diff --git a/meson_options.txt b/meson_options.txt
index d5237f02ae..814f340840 100644
--- a/meson_options.txt
+++ b/meson_options.txt
@@ -223,7 +223,7 @@ option('status-unit-format-default', type : 'combo',
 option('time-epoch', type : 'integer', value : 0,
        description : 'time epoch for time clients')
 option('clock-valid-range-usec-max', type : 'integer', value : 473364000000000, # 15 years
-       description : 'maximum value in microseconds for the difference between RTC and epoch, exceeding which is considered an RTC error')
+       description : 'maximum value in microseconds for the difference between RTC and epoch, exceeding which is considered an RTC error ["0" disables]')
 option('default-user-shell', type : 'string', value : '/bin/bash',
        description : 'default interactive shell')
 
diff --git a/src/shared/clock-util.c b/src/shared/clock-util.c
index eb6f12a255..a4c00d713e 100644
--- a/src/shared/clock-util.c
+++ b/src/shared/clock-util.c
@@ -153,7 +153,7 @@ int clock_apply_epoch(ClockChangeDirection *ret_attempted_change) {
         now_usec = now(CLOCK_REALTIME);
         if (now_usec < epoch_usec)
                 *ret_attempted_change = CLOCK_CHANGE_FORWARD;
-        else if (now_usec > usec_add(epoch_usec, CLOCK_VALID_RANGE_USEC_MAX))
+        else if (CLOCK_VALID_RANGE_USEC_MAX > 0 && now_usec > usec_add(epoch_usec, CLOCK_VALID_RANGE_USEC_MAX))
                 *ret_attempted_change = CLOCK_CHANGE_BACKWARD;
         else {
                 *ret_attempted_change = CLOCK_CHANGE_NOOP;