diff --git a/doc/api/stream.md b/doc/api/stream.md
index 6f5fdd05a15d82..8af87cce29ac80 100644
--- a/doc/api/stream.md
+++ b/doc/api/stream.md
@@ -964,6 +964,7 @@ added:
 * {boolean}
 
 Is `true` if the stream's buffer has been full and stream will emit `'drain'`.
+This flag does not update immediately after each write and remains `true` until the writable stream drains and the `drain` event is emitted.
 
 ##### `writable.writableObjectMode`