Is there a tool to measure the slope of plumbing piping to see if it meets a code or specification?

I am overseeing the construction of a building and am being told that some of the new plumbing piping does not meet the 1/4" to 10' or 1/8" to 10' slope that the Engineer specified based on the local City Plumbing Code. A plumber I talked to had mentioned that he thought there was a tool available that was a level that you could set the 1/4" or 1/8" to 10' slope and verify that the piping slope meets the code. Does anyone know of this tool and where to get it? I'd rather not do the measuring (with a tape measure and calulator) to verify the slope if there is an easier way. Thanks. Something like this: http://www.mytoolstore.com/starrett/level01.html but hopefully less expensive (thanks jaszzman for the search words) Yes, 1/4" and 1/8" in 1', not 10' (typo.)

Public Comments

yeah its called a string and a string level and a framing square you run the sting level along the pipe and measure the pipe at the start and the pipe and the end and do the math o and a tape measure or who ever put the pipe in make sure you tell them to make it to code like they are supost to do
Go to a plumbing supply house (not home depot or such) and ask for a level that has an adjustable foot on one end. A four foot level should do the job. You need a sixteenth in four feet for drain lines..
take an old 4 ft level and put a screw in the very end and leave it out just under an 1/8 in. ...when laid on the pipe and the level reads level it should have the right amount of fall for 1/4 in. in 10 ft...an 1/8 in. in 10 ft. does not even compute for a dumbricklayer...
It's called a graduated level Ive seen them in 9" and 24" lengths I'm sure you can get them in 4' and you are looking for a 1/4" per foot on 4" and under and 1/8" per foot on 4" and over of course these are minimums