diff --git a/doc/ubuntu-dev-tools.5 b/doc/ubuntu-dev-tools.5
index be239e3..7325f86 100644
--- a/doc/ubuntu-dev-tools.5
+++ b/doc/ubuntu-dev-tools.5
@@ -57,6 +57,11 @@ The currently recognised package\-wide variables are:
 This specifies the preferred test\-builder, one of
 .BR pbuilder " (default), " sbuild ", " pbuilder\-dist .
 
+.TP
+.B UBUNTUTOOLS_UPDATE_BUILDER
+Boolean. Whether or not to update the test\-builder before each test
+build.
+
 .TP
 .B UBUNTUTOOLS_LPINSTANCE
 The launchpad instance to communicate with. e.g. \fBproduction\fR