Time allowed between pitches

Can the pitcher stand on the pitcher’s plate longer than 10 seconds with her hands apart?  Yes, and maybe up to 20 seconds!  How, you ask, with the 10-10-5 rule (10.18)?  The first 10 seconds of what we affectionately call the 10-10-5 rule applies to both the pitcher and batter.
Once the PU determines this first 10-second count should start, the pitcher must be on the pitcher’s plate and the batter in the batter’s box within this10 seconds.  After they are both in position the pitcher has 10 seconds to bring her hands together.
Example: the pitcher gets on the pitcher’s plate almost immediately after she receives the ball from the catcher.  The batter takes exactly 10 seconds to get into the box, during which the pitcher is still standing on the plate with her hands apart (10 seconds have elapsed so far).
NOW AND ONLY NOW the second 10-second count begins.  If the pitcher now takes 10 seconds to bring her hands together, a total of 20 seconds has elapsed.  This is perfectly legal, but let’s hope this does not happen too often in  your game!!
Mechanic if both pitcher and batter are taking too long
The plate umpire should step out from behind the plate remove mask and call dead ball.
Point emphatically to the pitcher and say – “You must step on the pitcher’s plate in 10 seconds.”
Point emphatically to the batter and say – “you must be in the batter’s box within 10 seconds.”
Put the mask on, step back behind the catcher and say “Play ball.”
The next time either a pitcher or batter violates the rule, call the violation.