The only opportunity you need to use a drill when installing a drip irrigation system is when you are installing the drip emitters. They’ve barbed connectors made to fit into 1/4-inch polybutylene tubing, and should you install them directly to the 1/2- or 5/8-inch main PB waterlines, then you need to make holes for them. You can purchase a punch to produce these holes, but the punch can be difficult to use, particularly in sunny weather once the tubing is hot and pliable. A drill makes the job of punching the holes simpler.
Fit a variable-speed drill with a 3-16-inch drill bit. It will make a hole slightly smaller in diameter than the barbs of the emitters, ensuring a tight fit.
Mark the place on a span of 1/2- or 5/8-inch tubing on that you would like to set up an emitter, using a nail to make an indentation. Hold the tube securely with one hand so that the mark is between the fingers and squeeze it gently to keep the tube.
Place the drill on a low rate and drill during the mark. Stop drilling after you penetrate the plastic, and take away the little bit to prevent drilling through the opposing side of this tubing.