All shots must hit this wall before hitting the ground to keep the ball in play.
During the serve, the ball must hit the front wall first. Failure to do so results in a side out.
A shot hitting the crotch (area were the front wall meets the floor) results in side out or a point.
The service boxes, used in doubles play, are located at each end of the service zone and are designated by lines parallel with the side walls and 18 inches from the nearest side wall.
On each serve, the server's partner shall stand erect with back to the side wall and with both feet on the floor within the service box from the moment the server begins the service motion until the served ball passes the short line.
If the server's partner enters the safety zone before the ball passes the short line, the server loses service.
Any violations are called foot faults.
Drive Serve Lines
The drive serve lines, which form the drive serve zone, are parallel with the side wall and are within the service zone.
The drive serve lines are generally red or blue in color and unbroken.
The drive serve lines are 3 feet from each side wall in the service zone.
Viewed one at a time, the drive serve line divides the service area into a 3-foot and a 17-foot section that apply only to drive serves. The player may drive serve between the body and the side wall nearest to where the service motion began only if the player starts and remains outside of the 3-foot drive service zone.
In the event that the service motion begins in one 3-foot drive service zone and continues into the other 3-foot drive serve zone, the player may not hit a drive serve at all.
However, the drive serve zones are not observed for cross-court drive serves, the hard-Z, soft-Z, lob or half-lob serves.
The racquet may not break the plane of the 17-foot zone while making contact with the ball.
The drive serve line is not part of the 17-foot zone. Dropping the ball on the line or standing on the line while serving to the same side is an infraction.
Left Wall and Right Wall
If the ball hits a side wall before it hits the front wall on a serve only, then it is a sideout.
In all other cases, the side wall is considered in play as long as the ball hits the front wall before it touches the ground.
During a serve, the ball must hit the floor before it touches the back wall.
If the ball touches the back wall first, then the serve is considered a fault.
The ball can be hit after having hit the back wall, either towards the front or back at the back wall having the intention to eventually hit the front wall.
A shot hitting the crotch (area were the back wall meets the floor) is legal for both serves and regular play.