diff --git a/Makefile b/Makefile
index cbaa7938a..4df6c8ef1 100644
--- a/Makefile
+++ b/Makefile
@@ -66,7 +66,12 @@ smoketest:
 
 .PHONY: code-checks
 #code-checks: build version-and-path check-interfaces check-miscaptures -find-trailing-spaces -check-umids pyflakes
-code-checks: check-miscaptures -find-trailing-spaces -check-umids pyflakes
+code-checks: check-debugging check-miscaptures -find-trailing-spaces -check-umids pyflakes
+
+.PHONY: check-debugging
+check-debugging:
+	misc/coding_tools/check-debugging.sh
+	@echo
 
 .PHONY: check-miscaptures
 check-miscaptures:
diff --git a/misc/coding_tools/check-debugging.sh b/misc/coding_tools/check-debugging.sh
new file mode 100755
index 000000000..bfc0ca930
--- /dev/null
+++ b/misc/coding_tools/check-debugging.sh
@@ -0,0 +1,9 @@
+#!/bin/bash
+
+OUTPUT=$(grep -R '\.setDebugging(True)' src/allmydata)
+
+if [[ -n $OUTPUT ]] ; then
+    echo "Do not use defer.setDebugging(True) in production:"
+    echo $OUTPUT
+    exit 1
+fi