grade
There are many ways. Some levels have a line on the bubble for 1/4" grade. Ridgid, and other companies, made a level with a stud on one end which you could adjust for any pitch you wanted. The surveyor's level is another way, but it takes two people, and unless it is self leveling, like mine is, it takes time to set it up. You could also use a laser leveling device which "tweedles" when the target is at the proper point.