How do I find all of my lines?

I am considering building a deck next to a sun room. The deck would be over the area where the pool lines come in and out. I need to know where everything is so they dont hit anything building the deck.

For the main pool we have 3 jets, 2 skimmers and the drain line. It also has electricity for lights. We have a spa that is also part of the system. It has a drain and 3 jets.

Will all of these pipes be in one ditch until they get to the pool or will I have 7 or 8 different pipes coming into the pump system?

Without digging the entire area up, is there a way to trace the pipes? I called the company that built the pool but they don't have the schematics.

I am able to control the flow of water to and from the pool and spa so I know those have to be at least 4 separate pipes.

Any suggestions?