The ground staff have been very busy today, assumedly checking for any damage after the recent work.
I passed the racecourse at approximately one o’clock and they were out then; they took a bit of a break but are back now.
Edit: the sprinklers have now been turned on for about 100 yards after Tattenham Corner and into the straight.
Second edit: they are also watering the 5f chute, although nothing up the hill from Tattenham Corner.