Decks, Patios, Porches and Docks - Footing trouble

I was digging the footings for a deck stair landing, when I hit gravel. The footing that I was digging was only about 2" away from the poured concrete foundation of my split foyer house, and 30" deep (code requirement). I am assuming that this gravel is a few inches deep, and that it is covering the corrugated drain pipe that leads to the sump pit inside the house. The landing that I am building is 36" x 36" and will be supported 70" above the ground by 4"x4" corner posts. My question is will pouring the footing and the wieght of the structure collapse the pipe and block the flow of ground water to the sump? Can you suggest any other support methods? Attaching a ledger to the house is not an option at this point. Please tell me it won't crush the pipe. Thanks for your help.

Perhaps I'm misunderstanding you, but I thought that the french drain pipe was inside the foundation, not outside. The purpose is to channel water that gets inside the foundation to the sump pit. As far as I can tell, you are putting the deck stairs outside, so I don't think you would have a chance of hitting any inside drain pipe. Outside drain pipe maybe, if there is a drain system installed around the outside of the foundation, but no chance are you hitting a pipe that channels water into your sump pump.

Disclaimer: I'm by no means an expert on drainage.

Thanks for the help, I was worried for nothing. For some reason I thought that the drain tile ran on the outside of the foundation, near the footing to collect water that runs down the wall. Thanks for the quick reply! I'll pour the footers tomorrow.

French drains are typically installed on the outside of the foundation on any conventional and late model home. ("late model" meaning from about the late 50s or early 60s up until today)

This means if you are digging into your soil around the foundation and encounter crushed stone, you almost assuredly have a conventional french drain system around the outside of the foundation and you can compromise it by bearing the posts for a deck or stair above it in this location.

Proceed no further until you have the site examined by your code enforcement office and/or a structural engineer or architect.