diff --git a/grapher.sh b/grapher.sh
index 52b30f0..750b975 100755
--- a/grapher.sh
+++ b/grapher.sh
@@ -23,7 +23,7 @@ for index in ${!period_filenames[*]}; do
         --step 60 \
         --title "Mail logfile statistics on `hostname -f` - $text" \
         --vertical-label "lines/minute" \
-        -h 200 -w 800 --slope-mode \
+        -h 200 -w 800 --slope-mode --watermark "`date`" \
         DEF:log_lines_total=$RRDFILE:log_lines_total:AVERAGE \
         DEF:log_lines_smtp=$RRDFILE:log_lines_smtp:AVERAGE \
         DEF:log_lines_smtpd=$RRDFILE:log_lines_smtpd:AVERAGE \
@@ -40,7 +40,7 @@ for index in ${!period_filenames[*]}; do
         --step 60 \
         --title "Inbound mail connections on `hostname -f` - $text" \
         --vertical-label "connections/minute" \
-        -h 200 -w 800 --slope-mode \
+        -h 200 -w 800 --slope-mode --watermark "`date`" \
         DEF:mi_connects=$RRDFILE:mi_connects:AVERAGE \
         DEF:mi_connects_tls=$RRDFILE:mi_connects_tls:AVERAGE \
         AREA:mi_connects#CC000033 \
@@ -54,7 +54,7 @@ for index in ${!period_filenames[*]}; do
         --step 60 \
         --title "Outbound mail on `hostname -f` - $text" \
         --vertical-label "mails/minute" \
-        -h 200 -w 800 --slope-mode \
+        -h 200 -w 800 --slope-mode --watermark "`date`" \
         DEF:mo_sent=$RRDFILE:mo_sent:AVERAGE \
         DEF:mo_deferred=$RRDFILE:mo_deferred:AVERAGE \
         DEF:mo_bncd_total=$RRDFILE:mo_bncd_total:AVERAGE \
@@ -83,7 +83,7 @@ for index in ${!period_filenames[*]}; do
         --step 60 \
         --title "Inbound mail on `hostname -f` - $text" \
         --vertical-label "mails/minute" \
-        -h 200 -w 800 --slope-mode \
+        -h 200 -w 800 --slope-mode --watermark "`date`" \
         DEF:mi_accept=$RRDFILE:mi_accept:AVERAGE \
         DEF:mi_reject=$RRDFILE:mi_reject:AVERAGE \
         DEF:mi_proxy_accept=$RRDFILE:mi_proxy_accept:AVERAGE \