID of the availability zone. | `string` | `null` | no |
+| <a name="input_availability_zone_id"></a> [availability\_zone\_id](#input\_availability\_zone\_id) | The ID of the availability zone. | `string` | `""` | no |
 | <a name="input_block_public_acls"></a> [block\_public\_acls](#input\_block\_public\_acls) | Set to `false` to disable the blocking of new public access lists on the bucket | `bool` | `true` | no |
 | <a name="input_block_public_policy"></a> [block\_public\_policy](#input\_block\_public\_policy) | Set to `false` to disable the blocking of new public policies on the bucket | `bool` | `true` | no |
 | <a name="input_bucket_key_enabled"></a> [bucket\_key\_enabled](#input\_bucket\_key\_enabled) | Set this to true to use Amazon S3 Bucket Keys for SSE-KMS, which may or may not reduce the number of AWS KMS requests.<br>For more information, see: https://docs.aws.amazon.com/AmazonS3/latest/userguide/bucket-key.html | `bool` | `false` | no |