Pressure testing lines

I'm building a new house on a slab. I laid all the drain pipes and called the inspector. He said they had to be pressure tested. He said to stick a 10 ft piece of pipe verticle to pressure test it. He didn't elaborate on it and left before I got a chance to talk to him myself. I was going to use an aircompressor to pressure test it but the 10ft pipe thing has me confused. And of course he hasn't returned my call. The only thing I can think of is to add the piece of pipe and fill it all with water. Would the extra 10ft of pipe add enough pressure to find any leaks?? Thanks

The inspector is telling you he wants to see a water test on the system. If you have a leak, the 10 ft of head pressure will be enough to find it as your water level in the 10ft of vertical piping will go down. In my neck of the woods we can either do a water test or we can put 5psi of air pressure on the system for test.