diff --git a/README.md b/README.md
index 0ca38a1..04fab38 100644
--- a/README.md
+++ b/README.md
@@ -82,6 +82,8 @@ Examples:
 | `on 3/25`            | Once a year on March 25                       |
 | `on */7`             | Each month on the 7th                         |
 
+The timeout for a source's fetches and other actions can be set on the source via the environment variable `INTAKE_TIMEOUT`.
+
 ### Action API
 
 The Intake action API defines how programs should behave to be used with Intake sources.