I am in the process of planning an outdoor bar/island under my deck and am trying to figure out where/how to drain the sink. My back yard sits below the first level of the house, but I have a bathroom in the basement with a ejector pump to pump up to main sewage drain. Has anyone cut out a section of basment floor and ran that way or what are other options?

How does storm drainage get out of the area? I assume that you have some sort of positive drainage away. I have my sink just draining into a gravel area under my deck, as a temporary measure of course. I just don't use it for much except the occassional washing of hands and getting a glass of water. This is surely not up to code in your area, but I plan to plumb it into my sanitary some day. I have also heard of others that have created some sort of underground gravel leaching pit of sorts, but I am not familiar with the details. Digging up the floor to get into your basement plumbing sounds pretty extreme, but I'm sure it could be done.

Riles

I think I'd dig a hole and bury a plastic barrel with a sump pump on a float switch to pump the water up to a drain line.

why not a french drain

I did what JohnT indicated for an outdoor shower/sink. I took a 55 gallon plastic trash can and buried underground completely and filled it up with drain stone. I drain the shower in the drum. To-date after a year, I have not seen any ground water. I did put a bunch of holes in the trashcan throughout the sides and bottom for drainage. It works great.