A pressure indexing valve having an inlet assembly, a timer disk, a plunger assembly, a main body assembly, and an outlet assembly. The inlet assembly has an inlet endcap, a base, and a bypass housing which houses a ball, a ball return spring, and a set screw. The timer disk has flow thru-holes, an upper cam profile, and a lower cam profile. The plunger assembly has a piston, a plunger shaft, holes, and grommets. The main body assembly has a recess inset to receive the timer disk. The inlet assembly is secured onto the main body assembly to house the timer disk, and the plunger assembly. The outlet assembly has outlet passages, and outlet markers. The main body assembly is secured onto the outlet assembly.
