diff --git a/systemd/CMakeLists.txt b/systemd/CMakeLists.txt
index 16cbe86b5..659378d16 100644
--- a/systemd/CMakeLists.txt
+++ b/systemd/CMakeLists.txt
@@ -18,10 +18,14 @@ if(WITH_SYSTEMD)
     set(SYSTEMD_CONFIGURATIONS_FILES_DIR ${SYSTEMD_UNITDIR} )
 
     if(WITH_SYSTEMD_WATCHDOG)
-        set( DLT_WatchdogSec 2 )
+        if(NOT DEFINED DLT_WatchdogSec)
+            set(DLT_WatchdogSec 2 CACHE STRING "Watchdog timeout in seconds")
+        endif()
         message( STATUS "The systemd watchdog is enabled - timeout is set to ${DLT_WatchdogSec} seconds")
     else(WITH_SYSTEMD_WATCHDOG)
-        set( DLT_WatchdogSec 0 )
+        if(NOT DEFINED DLT_WatchdogSec)
+             set(DLT_WatchdogSec 0 CACHE STRING "Watchdog timeout in seconds")
+        endif()
         message( STATUS "The systemd watchdog is disabled")
     endif(WITH_SYSTEMD_WATCHDOG)