diff --git a/webapp/build.xml b/webapp/build.xml
index c253da84a..d7e0e94dc 100644
--- a/webapp/build.xml
+++ b/webapp/build.xml
@@ -203,9 +203,16 @@ deploy   - Deploy the application directly into the Tomcat webapps directory.
 			<fileset dir="${webapp.dir}" includes="submodels/**/*" />
 		</copy>
 
-		<copy file="${webapp.dir}/config/default.log4j.properties"
-		      tofile="${build.dir}/war/WEB-INF/classes/log4j.properties"
-		      filtering="true">
+		<!-- use the production Log4J properties, unless a debug version exists. -->
+		<available file="${webapp.dir}/config/debug.log4j.properties"
+		           property="debug.log4j.exists" />
+		<copy tofile="${build.dir}/war/WEB-INF/classes/log4j.properties"
+		      filtering="true"
+		      overwrite="true">
+			<fileset dir="${webapp.dir}/config">
+				<include name="default.log4j.properties" unless="debug.log4j.exists" />
+				<include name="debug.log4j.properties" if="debug.log4j.exists" />
+			</fileset>
 			<filterchain>
 				<expandproperties />
 			</filterchain>
diff --git a/webapp/config/default.log4j.properties b/webapp/config/default.log4j.properties
index 802c5c656..e55941a39 100644
--- a/webapp/config/default.log4j.properties
+++ b/webapp/config/default.log4j.properties
@@ -19,6 +19,9 @@
 #
 # More information can be found here:
 # http://logging.apache.org/log4j/1.2/manual.html
+#
+# The "production" version of this file is default.log4j.properties.
+# debug.log4j.properties exists will be used instead, if it exists, but is not stored in Subversion.
  
 log4j.appender.AllAppender=org.apache.log4j.RollingFileAppender 
 log4j.appender.AllAppender.File= ${tomcat.home}/logs/${webapp.name}.all.log