A balk or illegal pitch results in an immediate dead ball in high school baseball. If there is a balk but the pitcher delivers the ball and the batter hits or runners advance, the resulting action is meaningless because the ball is dead. If there is a balk or illegal pitch with runners on base, they each get one base. If there is an illegal pitch with no runners on base, a ball is added to the ball-strike count.
Note that a balk is also considered an illegal pitch under NFHS rules. If there are no runners and a pitcher does something that would be a balk with runners on base, it is considered an illegal pitch and a ball should be added to the count. However, sometimes it is practical for an umpire to give the pitcher a warning first and use it as a teachable moment.
If you umpire multiple levels, chances are you work a level where a balk is not always an immediate dead ball. Thus it becomes important not to signal a balk with the same signal as “time.” To avoid this, get in the habit of pointing at the pitcher when he balks, and voicing, “That’s a balk!” Then determine if time is to be called for that level of play. If it is not an immediate dead ball, you’ll want to get back into position for the pitch. Say the batter hits a home run after a balk/pitch on a level where the ball is not immediately dead for a balk. In that case the home run would stand.
[OBR: balk is not necessarily an immediate dead ball; a pitch or throw occurring right after the balk is allowed. If the batter and/or all runners advance at least one base as a result of the pitch or throw, the balk is nullified.]