diff --git a/caddy/content.md b/caddy/content.md
index 95353a4b2..6c802113f 100644
--- a/caddy/content.md
+++ b/caddy/content.md
@@ -131,5 +131,8 @@ services:
 
 volumes:
   caddy_data:
+    external: true
   caddy_config:
 ```
+
+Defining the data volume as [`external`](https://docs.docker.com/compose/compose-file/compose-file-v3/#external) makes sure `docker-compose down` does not delete the volume. You may need to create it manually using `docker volume create [project-name]_caddy_data`.