diff --git a/plugins/systemd/systemd_units b/plugins/systemd/systemd_units
index 33e59115..dc12d463 100755
--- a/plugins/systemd/systemd_units
+++ b/plugins/systemd/systemd_units
@@ -13,7 +13,17 @@ Linux systems with systemd installed.
 
 =head1 CONFIGURATION
 
-None needed.
+None needed. You may optionally pass warning and critical values for any of the possible states (active,
+reloading, inactive, failed, activating, deactivating) like so:
+
+ [systemd_units]
+     env.failed_warning 0
+     env.failed_critical 5
+     env.inactive_warning 10
+     env.inactive_critical 20
+     
+Note that for failed units, default warning and critical values are set to 0 and 10, respectively. No other
+states have default levels set.
 
 =head1 AUTHOR
 
@@ -30,6 +40,11 @@ GPLv2
 
 =cut
 
+. "$MUNIN_LIBDIR/plugins/plugin.sh"
+
+failed_warning="${failed_warning:-0}"
+failed_critical="${failed_critical:-10}"
+
 states="active \
 	reloading \
 	inactive \
@@ -52,10 +67,8 @@ EOF
 	for state in $states; do
 		echo "$state.label $state"
 		echo "$state.draw AREASTACK"
-		if [ "$state" = "failed" ]; then
-			echo "$state.warning 0"
-			echo "$state.critical 10"
-		fi
+		print_warning $state
+		print_critical $state
 	done
 }